Effect of fetal age and method of recovery on isolation of preantral follicles from bovine ovaries

摘要

Enzymic and mechanical methods of preantral follicle recovery were compared. Fetal ovaries were obtained from cows at 150-270 days of pregnancy, and 135 521 preantral follicles at different stages of development were studied. The dissociation of ovaries with a mechanical procedure resulted in an average of 938.16 preantral follicles. In contrast, 3715.56 follicles were obtained when enzymatic digestion was used (P = 0.0001). Histological evaluation confirmed follicular stages and demonstrated thatboth mechanical and mechanical-enzymatic procedure did not affect the cellular integrity of the follicles. Granulosa cell-oocyte complexes surrounded by a basal membrane were considered as preantral follicles. The proportion of different stages of isolated preantral follicles was correlated with fetal age (P = 0.0001). Tertiary follicles were identified at 210 days of pregnancy. The results confirmed the observation that follicular development and atresia are initiated during fetal development.