丙泊酚对大鼠前脑缺血/再灌注诱导线粒体损伤及解耦联蛋白2表达的影响

目的 探讨丙泊酚对大鼠前脑缺血/再灌注(ischemia reprfnsion,I/R)诱导线粒体损伤及解耦联蛋白2(uncoupling protein 2,UCP 2)表达的影响.方法 45只健康雄性Wistar大鼠,体重250 g～300 g,按随机数字表法分为3组(n=15).采用"二血管阻断法"制备大鼠前脑I/R损伤模型.假手术组(C组):暴露双侧颈总动脉后,侧脑室注射生理盐水1 mg/kg;缺血/再灌注(I/R组):脑缺血后侧脑室注射生理盐水1 mg/kg;丙泊酚干预组(P组):脑缺血后侧脑室注射丙泊酚1 mg/kg.各组分别于再灌注后24 h断头取海马组织,提取海马组织线粒体,加入CaCl2于37℃下孵育5 min.透射电镜下观察线粒体形态学改变(n=3);紫外分光光度计法检测线粒体通透性转换孔(mitochondrial permeability transition pore,MPTP)活性(n=6);Western blotting法检测解耦联蛋白2的表达(n=6).结果 电镜下C组线粒体结构完整,I/R组可见线粒体显著肿胀、嵴断裂、膜破裂,P组损伤程度轻于I/R组.C组、I/R组和P组线粒体吸光度值均下降;与C组相比,I/R组和P组线粒体吸光度值明显下降(p<0.05);与I/R组(0.028±0.007)相比,P组(0.017±0.007)吸光度值下降幅度减小(P<0.05).与C组(0.62±0.05)相比,I/R组(0.88±0.14)和P组(1.32± 0.10)UCP2蛋白表达上调(P<0.05);P组UCP2蛋白表达高于I/R组(P<0.05).结论 丙泊酚能够改善大鼠前脑t/R后线粒体形态,促进神经细胞线粒体UCP2表达上调,抑制线粒体经ca2+诱导后MPTP开放,从而改善线粒体功能,这可能是丙泊酚减轻脑I/R损伤的机制之一.

Effect of propofol on rat forebrain ischemia reperfusion induced mitochondrial damage and uncoupling protein 2 expression

Objective To investigate the effect of propofol on rat forebrain ischemia reperfusion induced mitochondrial damage and uncoupling protein 2 (UCP 2)expression. Methods 45 male Wistar rats weighing 250 g-300 g were randomly divided into three groups (n= 15):control group (C) ;ischemia reperfusion group (I/R) ;propofol group (P). Forebrain cerebral ischemia reperfusion was produced by 2-vessel occlusion method. Bilateral carotid arteries were released after 10 min cerebral ischemia. Normal saline 1 mg/kg and propofol 1 mg/kg were separately injected into the lateral cerebral ventricle by micro syringe in group I/R and group P. The animals were decapitated at the end of 24 h reperfusion and the hippocampal were separated.The mitochondria of hippocampal in each group were isolated. The mitochondria in three groups were incubated by CaCl2for 5 min at 37℃. Morphological changes of mitoehondria were observed by using electron microscopy (n=3). Mitochondrial permeability transition pore (MPTP)opening were detected by ultravioletvisible absorption spectroscopy(n=6). The expression of UCP2 in each group were determined by western blotting method (n=6). Results Group C showed normal mitochondrial ultrastructure;Significant mitochondrial swelling, disrupted cristae and membrane rupture were showed in group I/R;Morphological changes of mitechondria in group P were between group C and group I/R. Absorbance values of mitochondrial decreased in group C, group I/R and group P. Compared with group C, absorbance values of mitochondrial were lower in group I/R and group P (P<0.05). The decrease of absorbance values of mitochondria was reduced in group P(0.017 ± 0.007)compared with that in group I/R (0.028 ± 0.007)(P<0.05). The expression of UCP2 in hippocampus was significantly up-regnlated in group I/R (0.88 ± 0.14) and group P (1.32 + 0. 10)(P<0.05). Compared with group I/R, the expression of UCP2 were higher in group P (P<0.05). Conclusion Propofol improve mitochondrial dysfunction induced by calcium overload after forebrain ischemia reperfusion, indicating by inhibition of MPTP opening and promotion of UCP2 protein expression. This maybe involved in the mechanisms of brain protection of propofol.