Roles of oviductal proteins on preimplantation embryo development

Abstract

Somatic cell-embryo coculture enhances embryo development invitro by producing embryotrophic factor(s) and/or removing harmfulsubstances from the culture environment. Accumulating evidencesuggested that embryos interact with the female reproductivetract to modulate the microenvironment conducive to successfulembryo development. Yet, the underlying molecular mechanismson how somatic cells interact with embryos remain largely unknown.By using suppression subtractive hybridization, we identifieda number of mouse oviductal genes that were up-regulated inthe presence of developing preimplantation embryos but not oocytes.These up-regulated genes were found to be highly expressed inthe oviduct. Some of them were also expressed in other tissuesas well. Interestingly, at least the expression of three ofthem, complement component-3 (C3), demilune parotid protein(Dcpp) and microsomal epoxide hydrolase (mEH or Ephx1), wereincreased/maintained at high levels in the oviduct during pregnancy,and were partly regulated by steroid hormones. Oviductal C3and Dcpp were embryotrophic in vitro, and Ephx1 was able toremove reactive oxygen species present in the co-culture medium.Their embryotrophic effects could be nullified by addition ofeither neutralizing antibody or specific inhibitors. Our resultssupport the notion that somatic cell coculture may enhance embryodevelopment partly via enhancing embryo developmental potentialand/or removing deleterious substances in the environment.