后适应对大鼠实验性局灶性脑缺血/再灌注损伤的保护作用

Effect of ischemic postconditioning on focal cerebral ischemia reperfusion injury in rats

目的研究后适应对大鼠局灶性脑缺血/再灌注损伤的保护作用与氧自由基的关系。方法大脑中动脉线拴法(MCAO)制作大鼠局灶性脑缺血/再灌注模型:50只♂性SD大鼠随机分为假手术组(sham)、脑缺血/再灌注模型组(MCAO)、预适应组(MCAO+preconditioning)、后适应组(MCAO+postconditioning)和尼莫地平组(MCAO+nimodip-ine),每组10只大鼠。术后对大鼠进行神经缺陷评分,并取脑组织测量梗死体积。另取50只大鼠,分组、实验方法及步骤同上,术后取梗死侧脑组织做成匀浆,检测脑组织中丙二醛(MDA)、乳酸(LA)、超氧化物歧化酶(SOD)和谷胱甘肽(GSH)含量。结果后适应能减少大鼠实验性局灶性脑缺血的梗死体积、降低脑含水量,改善其神经行为。脑组织匀浆生化指标检测发现缺血后适应能降低脑组织中MDA和LA含量;升高SOD和GSH含量,与MCAO模型组比较,差异有显著性(P<0.05)。结论缺血后适应能诱导脑缺血耐受,对脑缺血/再灌注损伤产生保护作用,其保护作用与增加脑组织的抗氧化能力有关。

Aim To investigate whether ischemic postconditioning could induce ischemic tolerance to focal cerebral reperfusion injury and comparison with ischemic preconditioning. Methods A reversible middle cerebral artery occlusion （MCAO）was used in this study. Fifty male Sprague-dawley rats were randomized into five groups（ n = 10） ： sham-operated group, MCAO group, preconditioning group, postconditioning group and nimodipin group . The neurological function was scored and the infarct volume was measured after operation. The grouping, experimental methods and procedures of another fifty rats were as above except that ipsilateral brain of infarction was dissected and made into homogenate, then the contents of MDA, SOD, GSH and LA were quantitatively measured. Results The postconditioning and preconditioning improved the neurological function, reduced the cerebral infarction volumes and cerebral swelling significantly compared with those of the MCAO group. Contents of LA and MDA were lower, while the activity of SOD in the brain tissues were higher in preconditioning group and postconditioning group than those of the MCAO group. Conclusion Postconditioning could induce brain tolerance, and increase the antioxidant activity, which might be an important mechanism of induction of brain tolerance.