龙血素A对大鼠局灶性脑缺血再灌注引起的脑损伤及机制探讨

目的观察龙血素A对急性脑缺血再灌注引起脑水肿的保护作用,初步阐明其作用机制。方法采用线栓法建立右侧大脑中动脉栓塞(MCAO)再灌注模型,分为假手术组、缺血灌注组、龙血素A(30mg·kg-1、60mg·kg-1、120mg·kg-1)组和依达拉奉(3mg·kg-1)组。大鼠再灌注24h后,对其进行神经功能行为学评分,然后断头取脑进行TTC染色计算脑梗死面积,采用干湿重法计算脑含水量,并对脑组织内脂质过氧化产物和抗氧化酶活性进行测定。采用Western blotting对大鼠脑内水通道蛋白-4的表达进行检测,结果与假手术比较,大鼠MCAO2h再灌注24h后,所有动物都出现了神经功能缺损,主要表现为提尾悬空时对侧肩内旋,前肢内收,围绕手术对侧转圈等,模型组最为严重,龙血素A可显著缓解这些神经症状,降低行为学评分。模型组脑组织出现明显的梗塞灶及水肿,MDA含量明显增高,SOD、CAT和GSH-Px活性降低,龙血素A组则具有显著的降低脂质过氧化物、提高抗氧化酶活力,可显著减少梗死面积和脑水肿程度。水通道蛋白-4的表达在模型组缺血侧脑组织出现高表达的现象,龙血素A可显著降低其在缺血侧大脑的表达。结论龙血素A对局灶性脑缺血再灌注引起的损伤具有一定的保护作用,对自由基的清除作用和对水通道蛋白-4表达的抑制作用可能是其作用机制之一。

Effect of Loureirin A on Focal Cerebral Ischemia-Reperfusion Rats and Its Mechanism

Objective Present study is to investigate the effect of luoreirin A (LA )on brains ischemia-reperfusion in rats and to elucidate its mechanism. Methods Two-hour middle cerebral artery occlusion (MCAO)and 24-hour reperfusion surgery was used to establish the cerebral ischemia-reperfusion model. The modeled rats were randomized into sham-operation group, ischemia-reperfusion group, LA groups (in the dose of 30 mg·kg~(-1), 60 mg·kg~(-1) and 120 mg·kg~(-1), respectively), and edaravone (3 mg·kg~(-1))positive control group. After reperfusion for 24 hours, neurobehavioral scores, infracted cerebral area and the percent of water content in the brain were detected for the evaluation of the protection of LA. Lipid peroxidation level, antioxidase activity and the expression of aquaporin protein 4 (AQP4) were also analyzed for the mechanism investigation. Results Ischemia -reperfusion induced the occurrence of neurologic impairment, manifesting as inward rotation of the opposite shoulder, adduction of anterior limbs, circling around the opposite side of the operated part when the rat tail was lifted. LA can relieve the above manifestations and decrease the neurobehavioral scores. Obvious cerebral infarction and edema occurred, MDA content increased, and the activities of SOD, CAT and GSH-Px were decreased, and AQP4 was presented as high expression in the ischemic brain of the modeled rats, and LA counteracted the above changes. Conclusion Luoreirin A exerts certain protection on the injury induced by cerebral ischemia-reperfusion. The scavenge of free radicals and the inhibition of the expression of AQP4 may be one of its mechanisms.