Epidermal growth factor induces Bcl-xL gene expression and reduces apoptosis in porcine parthenotes developing in vitro

The aim of this study was to determine the interactive effects of bovine serum albumin (BSA) and epidermal growth factor (EGF) on the viability and development of porcine presumptive diploid parthenotes developing in vitro. The addition of 0.1 and 0.4% BSA to the culture medium enhanced the development of 4-cell parthenotes to the blastocyst stage but EGF had no effect. However, while BSA also increased cell numbers, it did so only when EGF was also present. Either agent on its own had no effect. Similarly, apoptosis in the blastocysts was not influenced by either agent on its own but was reduced when both BSA and EGF were present. Furthermore, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that EGF enhanced the mRNA expression of Bcl-xL in the presence of 0.4% BSA but BSA and EGF alone had no effect. EGF and/or BSA did not influence Bak gene expression in the blastocyst stage parthenotes. These results suggest that EGF and BSA synergistically enhance Bcl-xL gene expression, which may result in a net increase in cell number in porcine presumptive diploid parthenotes developing in vitro. (C) 2003 Wiley-Liss, Inc.