RESUMO
Although there are several studies on morphogenesis in Teleostei, until now there is no research describing the role of the basement membrane in the establishment of the germinal epithelium during gonadal differentiation in Characiformes. In attempt to study these events that result in the formation of ovarian and testicular structures, gonads of Gymnocorymbus ternetzi were prepared for light microscopy. During gonadal development in G. ternetzi, all individuals first developed ovarian tissue. The undifferentiated gonad was formed by somatic cells (SC) and primordial germ cells (PGCs). After successive mitosis, the PGCs became oogonia, which entered into meiosis originating oocytes. An interstitial tissue developed. In half of the individuals, presumptive female, prefollicle cells synthesized a basement membrane around oocyte forming a follicle. Along the ventral region of the ovary, the tissue invaginated to form the ovigerous lamellae, bordered by the germinal epithelium. Stroma developed and the follicle complexes were formed. The gonadal aromatase was detected in interstitial cells in the early steps of the gonadal differentiation in both sexes. In another half of the individuals, presumptive male, there was no synthesis of basement membrane. The interstitium was invaded by numerous granulocytes. Pre-Leydig cells proliferated. Apoptotic oocytes were observed and afterward degenerated. Spermatogonia appeared near the degenerating oocytes and associated to SCs, forming testicular tubules. Germinal epithelium developed and the basement membrane was synthesized. Concomitantly, there was decrease of the gonadal aromatase and increase in the 3ß-HSD enzyme expression. Thus, the testis was organized on an ovary previously developed, constituting an indirect gonochoristic differentiation.
Assuntos
Membrana Basal/anatomia & histologia , Characidae/anatomia & histologia , Transtornos do Desenvolvimento Sexual/patologia , Gônadas/anatomia & histologia , Diferenciação Sexual , Fatores Etários , Animais , Membrana Basal/citologia , Feminino , Gônadas/citologia , Masculino , OrganogêneseRESUMO
We are describing a rhabdom organization of the eye of the chrysanthemum beetle Phytoecia rufiventris that to date has not been described from any other insect. In cerambycid beetles free rhabdomeres, forming a circular, open rhabdom, surround a central rhabdom made up of the rhabdomeres of one or two cells. In Phytoecia rufiventris the central rhabdomeres are missing throughout the eye and the microvilli of the outer 6 rhabdomeres are regularly oriented in three directions. Following the classification of rhabdom types suggested by Wachmann (1979), we suggest to name the rhabdom arrangement seen in the retina of Phytoecia rufiventris [quot ]Grundmuster 3[quot ]. This pattern ought to facilitate polarization sensitivity and movement perception, features that agree with the behavioural repertoire of Phytoecia rufiventris.
Assuntos
Animais , Besouros/anatomia & histologia , Besouros/fisiologia , Membrana Basal/citologia , Membrana Basal , Olho/anatomia & histologia , Olho/citologia , Olho/ultraestrutura , Retina/anatomia & histologia , Retina/citologia , Retina/ultraestrutura , Modelos Biológicos , Fenômenos Fisiológicos OcularesRESUMO
We are describing a rhabdom organization of the eye of the chrysanthemum beetle Phytoecia rufiventris that to date has not been described from any other insect. In cerambycid beetles free rhabdomeres, forming a circular, open rhabdom, surround a central rhabdom made up of the rhabdomeres of one or two cells. In Phytoecia rufiventris the central rhabdomeres are missing throughout the eye and the microvilli of the outer 6 rhabdomeres are regularly oriented in three directions. Following the classification of rhabdom types suggested by Wachmann (1979), we suggest to name the rhabdom arrangement seen in the retina of Phytoecia rufiventris [quot ]Grundmuster 3[quot ]. This pattern ought to facilitate polarization sensitivity and movement perception, features that agree with the behavioural repertoire of Phytoecia rufiventris.(AU)
Assuntos
Animais , Membrana Basal/citologia , Membrana Basal , Olho/anatomia & histologia , Olho/citologia , Olho/ultraestrutura , Retina/anatomia & histologia , Retina/citologia , Retina/ultraestrutura , Besouros/anatomia & histologia , Besouros/fisiologia , Modelos Biológicos , Fenômenos Fisiológicos OcularesRESUMO
BACKGROUND: Platelet-rich plasma is a blood-derived fraction that contains a high concentration of platelets and growth factors. It was proposed that the use of this platelet concentrate stimulates tissue repair. However, little is known about the biologic response of gingival fibroblasts to platelet's derived growth factors. In the present study, we evaluated whether platelet-rich plasma modulated cell adhesion, cell migration, and myofibroblastic differentiation in primary cultures of human gingival fibroblasts. METHODS: We studied the response of primary cultures of gingival fibroblasts to thrombin-activated platelet-rich plasma fractions. Cell adhesion was evaluated through a colorimetric assay. Cell spreading, actin cytoskeleton remodeling, and focal adhesion distribution were assessed through light and immunofluorescence microscopy. Cell migration was analyzed using a bicameral cell culture system. Smooth muscle actin production was studied through Western blotting. RESULTS: Exposure of gingival fibroblasts to platelet-rich plasma stimulated adhesion and spreading of cells on fibronectin matrices, the development of actin-enriched cellular extensions, and formation of focal adhesions. Platelet-rich plasma also promoted cell migration and invasion through a reconstituted basement membrane matrix. Differentiation into the myofibroblastic phenotype, assessed through the production of smooth muscle actin, was also stimulated by platelet-rich plasma preparations. CONCLUSION: Platelet-rich plasma may modulate several cell responses potentially involved in wound healing such as cell adhesion, cell migration, and myofibroblastic differentiation.
Assuntos
Fibroblastos/fisiologia , Gengiva/citologia , Plasma Rico em Plaquetas , Actinas/análise , Adulto , Membrana Basal/citologia , Adesão Celular/fisiologia , Diferenciação Celular/fisiologia , Movimento Celular/fisiologia , Células Cultivadas , Proteínas do Citoesqueleto/análise , Feminino , Fibroblastos/citologia , Fibronectinas/química , Adesões Focais/fisiologia , Humanos , Masculino , Plasma Rico em Plaquetas/fisiologiaRESUMO
Early ovarian regression was analyzed in the neotropical freshwater teleost, curimatã-pacu (Prochilodus argenteus), in order to evaluate follicular apoptosis, basement membrane morphology, and integrin beta1 and collagen type IV immunostainning in postovulatory follicles. Mature females were induced to spawn by using carp pituitary extract for study of ovarian regression up to 5 days post-spawning. Morphometric analyses showed that the postovulatory follicle area decreased progressively after spawning and was coupled to the gonadosomatic index (r=0.92). During ovarian regression, follicular cells detached from the neighboring cells and basement membrane and then died by apoptosis. The follicular basement membrane became thicker and diffuse and was breached during regression of the postovulatory follicles. Follicular apoptosis was detected by TUNEL, histology, and electron microscopy. The ladder pattern of apoptotic DNA was revealed by agarose gel electrophoresis. The apoptotic index for the follicular cells increased until 3 days post-spawning and decreased thereafter. Immunohistochemistry reactions detected caspase 3, integrin beta1, and collagen type IV in the follicular layer of the postovulatory follicles. Labeling for integrin beta1 and collagen type IV decreased significantly, whereas a peak in cell death occurred 3 days post-spawning. At 4-5 days post-spawning, the connective theca was more thickened and vascularized. Simultaneously, granulocytes migrated toward the follicular lumen. Thus, follicular apoptosis contributes to early ovarian regression in P. argenteus. Additionally, our findings suggest integrin beta1 and collagen type IV as possible survival factors for follicular cells in teleost ovary.
Assuntos
Apoptose/fisiologia , Colágeno Tipo IV/metabolismo , Integrina beta1/metabolismo , Folículo Ovariano/fisiologia , Ovulação/fisiologia , Animais , Membrana Basal/citologia , Membrana Basal/ultraestrutura , Caspase 3/metabolismo , Fragmentação do DNA , Feminino , Peixes , Marcação In Situ das Extremidades Cortadas , Tamanho do Órgão , Folículo Ovariano/citologia , Folículo Ovariano/ultraestrutura , Ovário/citologia , Ovário/ultraestrutura , Células Tecais/citologia , Células Tecais/metabolismoRESUMO
The authors quantified the type IV collagen fibers volumetric density in the basement membrane of bladder wall of ovariectomized rats with and without estradiol replacement. This study was conducted on 40 Wistar rats (3 months old) randomly divided in 4 groups: group 1, remained intact (control); group 2, submitted to bilateral oophorectomy and daily replacement 4 weeks later of 17 beta-estradiol for 12 weeks; group 3, sham operated and daily replacement 4 weeks later of sesame oil for 12 weeks; and group 4, submitted to bilateral oophorectomy and killed after 12 weeks. It was used in immunohistochemistry evaluation using type IV collagen polyclonal antibody to stain the fibers on paraffin rat bladder sections. The M-42 stereological grid system was used to analyze the fibers. Ovariectomy had an increase effect on the volumetric density of the type IV collagen fibers in the basement membrane of rat bladder wall. Estradiol replacement in castrated animals demonstrated a significative difference in the stereological parameters when compared to the castrated group without hormonal replacement. Surgical castration performed on rats induced an increasing volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall and the estradiol treatment had a significant effect in keeping a low volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall.
Assuntos
Colágeno Tipo IV/metabolismo , Estradiol/fisiologia , Bexiga Urinária/citologia , Animais , Membrana Basal/citologia , Feminino , Imuno-Histoquímica , Ovariectomia , Ratos , Ratos WistarRESUMO
OBJECTIVE: We investigated factors that may be involved in the reduced leukocyte migration observed in intrauterine undernourished rats. METHODS: Male Wistar rat offspring (8-9 wk of age) of dams fed during pregnancy with 50% less food than control dams were used to measure L-selectin expression (by flow cytometry), bone marrow cell count, blood cell count, laminin and type IV collagen in the basal membrane of venules of the spermatic fascia (by immunohistochemistry), total protein level and serum albumin, and the production of leukotriene B4 after stimulation with tumor necrosis factor-alpha and corticosterone plasma levels (by enzyme-linked immunosorbent assay). RESULTS: Hypocellularity in bone marrow and peripheral blood and reduced L-selectin expression were found in the undernourished rat offspring (UR) compared with nourished offspring (NR; P < 0.05). Type IV collagen in the basal membrane of the venules of the spermatic fascia was less in UR than in NR (P < 0.05). The total protein levels and serum albumin did not differ between the two groups. Leukotriene B4 production after stimulation with tumor necrosis factor-alpha was lower in UR (P < 0.05). These differences could not be attributed to circulating glucocorticoids levels, which were not different in the NR and UR groups. CONCLUSION: Our data suggest that all observed differences contribute to reduced leukocyte migration in undernourishment.
Assuntos
Membrana Basal , Movimento Celular/fisiologia , Doenças Fetais/fisiopatologia , Inflamação/imunologia , Leucócitos/fisiologia , Desnutrição/fisiopatologia , Fenômenos Fisiológicos da Nutrição Pré-Natal , Animais , Membrana Basal/citologia , Membrana Basal/imunologia , Células da Medula Óssea/fisiologia , Colágeno Tipo IV/fisiologia , Corticosterona/sangue , Feminino , Doenças Fetais/imunologia , Doenças Fetais/metabolismo , Citometria de Fluxo , Imuno-Histoquímica , Selectina L/metabolismo , Laminina/metabolismo , Leucócitos/imunologia , Leucotrieno B4 , Masculino , Desnutrição/imunologia , Desnutrição/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Distribuição Aleatória , Ratos , Ratos Wistar , Albumina Sérica/análiseRESUMO
BACKGROUND AND OBJECTIVES: Epithelial rests of Malassez are clusters of cells derived from Hertwig's root sheath that remain in the periodontal ligament throughout life. Although it is known that the cells of Malassez proliferate, there are no studies showing that they undergo programmed cell death, i.e. apoptosis. In most tissues, proliferation is balanced by apoptosis. Thus we examined regions of the periodontium of young and adult rat molars in the hope of detecting apoptosis. METHODS: Wistar rats aged 29, 45 and 120 days were killed with chloral hydrate (600 mg/kg). Fragments containing maxillary molars were removed and fixed in formaldehyde, decalcified, and embedded in paraffin and glycol methacrylate. Sections were stained with hematoxylin/eosin and the Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL) method for detection of apoptosis. Specimens were also fixed in glutaraldehyde-formaldehyde, decalcified and processed for transmission electron microscopy. RESULTS: Epithelial rests of Malassez containing round/ovoid basophilic dense bodies and TUNEL-positive structures were found in all specimens examined. Ultrastructural examination revealed that some cells of Malassez contained masses of condensed peripheral chromatin and a shrunken cytoplasm exhibiting intact organelles--images typical of apoptosis. Moreover, round/ovoid electron-opaque structures appeared to be in the process of being engulfed by neighboring epithelial cells of Malassez. CONCLUSIONS: Our results demonstrate that epithelial cells of Malassez's rests undergo apoptosis in the developing and adult periodontium. Apoptosis may, together with proliferation, be part of the mechanism of turnover/remodelling of the cells of Malassez.
Assuntos
Apoptose , Ligamento Periodontal/citologia , Animais , Membrana Basal/citologia , Núcleo Celular/ultraestrutura , Proliferação de Células , Cromatina/ultraestrutura , Corantes , Citoplasma/ultraestrutura , Células Epiteliais/citologia , Técnicas de Preparação Histocitológica , Marcação In Situ das Extremidades Cortadas , Corpos de Inclusão/ultraestrutura , Microscopia Eletrônica de Transmissão , Organelas/ultraestrutura , Ratos , Ratos WistarRESUMO
Collagen-tailed asymmetric acetylcholinesterase (AChE) forms are believed to be anchored to the synaptic basal lamina via electrostatic interactions involving proteoglycans. However, it was recently found that in avian and rat muscles, high ionic strength or polyanionic buffers could not detach AChE from cell-surface clusters and that these buffers solubilized intracellular non-junctional asymmetric AChE rather than synaptic forms of the enzyme. In the present study, asymmetric AChE forms were specifically solubilized by ionic buffers from synaptic basal lamina-enriched fractions, largely devoid of intracellular material, obtained from the electric organ of Torpedo californica and the end plate regions of rat diaphragm muscle. Furthermore, foci of AChE activity were seen to diminish in size, number, and staining intensity when the rat synaptic basal lamina-enriched preparations were treated with the extraction buffers. In the case of Torpedo, almost all the AChE activity was removed from the pure basal lamina sheets. We therefore conclude that a major portion of extracellular collagen-tailed AChE is extractable from rat and Torpedo synaptic basal lamina by high ionic strength and heparin buffers, although some non-extractable AChE activity remains associated with the junctional regions.
Assuntos
Acetilcolinesterase/metabolismo , Membrana Basal/enzimologia , Heparina/farmacologia , Sais/farmacologia , Acetilcolinesterase/classificação , Animais , Membrana Basal/citologia , Membrana Basal/ultraestrutura , Centrifugação com Gradiente de Concentração , Diafragma/enzimologia , Órgão Elétrico/enzimologia , Histocitoquímica , Microscopia Eletrônica , Placa Motora/citologia , Placa Motora/enzimologia , Concentração Osmolar , Ratos , Solubilidade , Sinapses/enzimologia , TorpedoRESUMO
Resumo: A excreçäo urinária de componentes da mebrana basal, específicamente colágeno IV e laminina, foi determinada através de "immunoblotting", e estudada em ratos Wistar machos, diabéticos-induzido por drogas (aloxana e estreptozotacina)EV, e comparada a controles, em funçäo do tempo de doença. Estudamos, também, as funçöes renais: gloerular e tubular, avalinado, respectivamente, clearance de creatina e de lítio. Além disso, aspectos morfológicos renais foram analizados utilizando-se técnicas de PAS e de imuno-histoquímica, para colágeno IV e laminina, com o objetivo de verificar possíveis alteraçöes da membrana basal. Assim pudemos obeservar excreçöes de fraçöes urinárias de colágeno IV (88 e 75 kDa) e laminina (108 a 88 kDa), em ambos os modelos de DM, em todos os tempos estudados . Entretanto, a fraçäo de 57 kDa da laminina, nos animais diabéticos-induzido por estreptozotocina, somente foi expressa a partir da quinta semana da doença, enquanto nos diabéticos-induzidopor aloxana sua excreçäo foi verificada precocedente (segundo dia). As alteraçöes da funçäo renal foram semelhantes nos dois modelos, porém de maneira mais intensa no modelo aloxânico. Dentre elas destacaram-se: diminuiçäo progressiva da taxa de filtraçäo glomerular, aumento da fraçäo de escreçäo de sódio;e, dimuiçäo da reabsorçäo deste íon, näo compensada por aumento da reabsorçäo distal.