RESUMO

While cryopreservation of cauda epididymal sperm (SpCau) allows the preservation of post-mortem bulls' gametes, the process triggers sperm damage. Although improving post-thaw sperm quality, using egg yolk extenders (EY) raises biosafety concerns which forces the use of EY-free extenders (EYFE). Since EYFE are less efficient in preserving post-thaw sperm quality, a strategy for ejaculated sperm (SpEj) frozen with EYFE is to add an Equilibrium Time (ET) step period to the cryopreservation process. However, the ET effect on the quality of SpCau cryopreserved in EYFE remains unknown. Distinct from SpEJ, SpCau physiologically displays cytoplasmic droplets (CDs) in the flagellum that may benefit cell exchange during ET. We hypothesized that using ET in SpCau cryopreserved with EYFE impacts sperm morphofunctional features, CD area, and in vitro fertility ability. Extender nanoparticles were also assessed. Following collection from the cauda epididymis of six Nellore bulls by retrograde flow, SpCau were cryopreserved in EYFE BoviFree® (Minitube, Germany) using three ET protocols: ET0 (no-ET); ET2.5 (2.5 h-ET); and ET5 (5 h-ET). SpCau from ET2.5 and ET5 showed a higher (P ≤ 0.05) percentage of motility and integrity of plasma and acrosome membranes and a smaller (P ≤ 0.05) distal CD area. There are no differences in sperm abnormalities, oxidative stress, capacitation-like events, and in vitro fertility ability. However, a better sperm recovery was found after Percoll® selection for ET2.5 and ET5. Interestingly, the number of nanoparticles in the extender decreased in post-thawed samples. In conclusion, an ET of 2.5 or 5 h is required for an efficient SpCau cryopreservation using an EYFE.

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RESUMO

Por ser uma célula altamente especializada, o espermatozoide apresenta diferentes mecanismos epigenéticos, sendo os principais as metilações do DNA, o código de histonas, os ncRNAs (RNAs não codificadores), e a alta condensação da cromatina pela presença das protaminas. Estes mecanismos interagem entre si, contribuindo para a formação do epigenoma espermático, que modela a carga molecular espermática, que, por sua vez, pode impactar sobre as características do desenvolvimento embrionário e da progênie. Dessa forma, atualmente é consenso que o papel do espermatozoide ultrapassa a entrega de DNA de qualidade para o oócito no momento da fecundação. Pesquisas recentes de diversos grupos, incluindo o nosso, mostram que além da contribuição com DNA de qualidade, o espermatozoide entrega moléculas ao oócito no momento da fecundação que influenciam o desenvolvimento do embrião. Recentemente, essas moléculas de origem espermática (Em inglês: sperm-borne) também são associadas com alterações metabólicas e cognitivas da progênie. Embora ainda pouco se entenda como esses mecanismos podem persistir mesmo com o ciclo de reprogramação celular que ocorre logo após a fecundação, é evidente que estes podem impactar as características da progênie. Nesta revisão abordaremos sobre a modulação do epigenoma espermático e seus efeitos no desenvolvimento embrionário.(AU)

Since it is a highly specialized cell, the spermatozoa display different epigenetic mechanisms; the main ones are DNA methylation, histone code, ncRNAs (non-coding RNAs), and high chromatin condensation by the presence of protamines. These mechanisms act in synergy contributing to forming the sperm epigenome, which modulates the spermatic molecular cargo, and, may impact embryo and offspring development features. Thus, it is currently a consensus that the role of spermatozoa goes beyond delivering quality DNA to the oocyte at fertilization. Relevant findings from several research groups, including ours, have shown that sperm delivers several molecules to the oocyte at fertilization, beyond the contribution to DNA, which influences the development of the embryo. Recently, these sperm-borne molecules have also been associated with metabolic and cognitive changes in the offspring. Although the mechanism by which these changes can persist even after embryo reprogramming is not completely understood, evidence shows that sperm cell molecular content impacts embryo and offspring development. This review will mainly focus on the modulation of the sperm epigenome and its effects on embryo development.(AU)

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RESUMO

Since buffaloes are a seasonal, polyestrous species, optimizing reproduction during the non-breeding season is a key factor in increasing the reproductive and productive efficiency of herds. Ovum pick-up associated with in vitro embryo production and embryo cryopreservation is an alternative to reduce seasonal impacts. We studied the effects of seasonality in buffalo oocyte donors and embryo recipients during the favorable and non-favorable breeding seasons. Donors were evaluated for oocyte recovery and blastocyst production rate as dFBS (donors in favorable breeding season) or dNBS (donors in non-favorable breeding season). Embryos produced from dFBS or dNBS were cryopreserved by vitrification or the slow-freeze method for direct transfer and transferred to recipients in the favorable (rFBS) or non-favorable breeding season (rNBS). The heifers or cows were subjected to a fixed-time embryo transfer protocol and conception rates were determined on day 30 and on day 60. The oocyte recovery was lower in dFBS than in dNBS (7.6 vs. 10.0 oocyte/OPU, p = 0.0262); while no difference was found comparing blastocyst production rate (23.7% vs. 30.9% of blastocysts, respectively). Embryos from dFBS resulted in greater (p = 0.0013) conception rates on day 30 compared to dNBS (46.5% vs. 22.4%, respectively), despite the breeding season. The rFBS and rNBS treatments had similar (p = 0.6714) conception rates on day 30 (38.0% vs. 33.0%, respectively), indicating similar uterine receptivity. However, heifers on FBS had higher (p = 0.0003) conception rates on day 30 than cows (73.9% vs. 13.3%, respectively) when receiving embryos from dFBS. Vitrification and direct transfer had similar (p = 0.1698) conception rates on day 30 (30.4% vs. 41.4%, respectively). In conclusion, in vitro-produced embryos derived from dFBS were more competent in establishing pregnancy than dNBS counterparts, independent of recipients' reproductive seasonality. Heifers achieved better conception rates than cows during the favorable breeding season when the embryo came from dFBS. Cryopreserved in vitro produced embryos represent a reliable alternative to reduce seasonal variations in buffalo reproduction. The data elucidate the seasonal effects on embryo competence and on recipients' uterine receptivity, affording new strategies to implement ovum pick-up associated with in vitro embryo production programs in buffalo herds.

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RESUMO

Detection of reactive oxygen species (ROS) is of great interest in semen analysis since their excess is detrimental to sperm function and male fertility. Fluorescence microscopy has achieved attention for providing broad possibilities of sperm evaluations and also for presenting substantial accessibility. In this context, this study investigated the efficiency of CellROX Deep Red® and Orange® probes in detecting ROS in bovine sperm cells and assessed their relationship with sperm fertility potential. First, 16 ejaculates were assigned in three treatments: T0 (no ROS production induced), T1x (ROS production induced once) and T2x (ROS production induced twice). Samples were incubated with Red and Orange probes and percentages of cells producing ROS were evaluated using fluorescence microscopy. Coefficient of determination was 0.61 for Red and 0.56 for Orange. Afterwards, frozen-thawed semen samples from high and low fertility bulls were evaluated regarding percentages of cells producing ROS detected by Red and Orange. Higher levels of ROS assessed by Red were detected in low fertility bovine samples. In conclusion, CellROX Red® and Orange® are both efficient in detecting ROS in bovine spermatozoa. Furthermore, higher sperm ROS detection by CellROX Red® might be associated with low fertility samples.

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RESUMO

Testicular heat stress affects sperm quality and fertility. However, the chronology of these effects is not yet fully understood. This study aimed to establish the early sequential effects of heat stress in bull sperm quality. Semen and blood samples of Nellore breed bulls were collected and distributed into control and testicular heat stress (scrotal bags/96 h) groups. Semen samples were evaluated for sperm motility, abnormalities, plasma membrane integrity, acrosomal membrane integrity, mitochondrial membrane potential, sperm lipid peroxidation, seminal plasma lipid peroxidation, and DNA fragmentation. Blood plasma was also evaluated for lipid peroxidation. An increase in sperm abnormalities was observed 7 days following heat stress. After 14 days, sperm lipid peroxidation increased and mitochondrial membrane function, sperm motility, and plasma membrane integrity decreased. Heat stress effects were still observed after 21 days following heat stress. An increase in sperm DNA fragmentation was observed as a late effect after 28 days. Thus, the initial effects of heat stress (i.e., increasing sperm abnormalities and lipid peroxidation) suggest the presence of oxidative stress in the semen that alters mitochondrial function, sperm motility, plasma membrane integrity, and belatedly, DNA fragmentation. Although sperm abnormalities persisted and increased over time, sperm lipid peroxidation, in turn, increased only until 21 days after heat stress. In this regard, these findings provide a greater understanding of the chronological effects of experimentally induced heat stress on bovine sperm, providing valuable insights about spermatogenesis during the first 28 days following heat stress.

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Semen freezability is positive correlated with the cholesterol content in the sperm cell. Freeze-thawing mainly cause temperature chock and change on media osmolarity, which can modify plasma membrane lipids content and sperm conformation, resulting in decreased fertility. Therefore, the aim of this study is to investigate the effect of adding cholesterol-loaded cyclodextrin (CLC) to the cryopreservation process of ram semen with low freezability. For that, two experiments were performed using 5 ejaculates of 6 rams, totalizing 30 samples. For experiment 1 the following treatments were tested: in natura (IN), Tris solution (CON), CLC + Tris solution (CLC), and pure methyl-ß-cyclodextrin + Tris solution (MCD). For experiment 2 treatments CON and CLC were tested in samples subdivided into three freezability classes: high (n = 10), intermediate (n = 10) and low (n = 10). Freezability classes were based on the variation of sperm motility between IN and CON groups from the first experiment. Sample analyzes included sperm motility, sperm morphology, plasma and acrosome membrane integrity, mitochondrial membrane potential, reactive oxygen species content, lipid peroxidation, and fluidity of plasma membrane. Results showed that CLC treatment was more efficient in maintaining sperm motility, integrity of plasma membrane, integrity of acrosome, and mitochondria membrane potential. In addition, CLC treatment in the groups with low and intermediate freezability showed improvement on progressive motility and percentage of rapid cells. In contrast, no difference was noted between CLC and CON treatments in the high freezability group. Therefore, the addition of CLC to semen extender improved sperm cryopreservation, especially in rams with low freezability.

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RESUMO

Stress at the end of sheep gestation can damage the reproductive development of young males. The aim of the present study was to evaluate the effects of LPS administration in the last third of sheep pregnancy on the reproductive parameters of prepubertal rams. Thirty-six pregnant nulliparous ewes (12 ±â€¯2 months old; 45 ±â€¯6 kg) were assigned to two treatments, LPS (E. coli; 0.8 µg kg-1) and control (placebo/saline) administered in late pregnancy (120 days post-conception). The animals gave birth to 17 male lambs (11 LPS; 8 control). Reproductive development of the young rams was analyzed from 5 to 12 months of age. A completely randomized design in double factorial scheme was used. The data were analyzed by analysis of variance. The model included treatment (LPS; control), age as main effects and their interactions, and the animal as a repeated measure. Means were compared by the PDIFF-SAS (Pr > |t|) at P < 0.05. An effect of age was observed for scrotal circumference, testicular consistency, homogeneity of testicular parenchyma, vascularization, semen quantity and quality, and blood testosterone concentration (P < 0.05). LPS increased sperm defects (P < 0.05) but an interaction with age was not observed (P > 0.05) with higher abnormalities only during months 8 and 9 (P < 0.05) and not thereafter. In summary, LPS did not cause long-term damage to testicular morphology analyzed from the onset of puberty to sexual maturity. However, LPS treatment affected sperm morphology during early puberty of the offspring.

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RESUMO

Semen fertilizing potential is dependent upon the morphological, functional and molecular attributes of sperm. Sperm microRNAs (miRNAs) were recently shown to hold promise regarding their association with different fertility phenotypes. However, their role in fertility regulation remains to be determined. We postulated that sperm miRNAs might regulate early embryonic development. From this perspective, sperm quality and 380 sperm miRNAs were investigated in frozen-thawed semen from high (HF; 54.3 ± 1.0% pregnancy rate) and low (LF; 41.5 ± 2.3%) fertility bulls. Out of nine miRNAs that showed different levels in sperm cells, miR-216b was present at lower levels in HF sperm cells and zygotes. Among miR-216b target genes (K-RAS, BECN1 and JUN), K-RAS, related to cell proliferation, revealed a higher level in HF two-cell embryos. First cleavage rate, blastocyst cell number and division number were also higher in HF. In addition, by using a model based on polyspermy embryos, we demonstrated an increase in miR-216b levels in zygotes associated with sperm cell entry. Our results shed light on a possible mechanism of paternal contribution involving sperm-borne miR-216b that modulates levels of miR-216b in zygotes and K-RAS in two-cell embryos. This modulation might regulate early development by interfering with the first cleavage and blastocyst quality.

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RESUMO

Low-level laser therapy (LLLT) can modulate redox state of the cell which could be useful to treat testicular degeneration and also prevent injuries by sperm cryopreservation. The aim of this study was to evaluate the effects of LLLT treatment on semen cryopreservation from rams submitted or not to testicular degeneration by testicular insulation. Eleven White Dorper rams were divided into four groups: animals that were not insulated (Control) and not treated (No Laser) (n = 2); animals that were not insulated and treated with LLLT (n = 3); animals that were insulated and not treated with LLLT (n = 3), and animals that were insulated and treated with LLLT (n = 3). Testicular insulation was performed using scrotal insulation bags for 72 h. LLLT treatment was 28 J/cm2 energy, 808 nm of wavelength, and 30 mW of power output, irradiated on testis for 15 days with an interval of 48 h. Three ejaculates from each ram were collected: before insulation, 23, and 59 days after insulation bag removal. Cryopreservation was performed of the third ejaculate. Sperm evaluation was performed before and after cryopreservation considering sperm motility, morphology, acrosomal and plasma membrane integrity, mitochondrial potential, and oxidative stress. As expected, cryopreservation had a negative effect on several sperm motility characteristics and sperm membranes. LLLT treatment did not improve sperm quality from rams submitted to testicular insulation. Thus, testicular insulation and cryopreservation effects on spermatozoa were not attenuated by LLLT in this study.

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RESUMO

Considering the importance of ROS influence on sperm functionality and some limitations in sperm oxidative stress assessment methods, a field to studies of new techniques are still open. In this sense, the aim of this study is to validate the ROS detection technique through the CellRox Deep Red Reagent®probe in stallion sperm. Four stallions were used and the analyses were conducted on four replicates of semen samples from each of stallion (n = 16). The results of the polynomial regression presented a quadratic effect, high determination coefficient value (R2 = 0.88) and high significant P value (P < 0.0001). The CellRox Deep Red® fluorescent probe is able to detect reactive oxygen species in equine sperm, indicating accurately the occurrence of oxidative stress in stallion semen.(AU)

Assuntos

RESUMO

Considering the importance of ROS influence on sperm functionality and some limitations in sperm oxidative stress assessment methods, a field to studies of new techniques are still open. In this sense, the aim of this study is to validate the ROS detection technique through the CellRox Deep Red Reagent®probe in stallion sperm. Four stallions were used and the analyses were conducted on four replicates of semen samples from each of stallion (n = 16). The results of the polynomial regression presented a quadratic effect, high determination coefficient value (R2 = 0.88) and high significant P value (P < 0.0001). The CellRox Deep Red® fluorescent probe is able to detect reactive oxygen species in equine sperm, indicating accurately the occurrence of oxidative stress in stallion semen.

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RESUMO

A fertilização envolve um processo complexo e requer muitos atributos espermáticos para seu sucesso.Há uma grande variação no sêmen de diferentes touros e partidas, o que causa uma oscilação no potencial defertilidade. A inseminação artificial em tempo fixo (IATF) utilizando partidas de sêmen com reduzido potencialde fertilidade causa um grande impacto na produtividade do rebanho. Partidas de sêmen que apresentamcaracterísticas de motilidade progressiva, vigor, defeitos morfológicos e concentração dentro das aceitáveis parao uso na IA podem mostrar deficiência no potencial de fertilidade, o que pode ser atribuído a alterações emestruturas ou funções espermáticas não contempladas nestas avaliações. Várias técnicas vêm sendodesenvolvidas buscando a identificação de alterações espermáticas que resultam em falha na fertilidade;revelando com mais precisão lesões nas células espermáticas após o processo de criopreservação. Este texto visaabordar, baseados principalmente em nossas experiências, as falhas de fertilidade inerentes ao sêmen e o quantoas técnicas laboratoriais podem predizer sobre o potencial de fertilidade de uma partida de sêmen antes do uso naIATF e seu impacto sobre a fertilidade do rebanho.

Fertilization involves a complex process and requires many sperm attributes for its success. There isgreat variation in the semen of different bulls and batch, which causes an oscillation in fertility potential. Theuse in TAI of semen batch with reduced fertility potential causes a great impact on the productivity of the herd.Semen batches that exhibit characteristics of progressive motility, vigor, morphological defects andconcentration within those acceptable for use in AI may show reduction in fertility potential, which may beattributed to changes in structures or sperm functions not contemplated in these evaluations. Several techniqueshave been developed to identify sperm alterations that result in failure of fertility; revealing more accuratelysperm cell lesions after the cryopreservation process. This paper aims to address, essentially based on ourexperiences, fertility failures inherent to semen and how laboratory techniques can predict the fertility potentialof a semen batch prior to use in TAI and its impact on herd fertility.

Assuntos

RESUMO

Atualmente, a predição da fertilidade masculina é realizada avaliando diversos aspectosmorfofuncionais (MFF) espermáticos. Em geral, estas características MFF possuem alta correlação com afertilidade. No entanto, existem ejaculados que embora possuam características MFF consideradas adequadasapresentam fertilidade insatisfatória. Assim, há demanda pela busca de novos marcadores que consigam predizera fertilidade dessas amostras seminais. Dentre estes, estão os microRNAs (miRNAs), reguladores póstranscricionais,que desempenham funções importantes na espermatogênese, na maturação espermática e nodesenvolvimento embrionário. Estudos com humanos e bovinos têm mostrado que essas moléculas possuemrelação com a fertilidade. Além disso, já foi descrito também que os miRNAs são altamente regulados nosistema reprodutivo masculino, e principalmente, ao longo da cabeça, corpo e cauda do epidídimo. Atualmenteexistem mais de 790 sequências maduras de miRNAs conhecidas em bovinos e o estabelecimento destes comomarcadores se torna cada vez mais real. Entretanto, o grande desafio destes estudos está em mostrar como estesmiRNAs efetivamente regulam a fertilidade e qual o papel deles nas funções espermáticas e no desenvolvimentoembrionário. Dessa forma, o objetivo desta revisão é compilar os dados existentes na literatura sobre os miRNAse a fertilidade masculina.

Fertility prediction is performed evaluating several sperm morphological and functional aspects(MFF). In general, MFF features present high correlation with fertility. However, there are ejaculates that,although present normal MFF features, have poor fertility results. So, there is necessity to investigate potentialfertility molecular markers which are able to predict fertility rates. Among them are the microRNAs (miRNAs),which are post-transcriptional regulators molecules that are important to spermatogenesis, sperm maturationand also embryo development. Besides, miRNAs are related with men and bull fertility and are highly regulatedon masculine tract. Currently, there are around 790 mature miRNA sequences in bovine, which could be used asbiomarkers. Nevertheless, the big challenge is to show how miRNAs regulate fertility and their functions onsperm and embryo development. Thus, the goal of this review is to compile the data of scientific literature aboutmiRNAs and male fertility.

Assuntos

RESUMO

As condições do trato reprodutivo da fêmea, a qualidade do sêmen e os diversos eventos físicos ebioquímicos que os gametas passam até a fecundação são alguns dos fatores que influenciam a fertilidade.Muitos estudos estão sendo realizados na busca de reconhecer todos estes fatores e suas interações, e todos como objetivo de aumentar a taxa de fertilidade. Na resposta inflamatória fisiológica e transitória que ocorre após adeposição do sêmen no útero das éguas, há liberação de mediadores quimiotáticos e migração de célulaspolimorfonucleares (PMN). Tal processo é desencadeado pelos espermatozoides, microrganismos ecomponentes dos diluidores. Este processo precisa ser debelado para restabelecer as condições uterinas normaisquando da chegada do embrião. No entanto, acredita-se que a deposição de sêmen de baixa qualidade, ou seja,com mais espermatozoides lesados, aumenta a resposta inflamatória. Desta forma, o objetivo desta revisão éestabelecer a importância das interações entre a qualidade do sêmen e a resposta inflamatória uterina em éguas,com o intuito de reconhecer seus efeitos sobre a fertilidade.

The conditions of the female reproductive tract, the quality of the semen and the various physical andbiochemical events that the gametes pass through to fertilization are some of the factors that influence fertility.Many studies are being conducted in the quest to recognize all these factors and their interactions, and all withthe aim of increasing the fertility rate. In the physiological and transient inflammatory response that occurs afterthe deposition of semen in the uterus of mares, there is release of chemotactic mediators and migration ofpolymorphonuclear cells (PMN). Such a process is triggered by spermatozoa, microorganisms and diluentcomponents. This process must be terminated to restore normal uterine conditions upon the arrival of theembryo. However, it is believed that the deposition of low quality semen, that is, with more spermatozoadamaged, increases the inflammatory response. Thus, the purpose of this review is to establish the importance ofthe interactions between semen quality and the uterine inflammatory response in mares, in order to recognize itseffects on fertility.

Assuntos

RESUMO

A fertilização envolve um processo complexo e requer muitos atributos espermáticos para seu sucesso.Há uma grande variação no sêmen de diferentes touros e partidas, o que causa uma oscilação no potencial defertilidade. A inseminação artificial em tempo fixo (IATF) utilizando partidas de sêmen com reduzido potencialde fertilidade causa um grande impacto na produtividade do rebanho. Partidas de sêmen que apresentamcaracterísticas de motilidade progressiva, vigor, defeitos morfológicos e concentração dentro das aceitáveis parao uso na IA podem mostrar deficiência no potencial de fertilidade, o que pode ser atribuído a alterações emestruturas ou funções espermáticas não contempladas nestas avaliações. Várias técnicas vêm sendodesenvolvidas buscando a identificação de alterações espermáticas que resultam em falha na fertilidade;revelando com mais precisão lesões nas células espermáticas após o processo de criopreservação. Este texto visaabordar, baseados principalmente em nossas experiências, as falhas de fertilidade inerentes ao sêmen e o quantoas técnicas laboratoriais podem predizer sobre o potencial de fertilidade de uma partida de sêmen antes do uso naIATF e seu impacto sobre a fertilidade do rebanho.(AU)

Fertilization involves a complex process and requires many sperm attributes for its success. There isgreat variation in the semen of different bulls and batch, which causes an oscillation in fertility potential. Theuse in TAI of semen batch with reduced fertility potential causes a great impact on the productivity of the herd.Semen batches that exhibit characteristics of progressive motility, vigor, morphological defects andconcentration within those acceptable for use in AI may show reduction in fertility potential, which may beattributed to changes in structures or sperm functions not contemplated in these evaluations. Several techniqueshave been developed to identify sperm alterations that result in failure of fertility; revealing more accuratelysperm cell lesions after the cryopreservation process. This paper aims to address, essentially based on ourexperiences, fertility failures inherent to semen and how laboratory techniques can predict the fertility potentialof a semen batch prior to use in TAI and its impact on herd fertility.(AU)

Assuntos

RESUMO

As condições do trato reprodutivo da fêmea, a qualidade do sêmen e os diversos eventos físicos ebioquímicos que os gametas passam até a fecundação são alguns dos fatores que influenciam a fertilidade.Muitos estudos estão sendo realizados na busca de reconhecer todos estes fatores e suas interações, e todos como objetivo de aumentar a taxa de fertilidade. Na resposta inflamatória fisiológica e transitória que ocorre após adeposição do sêmen no útero das éguas, há liberação de mediadores quimiotáticos e migração de célulaspolimorfonucleares (PMN). Tal processo é desencadeado pelos espermatozoides, microrganismos ecomponentes dos diluidores. Este processo precisa ser debelado para restabelecer as condições uterinas normaisquando da chegada do embrião. No entanto, acredita-se que a deposição de sêmen de baixa qualidade, ou seja,com mais espermatozoides lesados, aumenta a resposta inflamatória. Desta forma, o objetivo desta revisão éestabelecer a importância das interações entre a qualidade do sêmen e a resposta inflamatória uterina em éguas,com o intuito de reconhecer seus efeitos sobre a fertilidade.(AU)

The conditions of the female reproductive tract, the quality of the semen and the various physical andbiochemical events that the gametes pass through to fertilization are some of the factors that influence fertility.Many studies are being conducted in the quest to recognize all these factors and their interactions, and all withthe aim of increasing the fertility rate. In the physiological and transient inflammatory response that occurs afterthe deposition of semen in the uterus of mares, there is release of chemotactic mediators and migration ofpolymorphonuclear cells (PMN). Such a process is triggered by spermatozoa, microorganisms and diluentcomponents. This process must be terminated to restore normal uterine conditions upon the arrival of theembryo. However, it is believed that the deposition of low quality semen, that is, with more spermatozoadamaged, increases the inflammatory response. Thus, the purpose of this review is to establish the importance ofthe interactions between semen quality and the uterine inflammatory response in mares, in order to recognize itseffects on fertility.(AU)

Assuntos

RESUMO

Atualmente, a predição da fertilidade masculina é realizada avaliando diversos aspectosmorfofuncionais (MFF) espermáticos. Em geral, estas características MFF possuem alta correlação com afertilidade. No entanto, existem ejaculados que embora possuam características MFF consideradas adequadasapresentam fertilidade insatisfatória. Assim, há demanda pela busca de novos marcadores que consigam predizera fertilidade dessas amostras seminais. Dentre estes, estão os microRNAs (miRNAs), reguladores póstranscricionais,que desempenham funções importantes na espermatogênese, na maturação espermática e nodesenvolvimento embrionário. Estudos com humanos e bovinos têm mostrado que essas moléculas possuemrelação com a fertilidade. Além disso, já foi descrito também que os miRNAs são altamente regulados nosistema reprodutivo masculino, e principalmente, ao longo da cabeça, corpo e cauda do epidídimo. Atualmenteexistem mais de 790 sequências maduras de miRNAs conhecidas em bovinos e o estabelecimento destes comomarcadores se torna cada vez mais real. Entretanto, o grande desafio destes estudos está em mostrar como estesmiRNAs efetivamente regulam a fertilidade e qual o papel deles nas funções espermáticas e no desenvolvimentoembrionário. Dessa forma, o objetivo desta revisão é compilar os dados existentes na literatura sobre os miRNAse a fertilidade masculina.(AU)

Fertility prediction is performed evaluating several sperm morphological and functional aspects(MFF). In general, MFF features present high correlation with fertility. However, there are ejaculates that,although present normal MFF features, have poor fertility results. So, there is necessity to investigate potentialfertility molecular markers which are able to predict fertility rates. Among them are the microRNAs (miRNAs),which are post-transcriptional regulators molecules that are important to spermatogenesis, sperm maturationand also embryo development. Besides, miRNAs are related with men and bull fertility and are highly regulatedon masculine tract. Currently, there are around 790 mature miRNA sequences in bovine, which could be used asbiomarkers. Nevertheless, the big challenge is to show how miRNAs regulate fertility and their functions onsperm and embryo development. Thus, the goal of this review is to compile the data of scientific literature aboutmiRNAs and male fertility.(AU)

Assuntos

RESUMO

Reestablishment of testicular normal temperature after testicular heat stress is unknown and its effect varies widely. The aim of this study was to investigate the impact of scrotal insulation (IN) on testicular temperature and its relation to semen quality and testosterone blood serum concentration. For this, 33 rams were used; 17 submitted to IN for 72 hours (using bags involving the testes) and 16 not submitted to IN (control group). The experiment was performed between August and December 2013 in Pirassununga, Brazil (21°56″13″ South/47°28'24″ West). Seminal characteristics, testosterone blood serum concentration, rectal temperature (RT), respiratory frequency, scrotal superficies mean temperature (SSMT), and eye area mean temperature (EAMT) were analyzed 7 days before IN and 21, 35, 49, 63, and 90 days afterward. Scrotal superficies mean temperature and EAMT were measured by thermography camera FLIR T620. Testosterone was evaluated by radioimmunoassay. Analysis of variance was used to determine the main effects of treatment, time, and treatment-by-time interaction using PROC MIXED of SAS software adding command REPEAT. Pearson correlation test was used to verify correlation between SSMT, EAMT, RT, and respiratory frequency. Significant difference was considered when P ≤ 0.05. At the end of IN, SSMT was higher (P < 0.05) in insulated group (32.26 ± 0.19(o)C) than in control group (30.58 ± 0.18(o)C), and the difference between rectal and testicular (deduced from SSMT) temperatures was 1.12 °C; in the other times of the evaluation this difference was between 2.91 and 4.25 °C in IN group. Scrotal superficies mean temperature was reestablished 24 hours after IN. Rectal temperature and EAMT presented correlation (r = 0.59; P < 0.0001). There was time-by-treatment interaction for total sperm (P = 0.0038) and progressive motility (P = 0.01), abnormal spermatozoa (P < 0.0001), membranes integrity (P < 0.0001), induced thiobarbituric acid reactive substances (TBARSs; P = 0.05), and DNA integrity (P = 0.0004). These semen characteristics were negatively affected 21 days after IN, and excluding induced TBARSs and abnormalities, recovered 35 days afterward; induced TBARSs just were affected after 49 days of IN; sperm abnormalities just recovered after 63 days. Testosterone blood serum concentration was lesser in insulated rams (P = 0.03). Thus, the difference of 1.12 °C between RT and testicular temperature impacts semen quality and testosterone blood serum concentration. Moreover, this study shows that rams can recover testes temperature efficiently toward IN and that infrared thermography is an efficient tool to identify differences on SSMT.

Assuntos

RESUMO

The aim of this study was to investigate the efficiency of low-level laser therapy (LLLT) to recovery testicular degeneration in rams. In the first study, rams were induced to testicular degeneration by scrotal insulation, and then, they were treated using LLLT at 28 J/cm(2) (INS28) or 56 J/cm(2) (INS56) energy densities. Sperm kinetics, morphology, and membranes integrity as well as proportion of lumen area in seminiferous tubule were assessed. In the second study, rams were submitted or not to scrotal insulation and treated or not by the best protocol of LLLT defined by experiment 1 (INS28). In this study were evaluated sperm kinetics, morphology, membranes integrity, ROS production, and DNA integrity. Testosterone serum concentration and proportion of lumen area in seminiferous tubule were also analyzed. Insulation was effective in promoting sperm injuries in both experiments. Biostimulatory effect was observed in experiment 1: INS28 presented smaller proportion of lumen area (P = 0.0001) and less degeneration degree (P = 0.0002). However, in experiment 2, there was no difference between the groups (P = 0.17). In addition, LLLT did not improve sperm quality, and there was a decreasing for total and progressive motility (P = 0.02) and integrity of sperm membranes (P = 0.01) in LLLT-treated groups. Moreover, testosterone concentration was not improved by LLLT (P = 0.37). Stimulation of aerobic phosphorylation by LLLT may have led to a deregulated increase in ROS leading to sperm damages. Thus, LLLT at energy of 28 J/cm(2) (808 nm of wavelength and 30 mW of power output) can induce sperm damages and increase the quantity of cells in seminiferous tubule in rams.

Assuntos