葛根素预处理对大鼠局灶性脑缺血再灌注损伤的保护作用及机制

目的探讨葛根素预处理对局灶性脑缺血再灌注损伤的保护作用及其可能机制。方法健康成年雄性SD大鼠120只，随机分成5组（n=24）：假手术组（S组），脑缺血再灌注组（IR组），Pc-24h100mg组，Pc-24h200mg组，Pc-24h400mg组，其中Pc-24h组于脑缺血前24h给予相应剂量葛根素腹腔注射行单次预处理，采用大脑中动脉线栓法建立局灶性脑缺血再灌注模型，缺血90min，再灌注24h。大鼠清醒后进行神经功能缺陷评分，再灌注24h时处死大鼠，处死后取脑组织，测定脑梗死容积比（BIVP）、脑组织含水量及MDA水平。结果葛根素预处理可以改善大鼠脑缺血再灌注损伤的神经功能缺损评分，降低BIVP、脑组织含水量及MDA水平（P均〈20.01）。其中Pc-24h400mg组减低神经功能缺损评分、BIVP及脑组织含水量明显优于Pc=24h100mg及Pc-24h200mg组（P均〈0.01），而Pc-24h100mg及Pc-24h200mg组之间无显著差异（P均〉0.05）。结论葛根素预处理可能通过抑制脑水肿及氧化损伤来减轻大鼠局灶性脑缺血再灌注损伤。葛根素预处理的脑保护作用具有一定的量效关系。

Protective effects and related mechanisms of puerarin preconditioning on focal cerebral ischemia-reperfusion injury in rats

Objective To study the protective effects and probable mechanisms of puerarin preconditioning （PC） on focal cerebral ischemia-reperfusion（IR） injury. Methods One hundred and twenty male Sprague- Dawley rats were randomly divided into 5 groups（n = 24） .sham operation group（group S）, IR group, PC-24 h 100 mg group, PC-24 h 200mg group and PC-24 h 400mg group with 24 rats each. Puerarin 100 mg·kg-1 ,200 mg.kg-1 and 400 mg·kg-1 were injected intraperitoneal 24 h before cerebral ischemia in PC-24 h groups, respectively. Focal cerebral ischemia reperfusion mode was induced by occlusion of middle cerebral artery for 90 rain followed by 24 h of reperfusion. The neurological deficit score was measured at 24 h after IR. The brain infarct volume percentage（BIVP） was then assessed after 2~TTC staining following the last neurological out-come evaluation. The brain tissues were taken for determination of the brain water content as well as the measurement of MDA. Results PC at different dosages（100,200,400 mg.·kg-1 ） could obviously decrease neurological deficit score, reduce the BIVP, MI）A and brain water content in rats of cerebral IR （P〈0.01）. The neuro- logical deficit score , BIVP and brain water content in PC-24 h 400 mg group was significantly lower than those in the PC-24 h 100 mg group and PC-24 h 200rag group （P〈0. 01） , but there was no significant difference between the PC-24 h 100mg group and the PC-24 h 200 mg group （P〉0. 05）. Conclusions Puerarin preconditioning can relieve focal cerebral IR injury. The protective mechanism might be related to the effect of reducing brain edema and scavenging oxidative damage. The neuroprotective effect of puerarin preconditioning is related to its dosage.