依达拉奉通过下调p38丝裂原活化蛋白激酶和水通道蛋4表达减轻局灶性脑缺血再灌注小鼠脑水肿和脑损伤

Edaravone attenuates brain edema and injury by down-regulating expressions of p38 mitogen-aclivated protein ldnase and aquaporin-4 after focal cerebral ischemia and reperfusion in mice

目的探讨依达拉奉对缺血再灌注小鼠脑组织p38丝裂原活化蛋白激酶（mitogen-activated protein kinase，MAPI（）和水通道蛋4（aquaporin4，AQP4）的影响和神经保护作用。方法196只健康雄性昆明小鼠随机分为假手术组、缺血再灌注组、生理盐水对照组和依达拉奉组，每组49只。采用大脑中动脉闭塞法（middle cerebral artery occlusion，MCAO）建立脑缺血再灌注模型。依达拉奉组和生理盐水对照组在缺血2h后再灌注即刻分别腹腔注射依达拉奉（5mg／kg）和同体积生理盐水，然后每隔24h重复1次。在MCAO2h后再灌注不同时间点（12h、24h、48h和3d）分别进行脑含水量和脑梗死体积检测。MCAO后24h，采用蛋白质印迹法检测缺血周围皮质脑组织AeQ4和p38MAPK表达。结果依达拉奉组不同时间点梗死体积（P均〈0．01）和脑含水量（P均〈0．05）均较缺血再灌注组和生理盐水对照组缩小和降低，以48h时最为显著。再灌注24h后，缺血再灌注组、生理盐水对照组和依达拉奉组缺血周围皮质脑组织AQP4（0．985±0．129、1．024±0．117、0．713±0．231）和磷酸化p38MAPK（1．123±0．142、1．214±0．096、0．986±0．087）表达均较假手术组（AQP4：0．265±0．123；磷酸化p38MAPK：0．465±0．023）显著上调（P均〈0．01），但依达拉奉组显著低于缺血再灌注组和生理盐水对照组（P均〈0．05）。结论依达拉奉能下调APQ4表达水平，有效保护小鼠脑缺血再灌注损伤，其机制可能与抑制p38MAPK通路有关。

Objective To investigate the effects on brain tissue p38 mitogen-activated protein kinase （MAPK） and aquaporin 4 （AQP4） and neuroprotective effect of edarvone after focal cerebral ischemia and reperfusion in mice.Methods A total of 196 healthy male Kunming mice were randomly divided into four groups： a sham operation group, an ischemia-reperfusion group, a saline control group, and an edaravone group （n =49 in each group）. A middle cerebral artery occlusion （MCAO） mothod was used to induce a cerebral isehemia-reperfusion model. At 2 h after ischemia, immediately after reperfusion in the edaravone group and the saline control group, edaravone （5 mg/kg） and the same volume of saline were injected intraperitoneaUy in mice, then repeated once every 24 h. At 2 h after MCAO, the brain water content and infarct volume at different time points after reperfusion （12 h, 24 h, 48 h, and 3 d） were measured respectively. At 24 h after MCAO, the expressions of AQP4 and p38 MAPK in the brain tissue of ischemic peripheral cortex were measured by Western blotting. Results The volumes of cerebral infarction （all P 〈 0. 01） and the brain water contents （all P 〈0. 05） in the edaravone group were decreased than those in the ischemia-reperfusion group and saline control group at different time points, and they were most significant at 48 h. After 24-h reperfusion, the expression levels of AQP4 （0. 985 ± 0. 129, 1. 024 ± 0. 117, 0. 713 ± 0. 231） and phospho-p38 MAPK （1. 123 ± 0. 142, 1. 214 ± 0. 096, 0. 986 ± 0. 087） in the brain tissue of ischemic peripheral cortex in the ischemia-reperfusion group, the saline control group, and the edaravone group were upreguiated significantly than those in the sham operation gronp （AQP4： 0. 265 ± 0. 123; phospho-p38 MAPK： 0. 465 ±0. 023; all P 〈0. 01）, but edaravone group were significantly lower than the ischemia-reperfusion group and the saline control group （all P 〈 0.05）. Conclusions Edaravone can downregulate the expression level of AQP4 and effectively protect cerebral ischemia reperfusion injury in mice, Its mechanism may be associated with the inhNition of p38 MAPK pathway.