• Development and Reproduction
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• v.2 no.1
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• pp.29-37
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• 1998

To investigate the role of oviductal environment in early mammalian development, we examined the effects of bovine oviductal fluid (bOF) on the development of mouse 2-cell embryos in vitro. All of the embryos cultured in medium containing 5% or more of bOF underwent degeneration after 48 hr, whereas only 5% of embryos cultured in the absence of bOF degenerated. When bOF was heated at 65 \circ C for 30 min and then added to the culture medium, the embryotoxic effect of bOF was not removed at all such that none of the embryos remained alive after 48 hr. However, when bOF heated at 90 \circ C for 30 min was added to the culture, nearly most (95%) of embryos was alive. Similarly, pretreatment of bOF with 0.1% chymotrypsin for 1 hr or overnight following heating at 65 \circ C resulted in the development of 95.5% of mouse 2-cell embryos to early blastula after 48 hr culture in the presence of treated bOF. Interestingly addition of an anti-oxidant removed the evbryotoxic effect of bOF so that 91.0% of 2-cell embryos developed to morulae or blastulae in the presence of both 5% bOF and 10 mM of glutathione (GSH) after 48 hr culture. Neither oxidized form of GSH (GSSG) nor other antioxidants, however, could support the embryonic development in the presence of bOF. From these results, it is suggested that bOF contains a protein-like factor(s) which becomes embryotoxic by exposing in vitro, probably via oxidation reaction.