Studies on the mechanism of follicle rupture upon ovulation in vertebrates

本研究旨在阐明脊椎动物卵泡破裂对排卵的影响机制。利用青冈鱼、水稻和哺乳动物，如猪、小鼠和大鼠，我们得到了以下结果：(1)猪卵巢卵泡中存在缓激肽产生系统的所有成分以及最终产物缓激肽。此外，缓激肽B2受体在所有生长卵泡的颗粒细胞和膜细胞中均有定位。用缓激肽处理猪卵巢颗粒细胞后，基质金属蛋白酶-20的表达增强，提示其参与了缓激肽诱导的排卵过程。(2)本研究在哺乳动物卵巢中发现了一种新型的基质金属蛋白酶-23，并克隆了人基质金属蛋白酶-23的基因。分子生物学和生化特性表明，该基质金属蛋白酶参与卵泡发育过程，而不是排卵过程。(3)以青冈鱼卵巢为材料，分离得到8个基质金属蛋白酶基因克隆。原位杂交和体外排卵实验表明，MT2-MMPs可能参与了该物种的排卵过程。

In this study, we aimed to elucidate the mechanism of follicle rupture upon ovulation in vertebrate species. Using the medaka fish Oryzias latipes and mammals, such as pig, mouse and rat, we obtained following results:(1) We showed the occurrence of all components for the bradykinin-producing system as well as final product bradykinin in the porcine ovarian follicles. Furthermore, the localization bradykinin B2 receptor in both granulosa and theca cells of all growing follicles was demonstrated. Treatment of porcine ovarian granulosa cells with bradykinin resulted in the enhanced expression of matrix metalloproteinase-20, suggesting its involvement in the bradykinin-induced ovulation.(2) We discovered a novel type of matrix metalloproteinase, MMP-23, in the mammalian ovary, and human MMP-23 cDNA were cloned in this study. Molecular biological and biochemical characterizations strongly suggest that this MMP is involved in the process of follicular development rather than ovulation.(3) Using the medaka fish ovary, 8 MMP cDNA clones were isolated. Studies using in situ hybridization and in vitro ovulation experiments indicated that MT2-MMP is probably involved in the ovulation of this species.