An explanation of these observations is that during the period of follicle culture, the oocytes are able to translate or posttranslationally modify essential proteins or to transcribe mRNAs essential for further embryonic development. In the present study, the percentage of embryos that developed to 4 cells or more during the first 48 h of culture was greater in the control group (68.6%) than in the treatment group (54.6%). The higher cleavage rate in the control oocytes may arise from the process of selection of directly aspirated oocytes prior to maturation. Oocytes from nonatretic follicles were aspirated and selected on morphological criteria for culture. In contrast, the selection for the treatment group was imposed at the follicle culture stage. buy ortho tri-cyclen online
Although only healthy, nonatretic follicles were isolated for culture, it seems that judgment based solely on follicle morphology may not be a precise method for selection of nonatretic oocytes. There are many apparently normal follicles that may include atretic oocytes. In addition, the process of atresia itself consists of different stages. Further research on antral follicle culture and the role of specific factors that support follicle growth is necessary. In conclusion, intact antral follicle culture is an efficient method for maintaining bovine oocytes in meiotic arrest for periods up to 48 h. The results suggest that during antral follicle culture, the enclosed oocytes may acquire a greater developmental competence than do oocytes matured directly following aspiration.