Reproduction Abstracts

Introduction: During follicular development in mammalian ovaries, the majority of follicles undergo atresia. One of the characteristics of this process is apoptotic cell death in granulosa cells. Death ligands and receptors, including Fas ligand (FasL) and Fas, have been detected in follicles and also demonstrated to be capable of inducing apoptosis in follicular cells. Decoy receptor 3 (DcR3) competes with Fas to bind FasL but lacks intracellular death domains, thus inhibiting the induction of apoptosis by FasL.

Materials and methods: Total RNA and proteins were extracted from granulosa cells of porcine tertiary follicles at healthy, early atretic and progressed atretic stages. The localization and expression of pDcR3 mRNA was demonstrated by in situ hybridization and real time RT-PCR, respectively. The localization and expression of pDcR3 protein was demonstrated by immunohistochemistry and western blot respectively.

Results and discussion: In situ hybridization showed that pDcR3 mRNA expression was confirmed in granulosa cells of healthy. Quantitative RT-PCR showed that the expression of pDcR3 mRNA was extremely weaker in granulosa cells of early atretic follicles than those of healthy follicles. No pDcR3 mRNA was detected in granullosa cells of progressed atretic follicle. Protein expression profiles were similar to the profiles of mRNA. These findings suggest that DcR3 plays a significant role in the regulation of apoptosis in granulosa cells during atresia.