Development of in vitro matured and fertilized bovine embryos cocultured with bovine oviductal epithelial cells obtained from oviducts ipsilateral tocystic follicles

The present experiment was conducted to clarify the effect of bovine oviduc tal epithelial cells (BOEC) collected from oviducts ipsilateral to cystic f ollicles (CFs) using an in vitro coculture system on the development of in vitro matured/fertilized (IVM/IVF) bovine embryos. In the first comparison, the effect of the presence of CF on the development of the embryos cocultu red with BOEC derived from the cows with CF (n = 18) and corpus hemorrhagic um (CH, n = 10) was examined. In the second comparison, the effect of the t ype of cyst [progesterone (P-4)-dominant; n = 9, estradiol-17 beta (E-2)-do minant; n = 5] on the development of the embryos cocultured with BOEC deriv ed from the cystic cows was examined. No difference was observed between CF and CH (control) groups in the mean developmental rates of embryos develop ed to greater than or equal to 2-cell (86.3% vs. 86.4%), 8-16 cells (53.0% vs. 56.2%), blastocyst (24.2% vs. 24.8%) and hatched blastocyst (12.0% vs. 14.6%). However, the blastocyst production rate was significantly different (P < 0.05) between the P-4-dominant (19.8%) and E-2-dominant (32.6%) groups . The rate of development from cleavage stage embryo to blastocyst was sign ificantly different between P,-dominant (22.9%) and E-2-dominant (37.9%) gr oups. Moreover, the blastocyst rate from 8-16 cells of E-2-dominant group ( 61.6%) was significantly higher than that of P-4-dominant one (39.5%). Thes e results indicate that the effects of BOEC collected from oviduct ipsilate ral to CFs on embryo development are variable, and the variability is close ly associated with the steroid hormone profiles of the follicular fluid. (C ) 1999 Elsevier Science B.V. All rights reserved.