Ovarian superstimulatory response and embryo development using a new recombinant glycoprotein with eCG-like activity in mice

Pharmacological ovarian control required for the implementation of artificial insemination and embryo-related technologies usually includes the use of eCG, naturally produced in pregnant mares. In this study, we report the superovulatory response and embryo development in mice obtained with a new glycoprotein with eCG-like activity (reCG) produced by recombinant DNA technology. A total of 150 females from three different mouse strains (C57BL/6J, BALB/cJ and B6D2F1/J) were subjected to a superstimulatory protocol consisting of 5 IU of natural eCG (n = 50), 5 IU of reCG (n = 50), or received a placebo (no-eCG, n = 50) by intraperitoneal route, followed by 5 IU of human chorionic gonadotropin 48 h later. Overall, no significant differences were observed in the total number of ova/zygotes (33.6 ± 2.4 vs 28.7 ± 2.6; P = NS) and viable ova/zygotes (31.5 ± 2.4 vs 25.8 ± 2.5; P = NS) collected per female among eCG and reCG treated females, respectively, which were greater (P < 0.05) than those obtained in no-eCG treated females (6.9 ± 0.7 and 5.9 ± 0.7, respectively). Zygotes derived from the three experimental groups (n = 2914) were subjected to in vitro culture until hatching 4.5 days post coitum (dpc). Regardless of the mouse strain, no differences were observed among eCG and reCG treated females for overall cleavage rate 1.5 dpc (58.5% vs 60.5%), development rate 3.5 dpc (47.2% vs 48.9%) and hatching rate 4.5 dpc (49.5% vs 54.5) (P = NS). Control females from no-eCG treated group showed lower cleavage and development rates (36.4% and 29.7%, respectively; P < 0.05). In conclusion, this study reports for the first time comparable superovulatory response and embryo development between recombinant and natural eCG treatment, which has important implications for reproductive technologies in several species.