Histological and immunohistochemical study of apoptosis in granulosa cells of atretic ovarian follicles of adult albino rat

ABSTRACT

It is well known that during ovarian follicular development, the majority of follicles undergo atresia at various stages of their development. Recent studies have reported that the degenerative changes associated with atresia appear initially in the granulosa cell layer, and follicular atresia occurs by apoptosis, which is an essential physiological process. The present study aimed to examine granulosa cell apoptosis using different, histological, immunohistochemical, and biochemical methods. Fifteen adult female albino rats were used in this study. The rats were sacrificed and bilateral oophorectomy was carried out; the ovaries of rats were processed and paraffin sections were prepared for staining with H and E and also to study immunohistochemistry for apoptotic proteins such as caspase-3 and antiapoptotic proteins such as B-cell lymphoma-2 [Bcl-2]. Some ovarian specimens were processed by electrophoresis for DNA separation. Apoptosis in granulosa cell showed morphological characteristics, including nuclei with marginated chromatin, a single condensed pyknotic nucleus, multiple nuclear fragments, and apoptotic bodies containing variable amounts of chromatin. Moreover, apoptotic changes were detected by immunohistochemical staining in the form of increased staining intensity to caspase-3 [apoptotic protein] and decreased staining intensity to Bcl-2 [antiapoptotic protein], and also increased fragmentation of DNA, which was indicated by a ladder step appearance that was detected using DNA electrophoresis