目的 探讨姜黄素预处理对大鼠大脑局灶性缺血再灌注损伤后皮质梗死区线粒体解偶联蛋白2(UCP2)和线粒体转录因子A(TFAM)表达的影响.方法 健康雄性SD大鼠80只,随机均分为假手术组、缺血再灌注(I/R)组、姜黄素高剂量组和低剂量组(简称高、低剂量组).假手术组仅分离暴露右侧颈总、颈外及颈内动脉,其他3组均建立右侧大脑中动脉阻塞模型,缺血2h再灌注24h后处死大鼠,其中高、低剂量组于缺血前5d连续每天分别经腹腔注射姜黄素100、50mg/kg预处理.采用尼氏染色观察大脑中动脉供应皮质区神经元的损伤情况,电镜观察皮质梗死区神经元内线粒体的形态,免疫组化染色和RT-PCR观察UCP2和TFAM在相应皮质区的表达.结果 与假手术组相比,I/R组皮质区神经元水肿,尼氏小体数目减少,神经元内线粒体肿胀,线粒体嵴断裂甚至溶解.缺血前用姜黄素预处理后,神经元丢失及线粒体损伤明显减轻,UCP2和TFAM表达增加(P＜0.05),且以高剂量组增加更明显(P＜0.05).结论 姜黄素可能通过上调UCP2和TFAM的表达来减轻缺血再灌注引起的神经元损伤,调控线粒体生物合成可能成为姜黄素发挥脑保护作用的新靶点.%Objective To investigate the effect of curcumin pretreatment on the expression of uncoupling protein 2 (UCP2) and mitochondrial transcription factor A (MTFA) in rats' cerebral cortex against focal ischemia reperfusion injury. Methods Eighty male SD rats weighed 220g-300g were randomly divided into 4 groups: sham-operated group, ischemia/reperfusion (I/R) group, curcumine 50mg/kg+I/R (low dose) group, and curcumine 100mg/kg+I/R (high dose) group. The common carotid artery, external carotid artery and internal carotid artery on the right side were exposed in the sham-operated group. Animals of the other groups were subjected to a 2-hour period of right middle cerebral artery occlusion, followed by 24 hours of reperfusion, and then they were sacrificed. Curcumin was administered (ip) in a dose of 50mg/kg (low dose group) or 100mg/kg (high dose group) for 5 days, respectively, prior to arterial occlusion. The pathological changes in neurons and their mitochondria in the cerebral cortex supplied by middle cerebral artery were observed with Nissl staining and electron microscope, respectively. The expressions of UCP2 and MTFA in corresponding cotex were assessed by immunohistochemistry and RT-PCR. Results Compared with sham-operated group, animals in I/R group presented edema of neurons in the corresponding cortex, reduction in the number of Nissl bodies, and swelling of mitochondria with broken, even lysis of cristae. Low dose and high dose of curcumin pretreatment before brain ischemia significantly alleviated the loss of neurons and the damage of mitochondria, accompanied with an increase in the expression of UCP2 and TFAM (P<0.05), and the changes appeared a dose-dependent manner (P<0.05). Conclusions Curcumin may prevent neurons from focal cerebral ischemia reperfusion injury by up-regulating UCP2 and MTFA. Regulation of mitochondrial biogenesis may probably be a potential target of curcumin as a neuroprotective drug.
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