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Present study was aimed to verify the role of insulin and TNF-α in development of preimplantation embryos. Mouse morula were cultured for 40 hr in the presence or absence of insulin(400 ng/ml) and TNF-α (50 ng/ml). The morphological development, cell number of blastomeres per blastocyst, and mitogen activated protein kinase(MAPK) activity were examined. The developmental rate and cell number per embryo were the highest in insulin treatment group and the lowest in TNF-α treatment group. There was no significant difference in developmental rate between control and insulin plus TNF-α group. Taken together, it suggested that TNF-α impaired embryonic development and that insulin rescued developmental impairment imposed by TNF-α. In blastocysts, insulin treatment significantly increased MAPK activity. TNF-α decreased the MAPK activity in a concentration-dependent manner. In the TNF-α(50 ng/ml) -primed embryos, activation of MAPK by insulin was attenuated. In conclusion, these results suggest that there was a cross talk between insulin and TNF-α by means of activation of MAPK in preimplantation embryos and that insulin might rescue damage of embryos exposed to TNF-α.
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