The influence of insulin on the in vitro development of mouse and bovine embryos

To further investigate the role of insulin during preimplantation embryo development, we compared the effects of insulin on the development of mouse and bovine preimplantation embryos and on cell proliferation during culture in vitro in simplex media. The influence of insulin on the development of mouse zygotes was determined during cultivation in mSOF medium, alone or supplemented with glucose. Similarly, the effects of insulin on the bovine preimplantation embryo development were studied in mSOF medium. The addition of insulin into mSOF medium enhanced significantly the number of cells per mouse blastocyst. Moreover, when mSOF medium was supplemented with insulin and 0.2 mmol x l(-1) glucose, the percentage of hatched blastocysts and the mean cell number of mouse blastocysts were significantly higher. Insulin had no significant effect on the development of bovine embryos, produced by in vitro fertilization of in vitro matured oocytes. Neither the rates of developing embryos nor the mean number of cells in blastocysts were different in comparison with control embryos. Our results suggest that the in vitro development of mouse embryos could be enhanced by the addition of insulin to the culture medium and is further improved by the addition of glucose. In contrast to this our results indicate that insulin has no detectable beneficial effect on the preimplantation development of bovine embryos in mSOF medium.