[The Expression of Proto-Oncogene C-Erbb₂ and Its Role in the Initiation of Primordial Follicle Growth in Rat Ovary].

Little is known about the factors that control the initiation of growth of primordial follicles. The objective of the present study was to investigate the effect of c-erbB₂ on the onset of primordial follicle development, and whether c-erbB₂ mediates the effect of epidermal growth factor (EGF) in this process. We synthesized three pairs of siRNAs targeting the c-erbB₂ mRNA and transferred them into the newborn rat ovary cultured in vitro with Metafectene. After siRNAs transfection, the efficiency of siRNAs was tested by examining c-erbB₂ mRNA and protein levels. The level of c-erbB₂ mRNA was reduced by 49.6%, 46.7% and 82.6% respectively after transfecting siRNA1, siRNA2 and siRNA3, and the level of ErbB₂ protein also reduced remarkably after siRNA3 transfection. c-erbB₂ siRNA3 significantly inhibited the primordial follicle initiation and development; EGF augmented primordial follicles formation, but the effect was abolished by c-erbB₂ siRNA3. All of these results suggest that c-erbB₂ plays an important role in primordial follicle development and folliculogenesis initiation, and mediates the effect of EGF on primordial follicle development.