RESUMO
Three experiments were conducted to evaluate the effects of long-acting injectable progesterone (iP4) in buffalo cows. In Experiment 1, ovariectomized buffaloes received 300 mg (iP300) or 600 mg (iP600) of iP4, and serum P4 concentrations were evaluated. In experiment 2, three groups were compared: control or administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after timed artificial insemination (TAI). On day 16, reproductive tract was recovered for conceptus, endometrium, and corpus luteum (CL) analysis. In experiment 3, pregnancy per AI (P/TAI) and proportion of pregnancy losses were evaluated after administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after TAI in lactating buffaloes. In experiment 1, serum P4 concentrations remained over 1 ng/mL for ~ 3 days in both groups. The 300 mg dose was used in subsequent experiments. In experiment 2, CL weight and endometrial glands density were decreased, and conceptus length was increased in iP4-D3 compared to control and to iP4-D6 (P < 0.05). Transcript abundance of Prostaglandin F Receptor (FP) and ISG15 in CL and of ISG15 and MX1 in endometrium was greater in iP4-D3 when compared to control and to iP4-D6 (P < 0.05). In experiment 3, there was no difference among experimental groups for P/TAI at D30 and pregnancy losses (P > 0.1); however, iP4-D3 presented a lower P/TAI at day 60 (41.7%) when compared to control (56.8%) and iP4-D6 (57.7%; P = 0.07). In conclusion, administration iP4 at 3 days after TAI affects CL development and consequently decreases final pregnancy outcome in buffaloes.
Assuntos
Bison , Búfalos , Animais , Feminino , Bovinos , Gravidez , Progesterona , Lactação , Inseminação Artificial/veterinária , Luteína , Suplementos NutricionaisRESUMO
Prior to implantation in cattle, the mucous medium contained in the uterine lumen serves as a working interface for molecular exchange and signaling between the lining endometrium and the embryo. The composition of this luminal fluid changes temporally according to the secretory and reabsorptive activities of the uterus and the embryo, which are under complex regulation. Via this interface, both the embryo and the endometrium reprogram each other's functions to support pregnancy continuation beyond the pre-implantation period. More specifically, the embryo receives elongation signals and the uterus receives anti-luteolytic stimuli. Here, characteristics of the luminal compartment as well as the regulation of its composition to determine the pregnancy outcome will be discussed.
RESUMO
The canine corpus luteum (CL) is able to synthetise, activate and deactivate 17b-estradiol (E2) and also expresses nuclear estrogen receptors in a time-dependent manner during diestrus. Nevertheless, we are still missing a better comprehension of E2 functions in the canine CL, especially regarding the specific roles of estrogen receptor alpha (ERa) and ERb, encoded by ESR1 and 2, respectively. For that purpose, we analyzed transcriptomic data of canine non-pregnant CL collected on days 10, 20, 30, 40, 50 and 60 of diestrus and searched for differentially expressed genes (DEG) containing predicted transcription factor binding sites (TFBS) for ESR1 or ESR2. Based on biological functions of DEG presenting TFBS, expression of select transcripts and corresponding proteins was assessed. Additionally, luteal cells were collected across specific time points during diestrus and specificity of E2 responses was tested using ERa and/or ERb inhibitors. Bioinformatic analyses revealed 517 DEGs containing TFBS, from which 67 for both receptors. In general, abundance of predicted ESR1 targets was greater in the beginning, while abundance of ESR2 targets was greater in the end of diestrus. ESR1/ESR2 ratio shifted from an increasing to a decreasing pattern from day 30 to 40 post ovulation. Specific receptor inhibition suggested an ERa-mediated positive regulation of CL function at the beginning of diestrus and an ERb-mediated effect contributing to luteal regression. In conclusion, our data points toward a broad spectrum of action of E2 and its nuclear receptors, which can also act as transcription factors for other genes regulating canine CL function.
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In brief: Elevated temperatures disturbed sperm physiology. Bovine sperm cells exposed to heat shock led to diminished mitochondrial activity, fertilizing ability, increased oxidative stress and caspase activity concomitant with a delay in embryonic developmental kinetics and modulation of sperm-borne microRNAsmiRNAs. Abstract: Sperm function is susceptible to adverse environmental conditions. It has been demonstrated that in vivo and in vitro exposure of bovine sperm to elevated temperature reduces sperm motility and fertilizing potential. However, the cascade of functional, cellular, and molecular events triggered by elevated temperature in the mature sperm cell remains not fully understood. Therefore, the aim of this study was to determine the effect of heat shock on mature sperm cells. Frozen-thawed Holstein sperm were evaluated immediately after Percoll purification (0 h non-incubation control) or after incubation at 35, 38.5, and 41°C for 4 h. Heat shock reduced sperm motility after 3-4 h at 41°C while mitochondrial activity was reduced by 38.5 and 41°C when compared to the control. Heat shock also increased sperm reactive oxygen species production and caspase activity. Heat-shocked sperm had lower fertilizing ability, which led to diminished cleavage and blastocyst rates. Preimplantation embryo developmental kinetics was also slowed and reduced by sperm heat shock. The microRNA (miR) profiling identified >300 miRs in bovine sperm. Among these, three and seven miRs were exclusively identified in sperm cells exposed to 35 and 41°C, respectively. Moreover, miR-181d was enriched in sperm cells exposed to higher temperatures. Hence, elevated temperature altered the physiology of mature sperm cells by perturbing cellular processes and the miR profile, which collectively led to lower fertilizing ability and preimplantation development.
Assuntos
MicroRNAs , Preservação do Sêmen , Animais , Caspases , Bovinos , Resposta ao Choque Térmico , Masculino , MicroRNAs/genética , Espécies Reativas de Oxigênio , Sêmen , Motilidade dos Espermatozoides , Espermatozoides/fisiologiaRESUMO
Prior to implantation in cattle, the mucous medium contained in the uterine lumen serves as a working interface for molecular exchange and signaling between the lining endometrium and the embryo. The composition of this luminal fluid changes temporally according to the secretory and reabsorptive activities of the uterus and the embryo, which are under complex regulation. Via this interface, both the embryo and the endometrium reprogram each other's functions to support pregnancy continuation beyond the pre-implantation period. More specifically, the embryo receives elongation signals and the uterus receives anti-luteolytic stimuli. Here, characteristics of the luminal compartment as well as the regulation of its composition to determine the pregnancy outcome will be discussed.(AU)
Assuntos
Animais , Feminino , Gravidez , Bovinos/fisiologia , Endométrio/embriologia , Reprogramação Celular/fisiologia , Hormônios Esteroides Gonadais , Luteolíticos/análiseRESUMO
Climate change is a reality and global surface temperature is projected to rise substantially in the next 80 years. Agriculture practices will have to adapt to climate change, and also help to mitigate this effect using, among other strategies, forest conservation and management. Silvopastoral systems have been adopted in tropical climate livestock areas but their benefits on thermal comfort and reproductive performance of beef cows are not completely known. Therefore, our aims were to compare the microclimate of silvopastoral and intensive rotational unshaded grazing systems in different months and to evaluate physiological variables (Exp. 1 and 2), metabolism, and in vitro embryo production (Exp. 2) in crossbred beef females. Our hypothesis is that the silvopastoral system can improve the thermal comfort of beef heifers and cows and, consequently, also improve dry matter intake, body weight gain, and in vitro embryo production when compared to the unshaded rotational grazing system. In Exp 1, the silvopastoral system decreased body temperature and increased welfare and performance of heifers. In Exp. 2, the silvopastoral system enhanced the body weight but did not affect metabolism and the general reproductive performance, but increased the recovery rate of oocytes in primiparous cows.
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This review focuses on the innate immune events modulated by conceptus signaling during early pregnancy in ruminants. Interferon-tau (IFN-τ) plays a role in the recognition of pregnancy in ruminants, which involves more than the inhibition of luteolytic pulses of PGF2α to maintain corpus luteum function. For successful pregnancy establishment, the allogenic conceptus needs to prevent rejection by the female. Therefore, IFN-τ exerts paracrine and endocrine actions to regulate the innate immune system and prevent conceptus rejection. Additionally, other immune regulators work in parallel with IFN-τ, such as the pattern recognition receptors (PRR). These receptors are activated during viral and bacterial infections and in early pregnancy, but it remains unknown whether PPR expression and function are controlled by IFN-τ. Therefore, this review focuses on the main components of the innate immune response that are involved with early pregnancy and their importance to avoid conceptus rejection.
RESUMO
This review focuses on the innate immune events modulated by conceptus signaling during early pregnancy in ruminants. Interferon-tau (IFN-) plays a role in the recognition of pregnancy in ruminants, which involves more than the inhibition of luteolytic pulses of PGF2 to maintain corpus luteum function. For successful pregnancy establishment, the allogenic conceptus needs to prevent rejection by the female. Therefore, IFN- exerts paracrine and endocrine actions to regulate the innate immune system and prevent conceptus rejection. Additionally, other immune regulators work in parallel with IFN-, such as the pattern recognition receptors (PRR). These receptors are activated during viral and bacterial infections and in early pregnancy, but it remains unknown whether PPR expression and function are controlled by IFN-. Therefore, this review focuses on the main components of the innate immune response that are involved with early pregnancy and their importance to avoid conceptus rejection.(AU)
Assuntos
Animais , Feminino , Gravidez , Ruminantes/embriologia , Ruminantes/imunologia , Prenhez , Luteólise , Sistema Imunitário , Interleucinas , DinoprostaRESUMO
The release of endometrial prostaglandin-F2α (PGF2α) in bovine females can be induced in vivo by estradiol (E2). However, its role in this mechanism has not been clarified. We hypothesized that E2 stimulates the activity and abundance of protein kinase C (PKC) and phospholipase A2 (PLA2). Our objective in this study was to analyze the effects of PKC and PLA2 inhibitors on PGF2α synthesis induced by E2 and calcium ionophore (CI) in bovine endometrial cells (BEND cells; Experiment 1). Additionally, we evaluated the abundance of PKC and PLA2 in endometrial explants of cows treated or not with E2 17 days after estrus (D17, D0 = estrus; Experiment 2). In Experiment 1, BEND cells were submitted to a PKC inhibitor (10 µM of C25H24N4O2; bisindolylmaleimide I, or BIS I), a PLA2 inhibitor (20 µM of arachydoniltrifluoromethane or AACOCF3), or none. The BEND cells were subsequently treated with E2 and CI, and PGF2α concentrations were measured in the culture medium through radioimmunoassay. For DIF-12 (PGF2α concentration 12 h after treatment subtracted from PGF2α concentration at hour 0), no PKC inhibitor effect was observed (P= 0.2709). However, DIF-12 was lower (P < 0.05) for groups treated with the PLA2 inhibitor and PLA2 inhibitor + CI + E2 groups than the control and CI + E2 groups. Thus, AACOCF3 was an efficient PLA2 inhibitor in the BEND cells culture system, and E2 did not stimulate the synthesis of PKC and PLA2. In Experiment 2, cyclic Nellore heifers received none (n = 5) or 3 mg (n = 6) of 17ß-E2 on D17 and were slaughtered 2 h after administration. The abundance of PKC and PLA2 in the endometrial tissue was evaluated using Western blotting analysis. No E2 effect was observed on PKC (P = 0.08) and PLA2 (P = 0.56). We concluded that E2 did not stimulate the activity and abundance of PKC and PLA2.(AU)
A liberação endometrial de prostaglandina-F2α (PGF2α) em fêmeas bovinas pode ser induzida in vivo pelo estradiol (E2). Entretanto o seu mecanismo de ação ainda não foi bem esclarecido. Nossa hipótese é que o E2 estimula a atividade e a abundância da proteína quinase C (PKC) e da fosfolipase A2 (PLA2). Nosso objetivo com este estudo foi analizar os efeitos de inibidores de PKC e PLA2 na síntese de PGF2α induzida por E2 e ionóforo de cálcio (CI) em células endometriais bovinas (células BEND; Experimento 1). Adicionalmente, nós avaliamos a abundância de PKC e PLA2 em explantes endometriais de vacas tratadas com ou sem E2 17 dias após o estro (D17, D0 = estro; Experimento 2). No Experimento 1, células BEND foram submetidas ao inibidor de PKC (10 µM de C25H24N4O2; bisindolylmaleimide I, ou BIS I), e ao inibidor de PLA2 (20 µM de arachydoniltrifluoromethane ou AACOCF3) ou a nenhum inibidor. As células BEND foram subsequentemente tratadas com E2 e CI e concentrações de PGF2α foram mensuradas no meio de cultura por radioimunoenssaio. Para DIF-12 (concentração de PGF2α 12 horas depois do tratamento, subtraída da concentração de PGF2α na hora 0), não foi observado efeito do inibidor de PKC (P = 0.2709). Entretanto DIF-12 foi menor (P < 0.05) nos grupos tratados com inibidor de PLA2 e inibidor de PLA2 + CI + E2 quando comparados com o grupo controle e o grupo CI + E2. O AACOCF3 foi um eficiente inibidor de PLA2 em sistema de cultura de células BEND e o E2 não estimulou a síntese de PKC e PLA2. No Experimento 2, novilhas Nelore cíclicas receberam 3 mg de 17ß-E2 (n = 6) ou nenhum tratamento (n = 5) no D17 e foram abatidas duas horas depois da administração dos tratamentos. A quantidade de PKC and PLA2 no tecido endometrial foi avaliada pela técnica de Western Blotting. Não foi observado efeito do E2 sobre a PKC (P= 0.08) e nem sobre a PLA2 (P= 0.56). Conclui-se que o E2 não estimulou a atividade e abundância de PKC e PLA2.(AU)
Assuntos
Animais , Bovinos , Proteína Quinase C , Bovinos/fisiologia , Inibidores de Fosfolipase A2 , Doenças Uterinas , Estradiol , Ionóforos de CálcioRESUMO
Abstract This review focuses on the innate immune events modulated by conceptus signaling during early pregnancy in ruminants. Interferon-tau (IFN-τ) plays a role in the recognition of pregnancy in ruminants, which involves more than the inhibition of luteolytic pulses of PGF2α to maintain corpus luteum function. For successful pregnancy establishment, the allogenic conceptus needs to prevent rejection by the female. Therefore, IFN-τ exerts paracrine and endocrine actions to regulate the innate immune system and prevent conceptus rejection. Additionally, other immune regulators work in parallel with IFN-τ, such as the pattern recognition receptors (PRR). These receptors are activated during viral and bacterial infections and in early pregnancy, but it remains unknown whether PPR expression and function are controlled by IFN-τ. Therefore, this review focuses on the main components of the innate immune response that are involved with early pregnancy and their importance to avoid conceptus rejection.
RESUMO
The release of endometrial prostaglandin-F2α (PGF2α) in bovine females can be induced in vivo by estradiol (E2). However, its role in this mechanism has not been clarified. We hypothesized that E2 stimulates the activity and abundance of protein kinase C (PKC) and phospholipase A2 (PLA2). Our objective in this study was to analyze the effects of PKC and PLA2 inhibitors on PGF2α synthesis induced by E2 and calcium ionophore (CI) in bovine endometrial cells (BEND cells; Experiment 1). Additionally, we evaluated the abundance of PKC and PLA2 in endometrial explants of cows treated or not with E2 17 days after estrus (D17, D0 = estrus; Experiment 2). In Experiment 1, BEND cells were submitted to a PKC inhibitor (10 µM of C25H24N4O2; bisindolylmaleimide I, or BIS I), a PLA2 inhibitor (20 µM of arachydoniltrifluoromethane or AACOCF3), or none. The BEND cells were subsequently treated with E2 and CI, and PGF2α concentrations were measured in the culture medium through radioimmunoassay. For DIF-12 (PGF2α concentration 12 h after treatment subtracted from PGF2α concentration at hour 0), no PKC inhibitor effect was observed (P= 0.2709). However, DIF-12 was lower (P < 0.05) for groups treated with the PLA2 inhibitor and PLA2 inhibitor + CI + E2 groups than the control and CI + E2 groups. Thus, AACOCF3 was an efficient PLA2 inhibitor in the BEND cells culture system, and E2 did not stimulate the synthesis of PKC and PLA2. In Experiment 2, cyclic Nellore heifers received none (n = 5) or 3 mg (n = 6) of 17ß-E2 on D17 and were slaughtered 2 h after administration. The abundance of PKC and PLA2 in the endometrial tissue was evaluated using Western blotting analysis. No E2 effect was observed on PKC (P = 0.08) and PLA2 (P = 0.56). We concluded that E2 did not stimulate the activity and abundance of PKC and PLA2.(AU)
A liberação endometrial de prostaglandina-F2α (PGF2α) em fêmeas bovinas pode ser induzida in vivo pelo estradiol (E2). Entretanto o seu mecanismo de ação ainda não foi bem esclarecido. Nossa hipótese é que o E2 estimula a atividade e a abundância da proteína quinase C (PKC) e da fosfolipase A2 (PLA2). Nosso objetivo com este estudo foi analizar os efeitos de inibidores de PKC e PLA2 na síntese de PGF2α induzida por E2 e ionóforo de cálcio (CI) em células endometriais bovinas (células BEND; Experimento 1). Adicionalmente, nós avaliamos a abundância de PKC e PLA2 em explantes endometriais de vacas tratadas com ou sem E2 17 dias após o estro (D17, D0 = estro; Experimento 2). No Experimento 1, células BEND foram submetidas ao inibidor de PKC (10 µM de C25H24N4O2; bisindolylmaleimide I, ou BIS I), e ao inibidor de PLA2 (20 µM de arachydoniltrifluoromethane ou AACOCF3) ou a nenhum inibidor. As células BEND foram subsequentemente tratadas com E2 e CI e concentrações de PGF2α foram mensuradas no meio de cultura por radioimunoenssaio. Para DIF-12 (concentração de PGF2α 12 horas depois do tratamento, subtraída da concentração de PGF2α na hora 0), não foi observado efeito do inibidor de PKC (P = 0.2709). Entretanto DIF-12 foi menor (P < 0.05) nos grupos tratados com inibidor de PLA2 e inibidor de PLA2 + CI + E2 quando comparados com o grupo controle e o grupo CI + E2. O AACOCF3 foi um eficiente inibidor de PLA2 em sistema de cultura de células BEND e o E2 não estimulou a síntese de PKC e PLA2. No Experimento 2, novilhas Nelore cíclicas receberam 3 mg de 17ß-E2 (n = 6) ou nenhum tratamento (n = 5) no D17 e foram abatidas duas horas depois da administração dos tratamentos. A quantidade de PKC and PLA2 no tecido endometrial foi avaliada pela técnica de Western Blotting. Não foi observado efeito do E2 sobre a PKC (P= 0.08) e nem sobre a PLA2 (P= 0.56). Conclui-se que o E2 não estimulou a atividade e abundância de PKC e PLA2.(AU)
Assuntos
Animais , Bovinos , Proteína Quinase C , Bovinos/fisiologia , Inibidores de Fosfolipase A2 , Doenças Uterinas , Estradiol , Ionóforos de CálcioRESUMO
Immune cells play a central role in early pregnancy establishment in cattle. We aimed to: (1) discover novel early-pregnancy-induced genes in peripheral blood mononuclear cells (PBMC); and (2) characterize the temporal pattern of early-pregnancy-induced transcription of select genes in PBMC and peripheral blood polymorphonuclear cells (PMN). Beef heifers were artificially inseminated on D0 and pregnancies were diagnosed on D28. On D10, 14, 16, 18, and 20, blood was collected for isolation of PBMC and PMN from heifers that were retrospectively classified as pregnant (P) or non-pregnant (NP). PBMC samples from D18 were submitted to RNAseq and 220 genes were differentially expressed between pregnant (P) and non-pregnant (NP) heifers. The temporal abundance of 20 transcripts was compared between P and NP, both in PBMC and PMN. In PBMC, pregnancy stimulated transcription of IFI6, RSAD2, IFI44, IFITM2, CLEC3B, OAS2, TNFSF13B, DMKN and LGALS3BP as early as D18. Expression of IFI44, RSAD2, OAS2, LGALS3BP, IFI6 and C1R in PMN was stimulated in the P group from D18. The novel early-pregnancy induced genes discovered in beef heifers will allow both the understanding of the role of immune cells during the pre-attachment period and the development of technologies to detect early pregnancies in beef cattle.
Assuntos
Leucócitos Mononucleares/metabolismo , Transcrição Gênica/genética , Animais , Bovinos , Feminino , Gravidez , Estudos RetrospectivosRESUMO
In cattle, conceptus development after elongation relies on well-characterized, paracrine interactions with the hosting maternal reproductive tract. However, it was unrecognized previously that the pre-hatching, pre-implantation bovine embryo also engages in biochemical signalling with the maternal uterus. Our recent work showed that the embryo modified the endometrial transcriptome in vivo. Here, we hypothesized that the embryo modulates the biochemical composition of the uterine luminal fluid (ULF) in the most cranial portion of the uterine horn ipsilateral to the corpus luteum. Endometrial samples and ULF were collected post-mortem from sham-inseminated cows and from cows inseminated and detected pregnant 7 days after oestrus. We used quantitative mass spectrometry to demonstrate that the pre-hatching embryo changes ULF composition in vivo. Embryo-induced modulation included an increase in concentrations of lipoxygenase-derived metabolites [12(S)-HETE, 15(S)-HETE] and a decrease in the concentrations of amino acids (glycine), biogenic amines (sarcosine), acylcarnitines and phospholipids. The changed composition of the ULF could be due to secretion or depletion of specific molecules, executed by either the embryo or the endometrium, but initiated by signals coming from the embryo. This study provides the basis for further understanding embryo-initiated modulation of the uterine milieu. Early embryonic signalling may be necessary to guarantee optimal development and successful establishment of pregnancy in cattle.
Assuntos
Blastocisto/metabolismo , Implantação do Embrião/genética , Desenvolvimento Embrionário/genética , Transcriptoma/genética , Aminoácidos/genética , Animais , Blastocisto/fisiologia , Bovinos , Corpo Lúteo/metabolismo , Implantação do Embrião/fisiologia , Endométrio/crescimento & desenvolvimento , Endométrio/metabolismo , Estro/genética , Estro/fisiologia , Feminino , Parto/genética , Parto/fisiologia , Gravidez , Prenhez , Útero/crescimento & desenvolvimento , Útero/metabolismoRESUMO
BACKGROUND: Xenotransplantation of spermatogonial stem cells (SSCs) has become a popular topic in various research fields because manipulating these cells can provide insights into the mechanisms associated with germ cell lines and the entire spermatogenesis process; moreover, these cells can be used in several biotechnology applications. To achieve successful xenotransplantation, the in vitro microenvironment in which SSCs are cultured should be an ideal microenvironment for self-renewal and similar to the in vivo testicular microenvironment. The age of the donor, the correct spermatogenesis cycle, and the quality of the donor tissue are also important. Although cell culture-related factors, such as the in vitro supplementation of hormonal factors, are known to promote successful xenotransplantation in mice, little is known about the influence of these factors on SSCs in vitro or in vivo in other mammalian species, such as dogs (Canis lupus familiaris). In this context, the goals of this study were to test the effect of follicle-stimulating hormone (FSH) on canine spermatogonial stem cell (cSSC) cultures since this hormone is related to the glial cell-derived neurotrophic factor (GDNF) signaling pathway, which is responsible for the self-renewal and maintenance of these cells in vivo, and to investigate the microenvironment of the SSC culture after FSH supplementation. Additionally, in vivo analyses of transplanted FSH-supplemented cSSCs in the testes of infertile mice were performed to assess the capacity of cSSCs to develop, maintain, and restore spermatogenesis. METHODS: SSCs from canine prepubertal testes (aged 3 months) were cultured in vitro in the presence of FSH (10 IU L-1). GFRA1 transcript expression was detected to confirm the spermatogonia population in culture and the effect of FSH on these cells. The protein and transcript levels of late germ cell markers (GFRA1, DAZL, STRA8, PLZF, and CD49f) and a pluripotency marker (OCT4) were detected at 72 and 120 h to confirm the cSSC phenotype. In vivo experiments were performed by transplanting GFP+ cSSCs into infertile mice, and a 10-week follow-up was performed. Histological and immunofluorescence analyses were performed to confirm the repopulation capacity after cSSC xenotransplantation in the testis. RESULTS: Supplementation with FSH in cell culture increased the number of cSSCs positive for GFRA1. The cSSCs were also positive for the pluripotency and early germline marker OCT4 and the late germline markers PLZF, DAZL, C-kit, and GFRA-1. The in vivo experiments showed that the cSSCs xenotransplanted into infertile mouse testes were able to repopulate germline cells in the seminiferous tubules of mice. CONCLUSIONS: In conclusion, our results showed for the first time that the treatment of cSSC cultures with FSH can promote in vitro self-renewal, increase the population of germline cells, and possibly influence the success of spermatogenesis in infertile mice in vivo.
Assuntos
Hormônio Foliculoestimulante/metabolismo , Espermatogênese/genética , Espermatogônias/transplante , Transplante Heterólogo/métodos , Animais , Cães , Masculino , Camundongos , Espermatogônias/citologiaRESUMO
Adaptation is a relevant characteristic to be understood in livestock animals in order to maintain and raise productivity. In Brazil, the Nellore beef cattle are widely disseminated and well-adapted breed that present good thermoregulatory characteristics for tropical environment conditions. Conversely, the physiological and cellular mechanisms required for thermoregulation and thermotolerance in this breed are still limited. The aim of this study was to comprehend the heat loss efficiency at the whole animal level and heat shock response at the cellular level of Nellore cows in tropical climate conditions. Healthy purebred Nellore cows were classified according to their capacity to lose body heat as Efficient or Inefficient based on vaginal temperature which was continuously monitored by data-loggers. Rectal, tail, and ocular temperatures, sweating rate, and respiratory frequency were collected to assess other thermoregulatory responses. Peripheral mononuclear cells were used for gene expression of heat shock proteins 60, 70, and 90 induced by in vitro heat treatments at 38, 40, and 42 °C. In our findings, the Efficient cows presented higher sweating rates compared to Inefficient cows that presented higher rectal temperature with greater amplitude of vaginal temperature profile. Transcription of the HSP genes was stable at 38 and 40 °C and decreased for all HSP genes at 42 °C. In conclusion, the Nellore efficiency to lose heat was mainly associated with their sweating capacity and cellular thermotolerance confirmed by the maintenance of heat shock proteins transcripts under heat stress. Taken together, this knowledge contributes as a future key for genetic selection of adapted animals.
Assuntos
Regulação da Temperatura Corporal , Clima Tropical , Animais , Brasil , Cruzamento , Bovinos , Feminino , Temperatura AltaRESUMO
The aim was to evaluate the associations between circulating P4 concentrations, corpus luteum (CL) size (diameter, area or volume) and blood perfusion (BP) in cows. In Experiment 1, Pearson's correlations (P < 0.05) with P4 concentrations were observed during CL development (D8) for total area (TA; r = 0.76), luteal area (ACL; r = 0.72), total and luteal diameter (TD and DCL respectively; r = 0.46). During mid-late diestrus, there was a positive correlation (P < 0.05) only at D15 with TA and ACL (r > 0.60), TD, total volume (TV) and luteal volume (VCL; r > 0.434). During luteal regression, the correlation was only observed at D18 for ACL (r = 0.478) and D20 with several variables. In Experiment 2, CL weight and ACL had the greatest correlation with P4 (r > 0.6). In Experiment 3, TA and ACL were the variables that were most closely correlated with serum P4 concentrations at D7 in recipient cows. Correlation coefficients were greater for luteal measurements when there were compact compared with cavitary CLs. In Experiment 4, there was no correlation (P > 0.05) between P4 and any of the variables measured on D4 and D7 in recipient cows detected in estrus. On D18 to D20, all CL characteristics were correlated (P < 0.05) with plasma P4, and luteal BP and BP area were more closely (P < 0.05) correlated than ACL. In conclusion, CL perimeter area measurements had the greatest association with luteal function during CL development; whereas for BP there was a greater correlation with P4 than luteal size during luteolysis.
Assuntos
Bovinos/fisiologia , Corpo Lúteo/anatomia & histologia , Ciclo Estral/fisiologia , Prenhez , Progesterona/sangue , Ultrassonografia/veterinária , Animais , Corpo Lúteo/fisiologia , Feminino , Ovulação , Gravidez , Prenhez/fisiologiaRESUMO
The working hypothesis was that supplementation with progesterone (iP4) at early diestrus increases pregnancy rates of suckled beef cows with poor body condition score (BCS) and/or in anestrus when cows are submitted to timed insemination (TAI). The time of ovulation among suckled multiparous (n = 1270) and primiparous (n = 303) Nelore cows was synchronized using an estradiol/P4-based protocol for TAI (D0). At Day â10, visual evaluation of BCS was performed (scale = 1-5) and animals were classified according to an ovarian activity (OA) score: (OA1) absence of CL and presence of follicles ≥ 8 mm, (OA2) absence of CL and presence of follicles < 8 mm and (OA3) presence of corpus luteum (CL). On Day 4, animals were assigned randomly to receive 150 mg of injectable, long-acting P4 (iP4, n = 786) or non-iP4 (n = 787). Further, ultrasonic evaluations were performed on D0 and D4 for measurements of the largest follicle diameter (DF) and CL area, respectively. The BCS affected positively DF, CL area and OA. Supplementation with iP4 did not affect (P = 0.49) pregnancy rates and there was no significant interaction (P > 0.1) of P4 treatment with BCS or OA was detected for conception and pregnancy rates. Regardless of iP4, pregnancy rates of cows with moderate (2.75-3.25) (59.1%) and high (≥ 3.5) (57.8%) BCS were greater than those of cows with low (2.0-2.5) BCS (41.5%). Cows in OA2 had a greater P/AI (51.3%) than cows in OA1 (41.7%) or OA3 (41.9%). In conclusion, P4 supplementation after TAI did not improve P/AI and did not enhance the response to treatment of cows with a low BCS, regardless of OA.
Assuntos
Constituição Corporal/fisiologia , Sincronização do Estro/métodos , Fertilidade , Inseminação Artificial , Ovário/efeitos dos fármacos , Ovulação , Progesterona/farmacologia , Animais , Constituição Corporal/efeitos dos fármacos , Bovinos , Preparações de Ação Retardada , Feminino , Fertilidade/efeitos dos fármacos , Fertilidade/fisiologia , Inseminação Artificial/métodos , Inseminação Artificial/veterinária , Ovário/fisiologia , Ovulação/efeitos dos fármacos , Ovulação/fisiologia , Gravidez , Taxa de Gravidez , Progesterona/administração & dosagem , Distribuição Aleatória , Projetos de PesquisaRESUMO
The intensive use of Doppler ultrasonography in several studies in the last decade allowed the characterization of vascular perfusion and the estimation of function of the reproductive organs and tissues along the estrous cycle and pregnancy in cattle. We aim to discuss the possibility of using Doppler imaging and to explore the potential of its inclusion in reproductive programs in cattle industry. Recent studies in dairy and beef cows indicated a high accuracy and sensitivity when Doppler ultrasonography is used to evaluate corpus luteum function and to diagnosis pregnancy between days 20 and 22. Moreover, resynchronization programs starting 5 to 7 days after timed embryo transfer (FTET) coupled with early pregnancy diagnosis were developed for beef cattle, and have been implemented in commercial embryo transfer programs. These strategies allow a reduction in the interval between two FTET from 40 to 24 days and may improve the gains in reproductive efficiency when compared to traditional programs than begin resynchronization after the pregnancy diagnosis at 30 days. A second alternative to use Doppler imaging is the evaluation of luteal blood perfusion at the time of embryo transfer for selection of recipients with greater receptivity potential. This may increases fertility in FTET, as embryos would not be transferred to females with non-functional CL, and in cases with recipients surplus, females with higher receptivity would be prioritized.(AU)
Assuntos
Animais , Feminino , Bovinos , Ultrassonografia Doppler , Ultrassonografia Doppler/veterinária , Bovinos , Transferência Embrionária , Transferência Embrionária/veterináriaRESUMO
The intensive use of Doppler ultrasonography in several studies in the last decade allowed the characterization of vascular perfusion and the estimation of function of the reproductive organs and tissues along the estrous cycle and pregnancy in cattle. We aim to discuss the possibility of using Doppler imaging and to explore the potential of its inclusion in reproductive programs in cattle industry. Recent studies in dairy and beef cows indicated a high accuracy and sensitivity when Doppler ultrasonography is used to evaluate corpus luteum function and to diagnosis pregnancy between days 20 and 22. Moreover, resynchronization programs starting 5 to 7 days after timed embryo transfer (FTET) coupled with early pregnancy diagnosis were developed for beef cattle, and have been implemented in commercial embryo transfer programs. These strategies allow a reduction in the interval between two FTET from 40 to 24 days and may improve the gains in reproductive efficiency when compared to traditional programs than begin resynchronization after the pregnancy diagnosis at 30 days. A second alternative to use Doppler imaging is the evaluation of luteal blood perfusion at the time of embryo transfer for selection of recipients with greater receptivity potential. This may increases fertility in FTET, as embryos would not be transferred to females with non-functional CL, and in cases with recipients surplus, females with higher receptivity would be prioritized.
Assuntos
Feminino , Animais , Bovinos , Bovinos , Transferência Embrionária , Transferência Embrionária/veterinária , Ultrassonografia Doppler , Ultrassonografia Doppler/veterináriaRESUMO
Prostaglandin F2α (PGF2α) determines luteolysis in cattle, and the ability to manipulate its endogenous synthesis is indispensible for large-scale animal breeding. Estradiol (E2) and progesterone (P4) modulate several molecular pathways in endometrial cells, including the synthesis of PGF2α; however, its specific mechanisms are still not totally known. This study investigated the production in vitro and possible modulation of endometrial PGF2α due to a local effect of endogenous E2 in the ipsilateral uterine horn (UH) containing the dominant follicle (DF) or from P4 in ipsilateral horn containing the corpus luteum (CL). The PGF2α stimulators oxytocin (OT) and phorbol 12,13-dibutyrate (PDBu) were incubated with endometrial explants, and PGF2α content was measured. For that, cycling cows were synchronized, the development of DF and CL was examined by ultrasonography and on the seventh day of the estrous cycle, endometrial explants were collected and cultured in medium supplemented with 10-6 M PDBu or 10-6 M OT or non-supplemented. Media samples were collected immediately after treatment and 60 min later. Radioimmunoassay showed that the PGF2α content of the UH ipsilateral to the DF was 49% less than that of the contralateral UH (8.22 ± 0.95 vs. 12.24 ± 0.95 pg/mL/mg tissue, respectively; P < 0.01). However, the PGF2α levels did not differ between the UHs as a function of the CL position (9.46 ± 0.95 vs. 11 ± 0.95 pg/mL/mg; P > 0.05). The cellular stimulators promoted an increase in PGF2α synthesis (P < 0.02), and the effects differed among the animals (P < 0.04). The PGF2a production was higher in the explants treated with PDBu rather than OT (13.68 ± 1.16 vs. 10.01 ± 1.16 pg/mL/mg tissue, respectively; P < 0.05). In conclusion, PGF2α synthesis is modulated by the presence of the DF (local E2) but not the CL (local P4), and both PDBu and OT stimulated PGF2a synthesis.(AU)
A prostaglandina F2α (PGF2α) determina a luteólise em bovinos. A capacidade de manipular sua síntese endógena é indispensável para a produção animal em grande escala. O estradiol (E2) e a progesterona (P4) modulam diversas vias moleculares das células endometriais, incluindo a síntese de PGF2α; no entanto, pouco se sabe sobre seus mecanismos específicos. Este trabalho investigou a produção in vitro e a possível modulação da PGF2α endometrial devido a um efeito local do E2 endógeno no corno uterino ipsilateral ao folículo dominante (FD) ou da P4 no corno ipsilateral ao corpo lúteo (CL). Os estimuladores de PGF2α oxitocina (OT) e 12,23-dibutirato de forbol (PDBu) foram incubados com explantes endometriais, e o conteúdo de PGF2α foi mensurado. Para tal, vacas cíclicas foram sincronizadas, o desenvolvimento de FD e CL foi examinado por ultrassonografia, e no 17º dia do ciclo estral os explantes endometriais foram coletados e cultivados em meio ou suplementados com PDBu 10-6M ou 10-6M OT. As amostras de meio foram coletadas imediatamente após o tratamento e sessenta minutos depois. O radioimunoensaio mostrou que o conteúdo de PGF2α do corno ipsilateral ao FD foi 49% menor que o do corno contralateral (8,22 ± 0,95 vs. 12,24 ± 0,95 pg/mL/mg de tecido, respectivamente, P < 0,01). No entanto, os níveis de PGF2α não diferiram entre os cornos em função da posição do CL (9,46 ± 0,95 versus 11 ± 0,95 pg/mL/mg; P > 0,05). Os estimuladores celulares promoveram um aumento na síntese de PGF2α (P < 0,02), e os efeitos diferiram entre os animais (P < 0,04). A produção de PGF2α foi maior nos explantes tratados com PDBu em comparação à OT (13,68 ± 1,16 versus 10,01 ± 1,16 pg/mL/mg de tecido, respectivamente, P < 0,05). A conclusão obtida foi que a síntese de PGF2α é: modulada pela presença do FD (E2 local), mas não do CL (P4 local); e estimulada por PDBu e OT.(AU)