Trau Heidi A, Davis John S, Duffy Diane M
Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia.
Veterans Affairs Nebraska-Western Iowa Health Care System and Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, Nebraska.
Biol Reprod. 2015 Jan;92(1):15. doi: 10.1095/biolreprod.114.123711. Epub 2014 Nov 5.
Rapid angiogenesis occurs as the ovulatory follicle is transformed into the corpus luteum. To determine if luteinizing hormone (LH)-stimulated prostaglandin E2 (PGE2) regulates angiogenesis in the ovulatory follicle, cynomolgus macaques received gonadotropins to stimulate multiple follicular development and chorionic gonadotropin (hCG) substituted for the LH surge to initiate ovulatory events. Before hCG, vascular endothelial cells were present in the perifollicular stroma but not amongst granulosa cells. Endothelial cells entered the granulosa cell layer 24-36 h after hCG, concomitant with the rise in follicular PGE2 and prior to ovulation, which occurs about 40 h after hCG. Intrafollicular administration of the PG synthesis inhibitor indomethacin was coupled with PGE2 replacement to demonstrate that indomethacin blocked and PGE2 restored follicular angiogenesis in a single, naturally developed monkey follicle in vivo. Intrafollicular administration of indomethacin plus an agonist selective for a single PGE2 receptor showed that PTGER1 and PTGER2 agonists most effectively stimulated angiogenesis within the granulosa cell layer. Endothelial cell tracing and three-dimensional reconstruction indicated that these capillary networks form via branching angiogenesis. To further explore how PGE2 mediates follicular angiogenesis, monkey ovarian microvascular endothelial cells (mOMECs) were isolated from ovulatory follicles. The mOMECs expressed all four PGE2 receptors in vitro. PGE2 and all PTGER agonists increased mOMEC migration. PTGER1 and PTGER2 agonists promoted sprout formation while the PTGER3 agonist inhibited sprouting in vitro. While PTGER1 and PTGER2 likely promote the formation of new capillaries, each PGE2 receptor may mediate aspects of PGE2's actions and, therefore, LH's ability to regulate angiogenesis in the primate ovulatory follicle.
随着排卵卵泡转变为黄体，快速血管生成发生。为了确定促黄体生成素（LH）刺激产生的前列腺素E2（PGE2）是否调节排卵卵泡中的血管生成，食蟹猴接受促性腺激素以刺激多个卵泡发育，并用绒毛膜促性腺激素（hCG）替代LH峰以启动排卵事件。在注射hCG之前，血管内皮细胞存在于卵泡周围基质中，但不存在于颗粒细胞之间。注射hCG后24 - 36小时，内皮细胞进入颗粒细胞层，这与卵泡PGE2水平升高同时发生，且在排卵前，排卵大约发生在注射hCG后40小时。在卵泡内给予PG合成抑制剂吲哚美辛并补充PGE2，以证明吲哚美辛在体内单个自然发育的猴卵泡中阻断了卵泡血管生成，而PGE2恢复了卵泡血管生成。在卵泡内给予吲哚美辛加一种对单一PGE2受体具有选择性的激动剂，结果显示PTGER1和PTGER2激动剂最有效地刺激了颗粒细胞层内的血管生成。内皮细胞追踪和三维重建表明，这些毛细血管网络通过分支血管生成形成。为了进一步探索PGE2如何介导卵泡血管生成，从排卵卵泡中分离出猴卵巢微血管内皮细胞（mOMECs）。mOMECs在体外表达所有四种PGE2受体。PGE2和所有PTGER激动剂均增加mOMEC迁移。PTGER1和PTGER2激动剂促进芽生形成，而PTGER3激动剂在体外抑制芽生。虽然PTGER1和PTGER2可能促进新毛细血管的形成，但每种PGE2受体可能介导PGE2作用的不同方面，因此也介导了LH调节灵长类排卵卵泡血管生成的能力。
