Isolation and in vitro growth of sheep preantral follicles

Methods of producing developmentally competent human oocytes from the culture of preantral follicles are being developed. The aim of this study was to develop a method for the isolation of ovine preantral follicles and estimate the effect of different supplements on follicle growth. Preantral follicles were isolated from fresh ovarian tissue following collagenase digestion and microdissection. Isolated follicles were embedded in agar gel and cultured in alpha MEM supplemented with serum and containing: i) FSH; ii) FSH and hypoxanthine; iii) dbcAMP; iv) no supplements (control). No significant difference between the various supplements was observed in the growth rate of follicles which remained viable after seven days of culture. The presence of theca/stroma cells seemed to have a positive effect on the preservation of the follicular structure and antrum formation. Further experiments are required to optimise the isolation procedure and study the role of various supplements in a serum-free system.