Objective To investigate the effects of morphine preconditioning (MP) on middle cerebral artery occlusion (MCAO) -induced brain injuries and its possible mechanisms. Methods MCAO mouse models were established. The brain infarction sizes and edema ratio were determined by 2,3,5-Triphenyltetrazolium chloride (TTC) , the neurological deficit score was also evaluated. Samples were collected from left cerebral cortex of sham group, ischemic core (I) , penumbra (P) and contralateral cortex (C) from both MCAO and 10 mg/kg MP groups. Western blot analysis was used to determine HSP70 protein expression levels. Western blot analysis was used to determine HSP70 protein expression levels. Results The brain infarct size of MCAO group was 31.69% ±4. 19% , the edema rate was 8.98% ± 1, 79%. MP reduced infarction size and edema ratio significantly compared to MCAO group (P<0.05), there were 23.34% ±4.85% and 4.60% ±0.86% respectively. MP could also improve MCAO-induced neurological deficits score of mice (P <0. 05). Compared with that of sham group, HSP70 expression in mice under MCAO increased significantly (P <0. 05), there was much higher expression of HSP70 in the penumbra of MP group but not in the ischemic core and contraletaral compared with that of MCAO group. Conclusions Morphine preconditioning can attenuate MCAO-induced focal brain ischemic injuries in mice, and the high level of Hsp70 in penumbra may be involved in the neuroprotection.%目的 探讨吗啡预处理(MP)对小鼠大脑中动脉阻塞(MCAO)所致缺血性脑损伤的影响及其可能机制.方法 复制小鼠MCAO模型,用2,3,5-氯化三苯基四氮唑(TTC)染色、神经行为学评分和Western blot等,观察小鼠行为学变化、脑梗死面积、脑水肿率,以及sham组左侧皮质组织,MCAO组和MP组脑梗死核心区、半影区及对侧皮质组织热休克蛋白70( Hsp70)蛋白表达量.结果 MCAO组小鼠脑梗死面积为31.69％±4.19％,脑水肿率为8.98％±1.79％,MP可明显降低MCAO所致的脑梗死面积及水肿率,分别为23.34％±4.85％和4.60％±0.86％(P＜0.05),同时明显改善小鼠神经行为缺陷评分(P＜0.05).MCAO组皮质梗死核心区、半影区及对侧皮质Hsp70蛋白表达水平高于sham组(P＜0.05),MP组半影区Hsp70蛋白表达水平较MCAO组进一步显著升高(P＜0.05).结论 吗啡预处理降低小鼠脑中动脉阻塞所致缺血性脑损伤,半影区Hsp70蛋白水平的高表达可能参与了这种保护作用.
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