Motaghi Sahel, Sayyah Mohammad, Babapour Vahab, Mahdian Reza
Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran.
Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Iran Biomed J. 2017 May;21(3):167-73. doi: 10.18869/acadpub.ibj.21.3.167. Epub 2017 Apr 23.
Gap junctions (GJs) provide direct intercellular communications that are formed by hexameric protein subunits, called connexin (Cx). The role of Cxs in epileptogenesis has not received sufficient attention. Hippocampus with critical function in epileptogenesis has a wide network of GJs. We examined the protein expression levels of hippocampal Cx36 (the prominent Cx present between GABAergic interneurons) and Cx43 (the main Cx expressed by astrocytes) during epileptogenesis in the pilocarpine model of epilepsy.
Male Wistar rats received scopolamine (1 mg/kg, s.c.). Pilocarpine (380 mg/kg, i.p.) was administered 30 min thereafter to induce status epilepticus (SE). SE was stopped 2 h later by diazepam (10 mg/kg, i.p.). Cx36 and Cx43 protein expression was assessed by Western blot analysis in the hippocampus of SE-experienced rats, after injection of diazepam (F0 subgroup), after acquisition of focal seizures (F3 subgroup), and after development of generalized seizures (F5 subgroup). The control subgroups, C0, C3, and C5, were aged-matched rats, which received saline (1 ml/kg, i.p.) instead of pilocarpine. Injection of scopolamine and diazepam, and dissection of hippocampi were carried out at the same time interval as the test subgroups.
SE emerged in 67.1% of pilocarpine-treated animals. Focal and generalized seizures developed 3.8±0.4 and 7.0±0.5 days after SE, respectively. Cx36 protein abundance was not significantly different between test and control groups in the three time points. However, Cx43 protein level showed 40% increase in F3 subgroup (P<0.05 compared to C3, P<0.01 compared to F0 and F5).
Hippocampal Cx43 is overexpressed in pilocarpine model of epileptogenesis after acquisition of focal seizures.
间隙连接（GJs）提供直接的细胞间通讯，由六聚体蛋白亚基连接蛋白（Cx）形成。连接蛋白在癫痫发生中的作用尚未得到充分关注。在癫痫发生中起关键作用的海马具有广泛的间隙连接网络。我们在匹罗卡品癫痫模型的癫痫发生过程中，检测了海马中Cx36（GABA能中间神经元之间存在的主要连接蛋白）和Cx43（星形胶质细胞表达的主要连接蛋白）的蛋白表达水平。
雄性Wistar大鼠皮下注射东莨菪碱（1 mg/kg）。30分钟后腹腔注射匹罗卡品（380 mg/kg）以诱导癫痫持续状态（SE）。2小时后用地西泮（10 mg/kg，腹腔注射）终止SE。在注射地西泮后（F0亚组）、出现局灶性癫痫发作后（F3亚组）和出现全身性癫痫发作后（F5亚组），通过蛋白质印迹分析评估经历SE的大鼠海马中Cx36和Cx43蛋白表达。对照亚组C0、C3和C5为年龄匹配的大鼠，它们接受生理盐水（1 ml/kg，腹腔注射）而非匹罗卡品。东莨菪碱和地西泮的注射以及海马的解剖与测试亚组在相同的时间间隔进行。
67.1%的匹罗卡品处理动物出现SE。局灶性和全身性癫痫发作分别在SE后3.8±0.4天和7.0±0.5天出现。在三个时间点，测试组和对照组之间Cx36蛋白丰度无显著差异。然而，Cx43蛋白水平在F3亚组中增加了40%（与C3相比，P<0.05；与F0和F5相比，P<0.01）。
在匹罗卡品癫痫发生模型中，出现局灶性癫痫发作后海马Cx43过度表达。
