Location of oocyte-specific linker histone in pig ovaries at different developmental stages postpartum

This study was conducted to determine the location of oocyte-specific linker histone (H1foo) in pig ovaries at different developmental stages postpartum using histologic, immunohistochemical, and immunofluorescent protocols. The pig ovaries were divided into three periods: proliferation of oogonia (P1, 3 days postpartum), slow growth of follicles (P2, from 40 days to 60 days postpartum), and rapid growth of follicles (P3, from 72 days to 165 days postpartum). With the development of the pig ovary, the boundary between the cortex and medulla gradually became obvious, and the cortex became thinner while the medulla thickened. The rete ovarii could only be observed in P1. The number of oogonia gradually declined after birth, whereas primordial follicles and early growing follicles all underwent an increasing trend followed by a decreasing trend. Developing antral follicles and antral follicles were first observed in 72 and 95 days postpartum, respectively. Both the immunohistochemistry and immunofluorescence detection showed that H1foo was mainly located in the cytoplasm of oogonia and apoptotic oogonia, as well as in the ooplasm of follicles and apoptotic follicles. Moreover, with the development of the pig ovary, the range of the positive signals became larger.