We examined effects of co-culture with human oviduct epithelial cells (HOEC) on the development of mouse and human embryos from early embryonic stage to late morula or blastocyst stage (LM or B). In human, embryos were transferred and pregnancy
rate was
investigated. The HOEC, collected from surgically removed fallopian tube, were cultured in medium-199 supplemented with 20% fetal cord serum (FCS). The HOEC were characterized by using immunocytochemical staining with anticytokeratin antibody and
then
used for cultures of mouse and human embryos. Results obtained from co-culture system were as follows. Development rate of mouse embryos was improved by co-culture system at late developmental stage (p<0.025). Human supernumerary embryos remained
after
transfer, unsuitable for freezing because of their poor quality, were co-cultured for 72hrs. Co-culture (78.79%) or conditioned medium (78.26%) system improved the development rate, significantly, in comparision with control (11.11%) (p<0.001).
Co-cultured (85.71%) human zygotes for 24hrs showed the better development rate in comparision with control (50.00%) (p<0.01). When we transferred embryos cultured with the HOEC to patients, we obtained one pregnancy. Co-cultured human zygotes
for
24hrs
showed the better quality and viability for the replacement in comparision with control (p<0.01). In addition, improved pregnancy rate was obtained. Our results suggest that the co-culture system can rescue early degenerating embryos by improving
early
development and yield a resonable number of blastocyst for the appropriate replacement. The effect provided by cultured HOEC is not species specific for the development of embryos and it can be used to overcome in vitro blocks for the
development.
And
also the co-culture system offers the possibility to freeze embryos at blastocyst stage which is more sucessful stage for the freezing. The HOEC monolayer may provide some stimulus via specific factor, which is unknown, to the development of
embryos.
Our results showed that the co-culture system with HOEC can be an alternative to conventional culture system.
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