RESUMO
OBJECTIVE: To study the combined and isolated effects of melatonin and metformin in the ovarian tissue of rats with PCOS. DESIGN: Experimental study using a rat model of PCOS induced by continuous light exposure. INTERVENTION(S): Forty adult female rats were divided into 5 groups: physiological estrus phase (Sham); permanente estrus with PCOS induced by continuous lighting exposure for 60 consecutive days (control); with PCOS treated with melatonin; with PCOS treated with metformin; with PCOS treated with melatonin + metformin. After 60 days of treatments, all rats were killed, and ovaries were collected and processed for paraffin-embedding. Formalin-fixed paraffin-embedded sections were stained with hematoxylin and eosin or subjected to immunohistochemistry for proliferation (Ki-67) and apoptosis (cleaved caspase 3) detection markers. SETTING: Federal University of São Paulo, Brazil. ANIMALS: Forty adult female Wistar rats (Rattus norvegicus albinus). MAIN OUTCOME MEASURE(S): Number of corpus luteum and ovarian cysts, number of ovarian follicles (primary and antral follicles), number of interstitial cells, percentage of ovarian follicles (primary and antral follicles), and of interstitial cells immunostained to cleaved caspase-3 and Ki-67. RESULTS: Absence of corpus luteum, a higher number of cysts, and increased nuclear volume and area of interstitial cells, along with a decrease in primary and antral follicle numbers, were noticed in the control group compared with the Sham group. Melatonin and metformin treatments attenuated these effects, although the combined treatment did not mitigate the increased number of cysts and ovaries induced by PCOS. An increase in theca interna cell apoptosis was observed in the control group, whereas melatonina and metformin treatments reduced it significantly. A higher percentage of caspase-3-immunostained granulosa cells was noted in the Sham and all treated groups compared with the control group; no aditive effects on ovarian cell apoptosis were observed in the combined treatment. The percentage of Ki-67- immunostained granulosa cells was significantly higher in the control group compared with the Sham group. However, the combined treatment, not melatonin and metformin alone, mitigated this effect. A higher percentage of Ki-67-immunostained interstitial cells was observed in all treated groups compared with the Sham and control groups, whereas no additive effects in that immunoreactivity were observed in the combined treatment. CONCLUSIONS: Melatonin and metformin may improve ovarian function in rats with PCOS. The combined melatonin and metformin treatment is more effective in attenuating excessive granulosa cell proliferation, but it is not more effective in improving ovarian function than these drugs applied alone in rats with PCOS.
Assuntos
Melatonina , Metformina , Ovário , Síndrome do Ovário Policístico , Ratos Wistar , Animais , Feminino , Metformina/farmacologia , Metformina/administração & dosagem , Síndrome do Ovário Policístico/tratamento farmacológico , Síndrome do Ovário Policístico/patologia , Síndrome do Ovário Policístico/induzido quimicamente , Melatonina/farmacologia , Melatonina/administração & dosagem , Ovário/efeitos dos fármacos , Ovário/patologia , Ratos , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Modelos Animais de Doenças , Antígeno Ki-67/metabolismo , Antígeno Ki-67/análiseRESUMO
BACKGROUND: Annexin A1 (ANXA1) and the NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome play important roles in bone remodeling. However, expression profiles of these factors in bone cells under diabetes mellitus (DM) and estrogen-deficient conditions are poorly understood. This study investigated the immunoexpression of ANXA1 and its formyl peptide receptor 2 (FPR2), as well as NLRP3 inflammasome mediators, during remodeling of the alveolar process in diabetic and estrogen-deficient rats. METHODS: Twenty adult female Wistar rats were divided into four groups (n = 5): Sham-operated (SHAM) and ovariectomized (OVX) rats received a vehicle solution, and SHAM and OVX rats were intraperitoneally administered 60 mg/kg/body weight (BW) of streptozotocin (STZ) to induce DM (SHAM-Di and OVX-Di groups). After 7 weeks, the rats were euthanized and their maxillae were fixed in phosphate-buffered 4% formaldehyde and embedded in paraffin. Sections were stained with hematoxylin/eosin (H&E) and picrosirius red or subjected to immunohistochemical detection of ANXA1, FPR2, NLRP3, interleukin-1ß (IL-1ß), and cyclooxygenase-2 (COX2). RESULTS: Estrogen deficiency and DM were associated with deleterious effects in bone tissue, as evidenced by a lower number of osteocytes and higher number of empty lacunae in the SHAM-Di and OVX-Di groups compared to the nondiabetic groups. Both diabetic groups showed a smaller vascular area and weaker collagen fiber birefringence intensity in alveolar bone tissue. A significantly higher number of ANXA1/FPR2-positive osteoblasts, osteocytes, and osteoclasts was accompanied by a significantly higher number of these cells immunolabeled for COX2, NLRP3, and IL-1ß in the diabetic and OVX groups, especially in both estrogen-deficient and diabetic rats. CONCLUSION: These results indicate a possible role for the ANXA1/FPR2 pathway as a fine-tuning/anti-inflammatory regulator to counterbalance exacerbated COX2/NLRP3/IL-1ß activation in bone cells during bone remodeling under estrogen deficiency and DM.
RESUMO
It is known that estrogen deficiency increases osteoclast formation and activity. Autophagy, a cell survival pathway, has been shown to be crucial for osteoclast function. However, little is known about the effects of estrogen depletion on osteoclast autophagy. Here, we evaluated the effects of estrogen deficiency in the immunoexpression of autophagy mediators in alveolar bone osteoclasts of ovariectomized rats. Twelve adult female rats were ovariectomized (OVX-group) or SHAM-operated (SHAM-group). After three weeks, the rats were euthanized and maxillary fragments containing alveolar bone of the first molars were processed for light microscopy or transmission electron microscopy (TEM). Paraffin-sections were subjected to the TRAP method (osteoclast marker) or to the immunohistochemical detections of beclin-1, LC3α, and p62 (autophagy mediators); araldite-sections were processed for TEM. The number of TRAP-positive osteoclasts and the number of immunolabeled-multinucleated cells (MNCs) along the alveolar bone surface of the first molar were computed. The number of TRAP-positive osteoclasts and the number of beclin-1-, LC3α- and p62-immunolabelled osteoclasts were significantly higher in OVX-group than the SHAM-group. MNCs were frequently located juxtaposed to Howship lacunae along the alveolar bone surface, indicating that these cells are osteoclasts. TEM revealed osteoclasts exhibiting autophagosomes. Our data indicate that autophagy plays an important role during estrogen deficiency-induced osteoclastogenesis. Thus, our results contribute to a better understanding on the role of autophagy on osteoclasts under estrogenic deficiency, and reinforce the idea that modulation of autophagy may be a useful tool to inhibit excessive oral bone resorption in post-menopausal women.
Assuntos
Autofagia/fisiologia , Estrogênios/metabolismo , Osteoclastos/citologia , Osteoclastos/metabolismo , Animais , Reabsorção Óssea/metabolismo , Feminino , Microscopia Eletrônica de Transmissão , Ratos , Ratos WistarRESUMO
AIM: Although soy isoflavones (ISO) have been shown to relief postmenopausal symptoms, it remains inconclusive whether ISO can improve lipid-profile without uterotrophic effects under estrogen-deficiency. Thus, we investigated the effects of ISO on lipid-profile and uterus of ovariectomized (Ovx) rats. MATERIALS AND METHODS: Twenty-five adult rats were Ovx or Sham-operated (Sham) and assigned into five groups: Sham and Ovx groups, administered with vehicle solutions; Ovx-E, treated with 10 µg/kg of 17ß-Estradiol; Ovx-ISO, treated with 200 mg/kg of ISO; Ovx-E + ISO, treated with estradiol + ISO combined. After fifty days of treatments, rats were euthanized and uterine horns were processed for histomorphometry or to collagen fibers and glycosaminoglycans evaluations. Blood samples were collected to evaluate levels of triglycerides, total cholesterol (TC) and its fractions (HDL/VLDL). Data were subjected to statistical analysis (p < .05). RESULTS: Uterus weight was lower in Ovx group than the Sham and Ovx-E groups, whereas it was similar between Ovx and Ovx-ISO groups. Histomorphometry showed atrophic uterus in Ovx and Ovx-ISO groups, whereas uterotrophic effects were noticed in Ovx-E and Ovx-E + ISO groups. Collagen fibers-birefringence was higher in Sham, Ovx, and Ovx-ISO groups than in Ovx-E and Ovx-E + ISO groups. Sulfated glycosaminoglycans content was similar among Sham, Ovx, and Ovx-ISO groups, while it was higher in estrogen-treated groups; total glycosaminoglycans content was similar among groups. TC and HDL was higher in Ovx-ISO group, whereas VLDL and triglycerides levels was higher in Ovx-E + ISO group and similar among other groups. CONCLUSION: Soy isoflavones at 200 mg/kg have slight beneficial effects on lipid-profile without uterotrophic effects in Ovx rats.
Assuntos
Glycine max , Isoflavonas/uso terapêutico , Metabolismo dos Lipídeos/efeitos dos fármacos , Fitoterapia , Útero/efeitos dos fármacos , Animais , Avaliação Pré-Clínica de Medicamentos , Feminino , Colágenos Fibrilares/metabolismo , Glicosaminoglicanos/metabolismo , Isoflavonas/farmacologia , Ovariectomia , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Ratos Wistar , Útero/metabolismoRESUMO
OBJECTIVE: To evaluate the histomorphometric and immunohistochemical changes in interstitial cells and ovarian follicles of rats treated with clomiphene citrate during and after induction of permanent estrus. METHODS: Twenty four adult-female rats with regular estrous cycle were equally divided into three groups: (1) GCtrl-at estrous phase. (2) GPCOS-at permanent-estrous phase. (3) GCC-PCOS rats, which remained exposed to 60 days of continuous illumination and treated with Clomiphene Citrate. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 detections. RESULTS: The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in GCC, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells, as well as a decrease in nuclear volume of interstitial cells. The percentage of cell proliferation was significantly higher in granulosa cells of the GCC. On the other hand, the percentage of apoptosis was significantly higher in the granulosa cells of GPCOS than the GCC. CONCLUSION: The ovaries of rats treated with clomiphene citrate showed a decrease in the number of cysts, an increase in the number of ovarian follicles, the presence of corpus luteum along with a decrease in the nuclear volume in the area occupied by interstitial cells.
Assuntos
Clomifeno/farmacologia , Folículo Ovariano/efeitos dos fármacos , Síndrome do Ovário Policístico , Células Tecais/efeitos dos fármacos , Animais , Caspase 3/metabolismo , Clomifeno/uso terapêutico , Modelos Animais de Doenças , Estro/efeitos dos fármacos , Estro/metabolismo , Feminino , Técnicas Histológicas , Imuno-Histoquímica , Antígeno Ki-67/metabolismo , Folículo Ovariano/metabolismo , Folículo Ovariano/patologia , Ovário/efeitos dos fármacos , Ovário/metabolismo , Ovário/patologia , Síndrome do Ovário Policístico/tratamento farmacológico , Síndrome do Ovário Policístico/metabolismo , Síndrome do Ovário Policístico/patologia , Ratos , Ratos Wistar , Células Tecais/metabolismo , Células Tecais/patologiaRESUMO
Although both estrogen deficiency and diabetes contribute to periodontal tissue deterioration, the combined effects of these conditions on periodontium is unknown. Thus, we analyzed the combined effects of ovariectomy followed by streptozotocin (STZ)-induced diabetes on periodontal tissues of rats. Twenty adult rats were ovariectomized (OVX) or SHAM-operated (SHAM). After 3 weeks, the rats received an intraperitoneal injection of STZ (60 mg/kg/body weight) to induce diabetes or vehicle (blank) solution. The groups were assigned as follows (n = 5): SHAM-vehicle (SHAM), OVX-vehicle (OVX), SHAM + STZ (SHAM-Di), and OVX + STZ (OVX-Di). Seven weeks post-diabetes induction, the rats were euthanized. Blood samples were collected for glucose measurements and maxillae were processed for paraffin embedding. Sections stained with hematoxylin/eosin, Masson's trichrome, and picrosirius-red were used for alveolar bone loss and collagen fiber analysis in the lamina propria. Immunohistochemistry was performed for runt-related transcription factor 2 (Runx2), matrix metalloproteinase 9 (MMP-9), and tryptase detection. Alveolar bone loss and fewer collagen fibers were observed in the OVX-Di group, collagen fibers with irregular organization, and MMP-9 immunoreactivity were more evident in diabetic groups, and MMP-9-positive osteoclasts on alveolar bone surface were noticed in all groups. The OVX-Di group showed lower Runx2 immunoreactivity (osteoblast formation marker), and more tryptase-positive cells (mast cell marker) in the alveolar bone marrow. Our results indicate that estrogen depletion, followed by STZ-induced diabetes, promotes periodontal tissue deterioration that is more evident than both interventions applied alone. Furthermore, our results points to a possible participation of bone-derived mast cells in this process.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Estrogênios/deficiência , Periodonto/metabolismo , Estreptozocina/farmacologia , Perda do Osso Alveolar/metabolismo , Animais , Densidade Óssea/fisiologia , Feminino , Mastócitos/metabolismo , Osteoclastos/metabolismo , Osteócitos/metabolismo , Ovariectomia/métodos , Ligamento Periodontal/metabolismo , Ratos , Ratos WistarRESUMO
OBJECTIVE: Although estrogen therapy is widely used against post-menopausal symptoms, it can present adverse effects, including endometrial cancer. Soy isoflavones are considered a possible alternative to estrogen therapy. However, there are still concerns whether isoflavones exert trophic effects on the uterine cervix. To evaluate the histomorphometric and immunohistochemical alterations in the uterine cervix of ovariectomized rats treated with soy isoflavones (Iso). METHODS: Fifteen adult Wistar rats were ovariectomized (Ovx) and divided into three groups: Group I (Ovx), administered with vehicle solution; Group II (OVX-Iso), administered with concentrated extract of Iso (150 mg/kg) by gavage; and Group III (OVX-E2), treated with 17ß-estradiol (10 µg/kg), subcutaneously. After 30 days of treatments, the uterine cervix was fixed in 10% formaldehyde and processed for paraffin-embedding. Sections were stained with Hematoxylin and eosin for morphological and morphometric studies or subjected to immunohistochemistry for detections of Ki-67 and vascular endothelial growth factor-A (Vegf-A). The data obtained were subjected to statistical analysis (p ≤ 0.05). RESULTS: We noted an atrophic uterine cervix in GI, whereas it was more voluminous in GII and even more voluminous in GIII. The thickness of the cervical mucosa was significantly higher in GIII, as compared to GI and GII. The cell proliferation (Ki-67) was significantly elevated in the estradiol and isoflavones treated groups, whereas Vegf-A immunoexpression was significantly higher in GIII, as compared to groups GII and GI. CONCLUSIONS: Soy isoflavones cause less trophic and proliferative effects in the uterine cervix of rats as compared to estrogen.
Assuntos
Colo do Útero/efeitos dos fármacos , Estrogênios/farmacologia , Isoflavonas/farmacologia , Fitoestrógenos/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Colo do Útero/patologia , Epitélio/efeitos dos fármacos , Feminino , Imuno-Histoquímica , Antígeno Ki-67/análise , Mucosa/efeitos dos fármacos , Ovariectomia , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular/análiseRESUMO
SUMMARY INTRODUCTION Although estrogen therapy is widely used against post-menopausal symptoms, it can present adverse effects, including endometrial cancer. Soy isoflavones are considered a possible alternative to estrogen therapy. However, there are still concerns whether isoflavones exert trophic effects on the uterine cervix. OBJECTIVES To evaluate the histomorphometric and immunohistochemical alterations in the uterine cervix of ovariectomized rats treated with soy isoflavones (Iso). METHODS Fifteen adult Wistar rats were ovariectomized (Ovx) and divided into three groups: Group I (Ovx), administered with vehicle solution; Group II (OVX-Iso), administered with concentrated extract of Iso (150 mg/kg) by gavage; and Group III (OVX-E2), treated with 17β-estradiol (10 µg/kg), subcutaneously. After 30 days of treatments, the uterine cervix was fixed in 10% formaldehyde and processed for paraffin-embedding. Sections were stained with Hematoxylin and eosin for morphological and morphometric studies or subjected to immunohistochemistry for detections of Ki-67 and vascular endothelial growth factor-A (Vegf-A). The data obtained were subjected to statistical analysis (p ≤ 0.05). RESULTS We noted an atrophic uterine cervix in GI, whereas it was more voluminous in GII and even more voluminous in GIII. The thickness of the cervical mucosa was significantly higher in GIII, as compared to GI and GII. The cell proliferation (Ki-67) was significantly elevated in the estradiol and isoflavones treated groups, whereas Vegf-A immunoexpression was significantly higher in GIII, as compared to groups GII and GI. CONCLUSIONS Soy isoflavones cause less trophic and proliferative effects in the uterine cervix of rats as compared to estrogen.
RESUMO INTRODUÇÃO Embora a terapia estrogênica seja amplamente utilizada contra sintomas pós-menopausais, ela pode apresentar efeitos adversos, incluindo câncer de mama e endometrial. Assim, as isoflavonas da soja são consideradas uma alternativa possível à terapia estrogênica. No entanto, ainda há controvérsias se estes compostos exercem efeitos tróficos significativos no colo do útero. OBJETIVOS Avaliar as alterações histomorfométricas e imuno-histoquímicas no colo do útero de ratas ovariectomizadas tratadas com isoflavonas da soja (iso). MÉTODOS Quinze ratas Wistar adultas foram ovariectomizadas bilateralmente (Ovx) e separadas em três grupos: Grupo I (Ovx) - veículo (propilenoglicol); Grupo II (Ovx-Iso) - receberam extrato concentrado de Iso (150 mg/kg) e Grupo III (Ovx-E2) - tratado com 17β-estradiol (10 µg/kg); as soluções foram administradas via gavagem por 30 dias consecutivos. Posteriormente, os colos uterinos foram retirados, fixados em formaldeído a 10% tamponado e processados para inclusão em parafina. Cortes (4 µm) foram coradas com hematoxilina e eosina para estudo morfológico e morfométricos, enquanto outros foram submetidos à imuno-histoquímica para detecção de Ki-67 e do fator de crescimento endotelial vascular-A (Vegf-A). Os dados obtidos foram submetidos à análise estatística (p≤0,05). RESULTADOS Observamos a presença de colo uterino atrófico no GI (Ovx), sendo este mais volumoso no GII (Ovx+Iso) e ainda mais volumoso no GIII (Ovx+E2). A espessura da mucosa cervical foi significativamente maior no GIII (Ovx-E2), em comparação ao GI (Ovx) e ao GII (Ovx-Iso). A proliferação celular (Ki-67) foi significativamente mais elevada nos grupos tratados com estradiol e isoflavonas, enquanto a imunoexpressão de Vegf-A foi significativamente maior no GIII (Ovx-E2), em comparação ao GII (Ovx-Iso) e ao GI (Ovx-E2). CONCLUSÕES As isoflavonas da soja causam menos efeitos tróficos e proliferativos no colo do útero de ratas em comparação ao estrogênio.
Assuntos
Humanos , Animais , Colo do Útero/efeitos dos fármacos , Fitoestrógenos/farmacologia , Estrogênios/farmacologia , Isoflavonas/farmacologia , Fatores de Tempo , Imuno-Histoquímica , Ovariectomia , Distribuição Aleatória , Colo do Útero/patologia , Reprodutibilidade dos Testes , Ratos Wistar , Antígeno Ki-67/análise , Fator A de Crescimento do Endotélio Vascular/análise , Proliferação de Células/efeitos dos fármacos , Epitélio/efeitos dos fármacos , Mucosa/efeitos dos fármacosRESUMO
OBJECTIVE: To evaluate the ovarian effects of melatonin (Mel) in a rat model of polycystic-ovary-syndrome (PCOS) before and after permanent estrus induction. METHODS: Thirty-two adult-female rats with regular estrous cycle were equally divided into four groups: 1) GCtrl - at estrous phase. 2) GPCOS - at permanent-estrous phase. 3) GMel1 - treated for 60 days with Mel (0.4 mg/Kg) during permanent estrus induction and 4) GMel2 - rats with PCOS and treated for 60 days with Mel. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 (Casp-3) detections. RESULTS: The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in Mel-treated groups, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells. These results were more evident in GMel1. The percentage of Ki-67-positive cells was significantly higher in the Mel-treated groups, mainly in the GMel2, as compared to GPCOS. On the other hand, the percentage of Casp-3-positive cells was significantly lower in granulosa cells of GMel1, whereas it was significantly higher in the interstitial-like cells of GMel2, in comparison to GPCOS. CONCLUSION: Melatonin administration prevents the permanent estrus state in the PCOS rat model. This effect is more efficient when melatonin is administered before permanent estrus induction.
Assuntos
Melatonina/uso terapêutico , Síndrome do Ovário Policístico/prevenção & controle , Animais , Estro/fisiologia , Feminino , Imuno-Histoquímica , Síndrome do Ovário Policístico/patologia , Estudos Prospectivos , Distribuição Aleatória , Reprodutibilidade dos Testes , Células Tecais/patologia , Resultado do TratamentoRESUMO
SUMMARY OBJECTIVE To evaluate the ovarian effects of melatonin (Mel) in a rat model of polycystic-ovary-syndrome (PCOS) before and after permanent estrus induction. METHODS Thirty-two adult-female rats with regular estrous cycle were equally divided into four groups: 1) GCtrl - at estrous phase. 2) GPCOS - at permanent-estrous phase. 3) GMel1 - treated for 60 days with Mel (0.4 mg/Kg) during permanent estrus induction and 4) GMel2 - rats with PCOS and treated for 60 days with Mel. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 (Casp-3) detections. RESULTS The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in Mel-treated groups, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells. These results were more evident in GMel1. The percentage of Ki-67-positive cells was significantly higher in the Mel-treated groups, mainly in the GMel2, as compared to GPCOS. On the other hand, the percentage of Casp-3-positive cells was significantly lower in granulosa cells of GMel1, whereas it was significantly higher in the interstitial-like cells of GMel2, in comparison to GPCOS. CONCLUSION Melatonin administration prevents the permanent estrus state in the PCOS rat model. This effect is more efficient when melatonin is administered before permanent estrus induction.
RESUMO OBJETIVO Avaliar os efeitos ovarianos da melatonina (Mel) em ratas com síndrome dos ovários policísticos (SOP) antes e após a indução do estro-permanente. MÉTODOS Trinta e duas ratas com ciclos estrais regulares foram igualmente divididas em quatro grupos: 1) GCtrl - fase de estro. 2) GSOP - fase de estro-permanente. 3) GMel1 - tratadas por 60 dias com Mel (0,4 mg/kg) durante a indução do estro-permanente e 4) GMel2 - ratas com SOP e tratadas com Mel. Após eutanásia dos animais, os ovários foram processados para inclusão em parafina. Cortes foram corados com H.E ou submetidos à imuno-histoquímica para detecção de Ki-67 e caspase-3 clivada (Casp-3). RESULTADOS O GSOP mostrou ausência de corpos lúteos e vários cistos ovarianos, além de inúmeras células intersticiais. A presença de corpos lúteos e o aumento significativo dos folículos primários e antrais foram observados nos grupos tratados com Mel, os quais também mostraram diminuição no número de cistos ovarianos e na área ocupada pelas células intersticiais. Esses resultados foram mais evidentes no GMel1 do que no GMel2. A porcentagem de células Ki-67 positivas foi significativamente maior no GMel1 e no GMel2, sendo mais evidente no GMel2, em comparação ao GSOP. Por outro lado, a porcentagem de células positivas à Casp-3 foi menor nas células da granulosa do GMel1 e maior nas células intersticiais do GMel2, em comparação ao GSOP. CONCLUSÃO A administração de melatonina previne o estado de estro-permanente em ratas com SOP. Esse efeito é mais eficiente quando a melatonina é administrada após indução do estado de estro-permanente.