Steffl M, Schweiger M, Amselgruber W M
Department of Anatomy and Physiology of Domestic Animals, University of Hohenheim, Stuttgart, Germany.
Histol Histopathol. 2008 Jun;23(6):665-71. doi: 10.14670/HH-23.665.
Transforming growth factor-beta (TGF-beta) proteins are growth factors that have been shown to be involved in regulation of ovarian follicular development. Ovarian expression, activity and functional significance of TGF-beta1 and TGF-beta2 isoforms were extensively studied in most species. However, little is known about the biological role of TGF-beta3 previously shown to be expressed independently of the other two isoforms. Therefore, expression of TGF-beta3 mRNA and protein was evaluated by RT-PCR and immunohistochemistry, respectively, in porcine ovaries collected during different phases of the oestrus cycle. Results of RT-PCR analysis showed that TGF-beta3 mRNA is expressed throughout the oestrus cycle. The level of TGF-beta3 mRNA expression was found to be higher at metoestrus and dioestrus. Weak TGF-beta3 immunoreactivity was present in follicular epithelial cells and oocytes of preantral follicles in all stages examined. TGF-beta3 protein expression was exclusively present in theca interna cell layer of antral follicles, and was particularly prominent in large antral follicles. Immediately after ovulation, almost all theca cells outside of the granulosa cell layer were intensively stained with anti-TGF-beta3. Immunostaining of TGF-beta3 in theca lutein cells rapidly decreased during corpus luteum development. It is suggested that TGF-beta3 may play an important role in modulating theca cell function of pre- and postovulatory follicles of the pig.
转化生长因子-β（TGF-β）蛋白是一类生长因子，已被证明参与卵巢卵泡发育的调节。在大多数物种中，对TGF-β1和TGF-β2亚型的卵巢表达、活性及功能意义进行了广泛研究。然而，此前已证明TGF-β3独立于其他两种亚型表达，但其生物学作用却知之甚少。因此，分别采用逆转录聚合酶链反应（RT-PCR）和免疫组织化学方法，对发情周期不同阶段采集的猪卵巢中TGF-β3 mRNA和蛋白的表达进行了评估。RT-PCR分析结果显示，TGF-β3 mRNA在整个发情周期均有表达。在发情后期和间情期，TGF-β3 mRNA表达水平较高。在所检查的所有阶段，初级卵泡的卵泡上皮细胞和卵母细胞中均存在较弱的TGF-β3免疫反应性。TGF-β3蛋白表达仅存在于窦状卵泡的内膜细胞层，在大的窦状卵泡中尤为明显。排卵后立即观察到，几乎所有颗粒细胞层外的内膜细胞均被抗TGF-β3抗体强烈染色。在黄体发育过程中，黄体化内膜细胞中TGF-β3的免疫染色迅速减弱。提示TGF-β3可能在调节猪排卵前和排卵后卵泡的内膜细胞功能中发挥重要作用。
