Laboratory of Animal Molecular Genetics, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian 271018, China.
Gen Comp Endocrinol. 2012 Sep 1;178(2):314-22. doi: 10.1016/j.ygcen.2012.06.018. Epub 2012 Jun 23.
Connective tissue growth factor (CTGF) is a cysteine-rich, matrix-associated heparin-binding protein that is important in many cell types as a regulator of cell proliferation, angiogenesis, cell remodelling and other cellular processes. CTGF is necessary for normal follicle growth and luteinisation in mammals. The avian follicular hierarchy provides an excellent experimental model to study developmental events, particularly the role of cellular remodelling factors in the process of folliculogenesis. In this study, we examined CTGF expression and regulation in the hen ovary. CTGF expression was increased considerably as follicular development proceeds in pre-ovulatory follicles, peaking in expression at the time of ovulation. Immunohistochemistry revealed that CTGF protein was concentrated in the cytoplasm of follicular granulosa cells throughout the ovulation cycle. We isolated granulosa cells from the follicles at two key stages of the ovulation cycle (in terms of cellular alteration): during pre-ovulatory growth and during post-ovulatory regression. Follicle-stimulating hormone (FSH) and luteinising hormone (LH) inhibited CTGF expression in pre-ovulatory granulosa cells but stimulated CTGF expression in post-ovulatory granulosa cells. Moreover, TGFβ1 stimulated CTGF expression in both pre- and post-ovulatory granulosa cells. Nevertheless, TGFβ1 could rescue the inhibition of gonadotrophins on pre-ovulatory granulosa CTGF expression but could not further stimulate CTGF expression in gonadotrophin-treated post-ovulatory granulosa cells. The results of this study indicate that CTGF expression in avian granulosa cells is modulated by a combination of gonadotrophins and TGFβ1 according to the different stages of follicle maturation and degradation. The results also suggest that the gonadotrophic action on post-ovulatory follicles in the avian ovary differs from the gonadotrophin-induced luteinisation in mammals.
结缔组织生长因子（CTGF）是一种富含半胱氨酸的基质相关肝素结合蛋白，在许多细胞类型中作为细胞增殖、血管生成、细胞重塑和其他细胞过程的调节剂发挥重要作用。CTGF 是哺乳动物卵泡生长和黄体化所必需的。禽类卵泡层次结构为研究发育事件提供了一个极好的实验模型，特别是细胞重塑因子在卵泡发生过程中的作用。在这项研究中，我们研究了 CTGF 在母鸡卵巢中的表达和调节。在预排卵卵泡中，随着卵泡的发育，CTGF 的表达显著增加，在排卵时达到峰值。免疫组织化学显示，CTGF 蛋白在整个排卵周期中集中在卵泡颗粒细胞的细胞质中。我们从排卵周期两个关键阶段（从细胞改变的角度来看）分离出卵泡颗粒细胞：在排卵前生长期间和排卵后退化期间。卵泡刺激素（FSH）和黄体生成素（LH）抑制排卵前颗粒细胞中的 CTGF 表达，但刺激排卵后颗粒细胞中的 CTGF 表达。此外，TGFβ1 刺激排卵前和排卵后颗粒细胞中的 CTGF 表达。然而，TGFβ1 可以挽救促性腺激素对排卵前颗粒细胞 CTGF 表达的抑制作用，但不能进一步刺激促性腺激素处理的排卵后颗粒细胞中的 CTGF 表达。这项研究的结果表明，禽类颗粒细胞中 CTGF 的表达受促性腺激素和 TGFβ1 的组合调节，根据卵泡成熟和退化的不同阶段。结果还表明，禽类卵巢中促性腺激素对排卵后卵泡的作用与哺乳动物中促性腺激素诱导的黄体化不同。
