Association between insulin-like growth factor-I, thyroxine and follicle stimulating hormone on the survival and in vitro development of caprine preantral follicles

The aim of this study was to investigate the influence of the interaction between follicle stimulating hormone obtained from Human Pituitary (hFSH; 10 ng/mL), Insulin-like Growth Factor Type 1 (IGF-I; 100 ng/mL) and thyroxine (T 4 ; 10, 20 ng/mL) on survival, activation and growth of preantral follicles (PAF) cultured in vitro. Fragments of ovarian cortex collected from 17 nonpregnant adult goats underwent different treatments that included -MEM + medium, IGF-I, hFSH, T 4 and were processed for classic histology and transmission electron microscopy. The results showed a reduction in the percentage of normal follicles, after one and seven days of culture in media -MEM + (cultured control), T 4 (10)/IGF-I, T 4 (20)/IGF-I/hFSH and in media -MEM + , IGF-I/hFSH, T 4 (20)/IGF-I/hFSH, T 4 (20)/IGF-I/hFSH , when compared to the non-cultured control. However, the medium containing T 4 (20)/hFSH showed a follicular survival rate higher than the other treatments, when cultured for seven days. It was also observed that the follicular diameter did not change when cultured in this medium, when compared to the control (non-cultured). The ultrastructural analysis confirmed the integrity of follicles cultured in a medium containing T 4 (20)/hFSH. In conclusion, the medium containing T 4 (20)/hFSH showed the best results, when evaluating the survival, growth and ultrastructural aspects of caprine preantral follicles cultured in vitro.