Proliferating Cell Nuclear Antigen (PCNA) Localization in the Ovaries of Buffalo, Dog and Pig by Immunohistochemistry

Background: It was expected from the previous studies that the immune histochemical staining for PCNA within follicular cells altered depending on the stage of follicular growth. Therefore, we aimed at determining the expression of proliferating cell nuclear antigen protein (PCNA) in the buffalo, dog and pig ovaries. Methods: The localization of PCNA was demonstrated in formalin fixed, paraffin embedded tissue sections of buffalo, dog and pig ovaries using primary mouse monoclonal anti-PCNA antibody. Result: Staining for PCNA was not observed in pregranulosa cells but observed in oocytes of primordial follicles. In primary to early secondary follicles, in oocytes and in few granulosa cells the positive staining was detected. The late secondary preantral follicles and actively growing small to large antral follicles showed strong PCNA labelling in the layers of granulosa and theca cells. PCNA staining was expressed in nuclei of oocytes in preantral and small antral follicles. The follicles demonstrating advanced atresia showed mild to no PCNA labelled granulosa and theca cells. The results of our study demonstrated that follicular growth and development in ovaries may be effectively monitored by determining the rate of granulosa cell proliferation of PCNA.