Jung Hyo Young, Kim Woosuk, Hahn Kyu Ri, Nam Sung Min, Yi Sun Shin, Kwon Hyun Jung, Kang Min Soo, Choi Jung Hoon, Kim Dae Won, Yoon Yeo Sung, Hwang In Koo
Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 34134, South Korea.
Department of Anatomy, College of Veterinary Medicine, and Veterinary Science Research Institute, Konkuk University, Seoul 05030, South Korea.
Iran J Basic Med Sci. 2021 Jul;24(7):908-913. doi: 10.22038/ijbms.2021.56286.12556.
Prostaglandin E2 E-prostanoid 2 receptor (PGE2 EP2), downstream of cyclooxygenase-2 (COX-2), plays an important role in inflammatory responses, but there are some reports about synaptic functions of COX-2 and PGE2 EP2 in the hippocampus.
C57BL/6J mice were sacrificed at postnatal days (P) 1, 7, 14, 28, and 56 for immunohistochemical staining for EP2 and doublecortin as well as western blot for EP2. In addition, COX-2 knockout and its wild-type mice were euthanized for immunohistochemical staining for EP2.
EP2 immunoreactivity was observed in the majority of the cells in the dentate gyrus at P1 and P7, while at P14, it was detected in the outer granule cell layer and was confined to its subgranular zone at P28 and P56. EP2 protein levels in the hippocampal homogenates were also highest at P7 and lowest at P56. EP2 immunoreactivity was partially colocalized, with doublecortin (DCX)-immunoreactive neuroblasts appearing in the mid-zone of the granule cell layer at P14 and in the subgranular zone of the dentate gyrus at P28. Co-localization of EP2 and DCX was significantly decreased in the dentate gyrus in the P28 group compared with that in the P14 group. In COX-2 knockout mice, EP2 immunoreactivity was significantly decreased in the hippocampal CA1 region (=0.000165) and dentate gyrus (=0.00898).
EP2 decreases with age, which is expressed in DCX-immunoreactive neuroblasts in the dentate gyrus. This suggests that EP2 is closely linked to structural lamination and adult neurogenesis in the dentate gyrus.
前列腺素E2 E-前列腺素2受体（PGE2 EP2）位于环氧化酶-2（COX-2）下游，在炎症反应中起重要作用，但关于COX-2和PGE2 EP2在海马体中的突触功能有一些报道。
在出生后第1、7、14、28和56天处死C57BL/6J小鼠，进行EP2和双皮质素的免疫组织化学染色以及EP2的蛋白质印迹分析。此外，对COX-2基因敲除小鼠及其野生型小鼠实施安乐死，进行EP2的免疫组织化学染色。
在出生后第1天和第7天，齿状回中的大多数细胞可观察到EP2免疫反应性，而在出生后第14天，在外颗粒细胞层检测到EP2免疫反应性，在出生后第28天和第56天局限于其颗粒下区。海马匀浆中的EP2蛋白水平在出生后第7天也最高，在出生后第56天最低。EP2免疫反应性部分共定位，双皮质素（DCX）免疫反应性神经母细胞在出生后第14天出现在颗粒细胞层的中间区域，在出生后第28天出现在齿状回的颗粒下区。与出生后第14天组相比，出生后第28天组齿状回中EP2和DCX的共定位显著降低。在COX-2基因敲除小鼠中，海马CA1区（=0.000165）和齿状回（=0.00898）的EP2免疫反应性显著降低。
EP2随年龄增长而减少，在齿状回中表达于DCX免疫反应性神经母细胞。这表明EP2与齿状回的结构分层和成年神经发生密切相关。
