Proliferation of the superficial epithelium of ovaries in senile female rats following oral administration of conjugated equine estrogens

OBJECTIVE: To evaluate the effect of different concentrations of estrogen on the ovarian superficial epithelium in senile female rats. Design: Fifty female rats at 15 months of age and with irregular estrous cycles were selected and randomly divided into five experimental groups containing equal numbers of animals in each: GPROP, control group receiving vehicle only; GE0.05mg, group receiving conjugated equine estrogens (CEE) at a dose of 50 µg/kg; GE0.5mg, group receiving CEE at 500 µg/kg; GE1mg, group receiving CEE at 1 mg/kg; and GE2mg, receiving CEE at 2 mg/kg. The length of treatment was 21 days. After this period, the animals were anesthetized and the ovaries were fixed in 10% formaldehyde and processed for routine histology. Histomorphology was analyzed by light microscopy, and histomorphometrics were evaluated using the Imagelab program. RESULTS: In the GPROP and GE0.05mg groups, the superficial epithelium of the ovary had a simple cuboidal shape, and as the estrogen dose increased, the epithelium thickened, with pseudo-stratified or stratified epithelium appearing in the GE2mg group. The animals in the group given the highest estrogen dose (GE2mg) showed the thickest ovarian epithelium and the largest perimeter and surface area of the surface ovarian epithelium (P < 0.01). However, the difference in epithelium thickness between the GE0.5mg and GE1mg groups was only slight. CONCLUSION: Our data suggest that CEE at a dose of 2 mg/kg may induce marked proliferation of rat ovarian epithelium.UNIFESP Morphology Department Histology and Cellular Biology DivisionUniversidade de São Paulo Faculdade de MedicinaUniversidade Federal de São Paulo (UNIFESP) Faculdade de Medicina Gynecology DepartmentUNIFESP, Morphology Department Histology and Cellular Biology DivisionUNIFESP, Faculdade de Medicina Gynecology DepartmentSciEL

Proliferation of the ovarian superficial epithelium after administration of conjugated equine estrogens in senile female rats

OBJECTIVE: To evaluate the effect of different concentrations of estrogen on the ovarian superficial epithelium in senile female rats. Design: Fifty female rats at 15 months of age and with irregular estrous cycles were selected and randomly divided into five experimental groups containing equal numbers of animals in each: GPROP, control group receiving vehicle only; GE0.05mg, group receiving conjugated equine estrogens (CEE) at a dose of 50 ìg/kg; GE0.5mg, group receiving CEE at 500 ìg/kg; GE1mg, group receiving CEE at 1 mg/kg; and GE2mg, receiving CEE at 2 mg/kg. The length of treatment was 21 days. After this period, the animals were anesthetized and the ovaries were fixed in 10% formaldehyde and processed for routine histology. Histomorphology was analyzed by light microscopy, and histomorphometrics were evaluated using the Imagelab program. RESULTS: In the GPROP and GE0.05mg groups, the superficial epithelium of the ovary had a simple cuboidal shape, and as the estrogen dose increased, the epithelium thickened, with pseudo-stratified or stratified epithelium appearing in the GE2mg group. The animals in the group given the highest estrogen dose (GE2mg) showed the thickest ovarian epithelium and the largest perimeter and surface area of the surface ovarian epithelium (P < 0.01). However, the difference in epithelium thickness between the GE0.5mg and GE1mg groupswas only slight. CONCLUSION: Our data suggest that CEE at a dose of 2 mg/kg may induce marked proliferation of rat ovarian epithelium.Objetivo: Avaliar o efeito de diferentes concentracoes de estrogenio sobre o epitelio superficial do ovario de ratas senis. Foram empregadas cinquenta ratas adultas com15 meses de idade e com ciclos irregulares, sendo aleatoriamente dividas em cinco grupos com o mesmo numero de animais: GPROP - controle (veiculo); GE0,05mg - Estrogenios Conjugados Equinos 50 ƒÊg/Kg (ECE); GE0,5mg - ECE 500 ƒÊg/Kg; GE1mg - ECE 1 mg/Kg; GE2mg - ECE 2mg/Kg. As ratas foram tratadas por gavagem durante 21 dias. Apos este periodo, os animais foram anestesiados e os ovarios foram fixados em formol 10% e submetidos a tecnica histologica convencional e corados pelo HE. O aspecto morfologico foi analisado em microscopia de luz e a histomorfometria foi avaliada usando o programa imagelab. Nos grupos GPROP and GE0,05mg, o epitelio superficial do ovario era cubico simples e conforme o aumento da dose de estrogenio, houve espessamento do epitelio ovariano com presenca de epitelio pseudo-estratificado ou estratificado no GE2mg. Os animais do grupo que recebeu a maior dose de estrogenios (GE2 mg) apresentaram a maior area, espessura e perimetro do epitelio superior ovariano comparado aos outros grupos (P<0.01). Contudo, houve pequena variacao da espessura entre o GE0,5mg e o GE1mg nos parametros histomorfometricos analisados. Nossos dados sugerem que a dose de 2mg de ECE pode induzir a proliferacao acentuada aumento de espessura e area do epitelio superficial do ovario de ratas senis.TEDEBV UNIFESP: Teses e dissertaçõe