Maturation, Aging and Death in Reproductive Tissues
(T641) CONNEXIN-43 HAS RELATION TO REGULATION OF GRANULOSA CELL APOPTOSIS DURING ATRESIA IN PIG OVARIAN FOLLICLES.
Cheng, Yuan1, Inoue, Naoko2, Matsuda-Minehata, Fuko1, Goto, Yasufumi1, Maeda, Akihisa1, Li, Junyou1, Manabe, Noboru1, 1 University of Tokyo, Ibaraki-Iwama, Japan2 Nagoya University, Nagoya, Japan
ABSTRACT- Gap junctions contain channels that connect neighboring cells by allowing the movement of molecules smaller than 1,000 Da. These gap junctions are formed by connexins, and play a crucial role in the regulation of apoptotic cell death. In granulosa cells of ovarian follicles, connexin-43 (Cx43) is expressed. To determine the regulatory mechanism of granulosa cell apoptosis during follicular atresia, we examined changes in the expression and localization of Cx43 mRNA and its protein in granulosa cells of porcine ovaries during follicular atresia. Stages of follicular atresia were assessed by histochemical TUNEL staining and by the ratio of progesterone and estradiol levels in follicular fluid measured by RIA. As a result, both Cx43 mRNA and protein were detected in granulosa cells of healthy, early atretic and progressed atretic follicles, but not detected in primordial or primary follicles. Western blotting showed that Cx43 protein was expressed most strongly in isolated granulosa cells prepared from healthy follicles, but only trace or slight expression was noted in those from progressed atretic follicles. That is to say, in the follicular atresia, Cx43 protein expression level was decreased. These findings indicate that Cx43 is related to granulosa cell apoptosis during follicular atresia in pig ovaries.
KEY WORDS: connexin-43, granulosa cell, apoptosis, pig ovary