To determine whether prohibitin expression patterns correlated with the differentiated status of the cells, prohibitin and P450scc were immunolocalized in ovarian tissue sections from rats treated with eCG plus NRS. As shown in Figure 3A (see Table 1), prohibitin immunostaining was predominantly confined to the granulosa cells, whereas the theca-interstitial cells showed low staining patterns within the preantral follicles. In contrast, immunofluorescence labeling for P450scc was confined to the belt-like regions of the interstitial cells (Fig. 3B). The theca cells showed low immunoreactivity in the preantral follicles for this protein (Fig. 3A), whereas the granulosa cells were clearly devoid of P450scc (Fig. 3B).
As the follicle developed toward early and large antral stages, the theca-interstitial cells showed more intense fluorescent signals for prohibitin and P450scc, respectively (Fig. 3, C-F). The granulosa cells of early antral follicles revealed a gradient-like expression pattern for prohibitin, whereas immunostaining for P450scc in mural granulosa cells was evident (Fig. 3, C and D).
FIG. 4. Immunolocalization of prohibitin (red) and TUNEL labeling (brown precipitate) in the rat ovary. Immature rats were treated with eCG (24 h) plus anti-eCG (24 h), and ovaries were processed for immuno-histochemical and TUNEL analyses. Using adjacent paraffin sections, cell death (A, C, and E) and prohibitin protein (B, D, and F), were detected with corresponding specific antibody and TUNEL method, respectively. Arrows denote nuclear translocation of prohibitin. Photomicrographs B, D, and F are high magnifications of the insets.