Effecf of EDTA on the Preimplantation Development of Mouse Embryos Fertilized in vitro

Abstract

The present study was undertaken to know whether EDTA exerts beneficial effect on the development of mouse embryos derived from eggs fertilized in vitro. The effect of EGTA was also examined. Superovulated eggs were collected from ICR and F1(C57BL×C3H)females and were inseminated with epididymal sperm obtained from ICR males. At 6hr after inseminaion, the eggs extruding 2nd polar body were transferred to the Whitten's medium with or without the chelating agents and then cultured further for 114hr. The development of ICR embryos beyond the 2-cell stage at 48 hr after insemination was significantly enhanced by the presence of 2.5-500μM EDTA. More than 90% of lCR embryos cultured in the medium containing 20-100μM EDTA developed into the blastocyst stage. On the other hand, only 27-31% of embryos cultured in the medium without EDTA developed to the blastocyst. Regardless of whether EDTA exists or not, most of the F1 embryos developed into blastocysts. EDTA added not later than 12hr after insemination remarkably improved the development beyond the 2-cell stage, but EDTA added at 36hr did not exert significant effect. The treatment with EDTA for 18hr from 6hr after insemination significantly enhanced the development, but the treatment for only 6hr did not. EGTA did not stimulate the development of embryos. These results indicate that the stimulating effect of EDTA on the development of embryos into blastocysts is remarkable at 12-24hr after insemination.