Efecto de la administración de diferentes dosis de gonadotropina menopáusica humana (hMG) sobre la respuesta ovárica en cobayas

Abstract

The aimed of this study was to evaluate the effect of the administration of Human menopausal gonadotropin (hMG) in different doses on the ovarian response in guineapigs, with prior synchronization of the estrous cycle. A total of 18 female guineapigs with an average age of 80 ± 15 days, weight about of 800 to 1150 grams, were used, under to 10 days adaptation process. 3 experimental groups were formed, which were synchronized for 15 days with progesterone (P4); starting on the last day of P4 administration and for 3 consecutive days, hMG was administered intraperitoneally at different doses, 5, 10, and 15 IU/kg/day. The administration of hMG significantly increased the number of corpora lutea (CLs) in all groups, in addition to the total number of recovered structures; however, there were no significant differences in the number of CLs observed, on the surface of the ovary, or in the structures recovered between the different doses of hMG. The number of the structures classified as suitable was higher in all groups, likewise, the proportion between morulas and blastocysts considered suitable was different between groups, all groups showed a higher proportion of morulas vs. the number of blastocysts collected on the wash day. The diameter of the follicles was affected by the administration of different doses of hMG, showing a greater follicular diameter in the groups with higher doses of hMG vs. the lowest dose group. No significant differences were evident in the vaginal membrane opening; as well as ovarian volume, size of corpora lutea and number of follicles. The results obtained suggest that the application of hMG has a direct effect on the ovarian response and therefore on the number of embryos recovered. This response is due to the high number of corpora lutea observed on the day of collection, however, this effect is dose independent.