Cultivo in vitro de folículos pré-antrais caprinos em meio suplementado com os hormônios folículo estimulante (FSH) e luteinizante (LH). / In vitro culture of goat preantral follicles in the middle supplemented with follicle stimulating hormone (FSH) and luteinizing hormone (LH).

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

19/07/2007

RESUMO

The aims of the present study were to investigate the effects of Luteinizing Hormone (LH) alone or in association with Follicle Stimulating Hormone (FSH) on survival, activation and growth of caprine primordial follicles using histological and ultrastructural studies. To this end, pieces of caprine ovarian cortex were cultured for 1 or 7 days, at 39oC in an atmosphere containing 5% CO2, in Minimum Essential Medium (MEM - control medium) supplemented with different concentrations of LH (1, 5, 10, 50 or 100 ng/mL experiment 1). In experiment 2, control medium was supplemented with FSH (50 ng/mL) and different concentrations of LH (1, 5, 10 or 50 ng/mL). Small fragments from non-cultured ovarian tissue as well as from those cultured for 1 or 7 days in a specific medium were processed for classical histology and transmission electron microscopy (TEM) to evaluate follicular integrity and to calculate the percentages of normal follicles. Additionally, effects of FSH on oocyte and follicle diameter of cultured follicles were evaluated. The results showed that after 7 days of culture, the presence of LH (10, 50 or 100 ng/mL) in culture media significantly increased the percentages of developing follicles (P<0,05). In addition, fragments cultured in media supplemented with FSH alone or FSH plus LH had higher percentage of developing follicles after one and seven days culture compared with control (P<0,05). At the end of culture period, 1 and 5 ng/mL LH increased follicular diameter, while additon of 1, 5 or 10 ng/mL LH increased oocyte diameter (P<0,05). In association with FSH, LH (1 and 5 ng/mL) increased follicular diameter. With regard to follicle survival, low doses of LH (1 ng/mL) kept follicle viability similar to day 0 and control medium after 7 days culture. However, higher concentrations of LH (5, 10, 50 e 100 ng/mL) induced atresia in goat follicles. Culture of ovarian cortex for 7 days in medium supplemented with FSH alone or FSH plus 1ng/mL LH kept ultrastructural characteristics of follicles similar to day 0. In conclusion, addition of low concentrations of LH (1 ng/mL) associated or not with FSH maintain goat follicles ultrastructural integrity, but LH in doses higher than 5 ng/mL induces atresia in goat preantral follicles.

ASSUNTO(S)

folículo pré-antral caprino lh fsh reproducao animal preantral follicle caprine in vitro culture fsh lh cultivo in vitro

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