Apoptosis in granulose cells induced by intrafollicular peptide

Ovarian follicular fluid peptide (OFFP) purified from sheep ovaries has been earlier shown to induce degeneration of ovarian follicles in mice. In the present study, whether the effect of OFFP on granulosa cells was similar to apoptosis was studied using three parameters. Immature mice injected with pregnant mare serum gonadotropin on day 0 were administered with 10 or 20 μg of OFFP on day 1 and autopsied on day 2. The granulosa cells were collected from the ovarian follicles. The presence of apoptotic bodies were observed by staining the cells with acridine orange. DNA profiles of DAPI-stained cells analysed by flow cytometry also revealed apoptotic response to OFFP. Furthermore, agarose gel electrophoresis of low molecular weight DNA fraction extracted from the cells of OFFP-treated animals confirmed ladder formation and induction of apoptosis and not necrosis in granulosa cells. In conclusion, all the three parameters indicated apoptotic changes in granulosa cells of ovarian follicles in .mice treated with OFFP. The effect of OFFP seems to be exerted directly on the granulosa cells showing its autocrine role in the process of follicular atresia. This is discussed in the light of other intra/extra ovarian factors.