Otani N, Minami S, Yamoto M, Shikone T, Otani H, Nishiyama R, Otani T, Nakano R
Department of Obstetrics and Gynecology, Wakayama Medical College, Japan.
J Clin Endocrinol Metab. 1999 Oct;84(10):3845-51. doi: 10.1210/jcem.84.10.6025.
In human ovaries, angiogenesis is known to be associated with the development of follicles and the formation of the corpus luteum (CL). A complex vascular network is formed within the thecal cell layer during follicular growth, and rapid neovascularization occurs toward the granulosa cell layer after ovulation. Vascular endothelial growth factor (VEGF) is a multifunctional cytokine, stimulating endothelial cell growth and enhancing microvascular permeability. A specific receptor for VEGF, fms-like tyrosine kinase (Flt-1), is expressed in vascular endothelial cells that mediates the action of VEGF. We examined the localization and expression of VEGF and Flt-1, using an immunohistochemical technique and RT-PCR analysis, in human follicles and corpora lutea during the normal menstrual cycle and early pregnancy. We measured concentrations of VEGF in extracts of human CL using an enzyme-linked immunosorbent assay during the luteal phase and early pregnancy. Immunostaining for VEGF was observed in granulosa cells from small antral follicles to preovulatory follicles. The staining was detected in thecal cells from medium-sized to preovulatory follicles. The intensity of the staining was gradually increased as a follicle grew. Flt-1 was localized in granulosa and thecal cells of preovulatory follicles as well as in endothelial cells. In the human CL, the intense staining for VEGF was observed in granulosa and thecal lutein cells, especially in the midluteal phase. The immunostaining for Flt-1 was faint in endothelial cells in the CL, whereas it was distinct in granulosa and thecal lutein cells. The concentrations of VEGF in lutein extracts were high in the early and midluteal phases and tended to decrease toward the late luteal phase. During early pregnancy, a measurable amount of VEGF was detected. RT-PCR analysis demonstrated that messenger ribonucleic acids encoding VEGF121, VEGF165, and Flt-1 were expressed in the CL. These results suggest that VEGF might have an autocrine role in the ovulatory process and luteal function as well as a paracrine role in angiogenesis.
在人类卵巢中，血管生成与卵泡发育及黄体（CL）形成有关。在卵泡生长过程中，卵泡膜细胞层内形成复杂的血管网络，排卵后朝向颗粒细胞层会发生快速的新生血管形成。血管内皮生长因子（VEGF）是一种多功能细胞因子，可刺激内皮细胞生长并增强微血管通透性。VEGF的特异性受体，即fms样酪氨酸激酶（Flt-1），在介导VEGF作用的血管内皮细胞中表达。我们使用免疫组织化学技术和逆转录聚合酶链反应（RT-PCR）分析，研究了正常月经周期和妊娠早期人卵泡及黄体中VEGF和Flt-1的定位与表达。我们在黄体期和妊娠早期使用酶联免疫吸附测定法测量了人黄体提取物中VEGF的浓度。在从小窦状卵泡到排卵前卵泡的颗粒细胞中观察到VEGF免疫染色。在中等大小到排卵前卵泡的卵泡膜细胞中检测到染色。随着卵泡生长，染色强度逐渐增加。Flt-1定位于排卵前卵泡的颗粒细胞和卵泡膜细胞以及内皮细胞中。在人黄体中，在颗粒黄体细胞和卵泡膜黄体细胞中观察到VEGF的强染色，尤其是在黄体中期。黄体中内皮细胞的Flt-1免疫染色较弱，而在颗粒黄体细胞和卵泡膜黄体细胞中则明显。黄体提取物中VEGF的浓度在黄体早期和中期较高，在黄体后期趋于下降。在妊娠早期，检测到可测量的VEGF量。RT-PCR分析表明，编码VEGF121、VEGF165和Flt-1的信使核糖核酸在黄体中表达。这些结果表明，VEGF可能在排卵过程和黄体功能中具有自分泌作用，以及在血管生成中具有旁分泌作用。
