Serum Deprivation-Induced Apoptosis in Cultured Porcine Granulosa Cells Is Characterized by Increased Expression of p53 Protein, Fas Antigen and Fas Ligand and by Decreased Expression of PCNA

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Although serum deprivation induces apoptosis in several cell lines, biochemical characterization of the apoptosis in primary granulosa cells (GCs) induced by serum deprivation has rarely been reported. In the present study, GCs from small follicles of porcine ovaries were precultured under a serum-containing condition for seven days, then stepped down to a serum-free condition and cultured for the subsequent two days. GCs were subjected to DNA fragmentation and immunoblot analyses. Data indicated that serum deprivation induced GC apoptosis characterized by DNA laddering, which was associated with decreased expression of proliferating cell nuclear antigen (PCNA) and increased expression of p53 protein, Fas antigen and Fas ligand. Serum deprivation also resulted in an increase in a 115kDa protein expression despite no detectable expression of a 66kDa c-myc protein. This suggests that serum removal from primary GCs may activate multiple apoptotic pathways such as a p53-associated pathway and a Fas-Fas ligand pathway.