Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait.
Physiol Res. 2011;60(6):951-60. doi: 10.33549/physiolres.932167. Epub 2011 Oct 12.
Estrogen replacement therapy could play a role in the reduction of injury associated with cerebral ischemia in vivo, which could be, at least partially, a consequence of estrogen influence of glutamate buffering by astrocytes during hypoxia/ischemia. Estrogen exerts biological effects through interaction with its two receptors: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which are both expressed in astrocytes. This study explored effects of hypoxia and glucose deprivation (HGD), alone or followed by 1 h recovery, on ERα and ERβ expression in primary rat astrocyte cultures following 1 h exposure to: a) 5 % CO(2) in air (control group-CG); b) 2 % O(2)/5 % CO(2) in N(2) with glucose deprivation (HGD group-HGDG); or c) the HGDG protocol followed by 1 h CG protocol (recovery group-RG). ERα mRNA expression decreased in HGDG. At the protein level, full-length ERα (67 kDa) and three ERα-immunoreactive protein bands (63, 60 and 52 kDa) were detected. A significant decrease in the 52 kDa band was seen in HGDG, while a significant decrease in expression of the full length ERα was seen in the RG. ERβ mRNA and protein expression (a 54 kDa single band) did not change. The observed decrease in ERα protein may limit estrogen-mediated signalling in astrocytes during hypoxia and recovery.
雌激素替代疗法可能在体内减少与脑缺血相关的损伤中发挥作用，这至少部分是由于雌激素在缺氧/缺血期间影响星形胶质细胞的谷氨酸缓冲作用所致。雌激素通过与其两种受体（雌激素受体α（ERα）和雌激素受体β（ERβ））相互作用发挥生物学效应，这两种受体均在星形胶质细胞中表达。本研究探讨了单独或在 1 小时 CG 方案后进行 1 小时暴露于以下条件后的 1 小时内缺氧和葡萄糖剥夺（HGD）对原代大鼠星形胶质细胞培养物中 ERα 和 ERβ表达的影响：a）空气 5% CO 2（对照组-CG）；b）N 2 中 2% O 2/5% CO 2 伴葡萄糖剥夺（HGD 组-HGDG）；或 c）HGDG 方案后进行 1 小时 CG 方案（恢复组-RG）。HGDG 中 ERα mRNA 表达减少。在蛋白质水平上，检测到全长 ERα（67 kDa）和三个 ERα-免疫反应性蛋白带（63、60 和 52 kDa）。HGDG 中观察到 52 kDa 带显著减少，而 RG 中全长 ERα 的表达显著减少。ERβ mRNA 和蛋白表达（54 kDa 单带）没有变化。观察到的 ERα 蛋白减少可能会限制缺氧和恢复期间星形胶质细胞中雌激素介导的信号转导。
