亚低温对家兔大脑中动脉梗塞模型脑组织MMP-2与MMP-9表达的影响

The effects of mild hypothermia on the expressions of MMP-2 and MMP-9 in brain tissues of rabbits with middle cerebral artery occlusion

目的探讨脑室内低温对家兔大脑中动脉梗塞模型脑组织基质金属蛋白酶-2(MMP-2)与基质金属蛋白酶-9(MMP-9)表达的影响。方法选用4-6个月龄雄性家兔20只,随机分为对照组(37℃常温生理盐水)和低温组(22℃低温生理盐水),各10只。应用线栓法建立大脑中动脉闭塞(MCAO)模型,进行脑室内穿刺低温液体灌注亚低温干预,24h后,参照ZeaL onga及Bederson检查法进行评分。免疫组织化学方法和Western Blot方法检测各组脑组织MMP-2与MMP-9的表达,伊文思兰染色法测定血-脑屏障通透性的变化。结果兔神经病学体征评分以及动物行为观察发现,低温组评分明显优于常温组;与对照组相比,低温组家兔脑组织的MMP-2与MMP-9的表达水平显著降低(P<0.01)。低温组家兔的血-脑屏障通透性明显低于常温组。结论脑室内穿刺低温干预对急性脑梗塞家兔的脑保护作用可能与下调MMP-2与MMP-9的表达相关。

Objective To explore the effects of mild hypothermia on the expressions of matrix metalloproteinase 2（MMP-2） and matrix metalloproteinase 9（MMP-9） in brain tissues of rabbits with middle cerebral artery occlusion. Methods 20 rabbits were randomly divided into the control group（37℃ normal temperature liquid, n=10） and the mild hypothermia group（22℃ low temperature liquid, n=10） after middle cerebral artery occlusion（MCAO）. The middle cerebral artery occlusion model was made by intralumial thread approach, then we trickled the lateral ventricle continuously with low temperature liquids to the mild hypothermia group and normal temperature liquid to the control group, and the pathological score was determined refer to ZeaLonga and Bederson examination after 24 hours. The expressions of MMP-2 and MMP-9 were detected by immunochemistry and western blot methods, permeability of blood-brain barrier was detected by evans blue staining. Results The pathological score and animal behavior were significantly better in mild hypothermia group than in control group, the expression levels of MMP-2 and MMP-9 in brain tissues were decreased significantly in mild hypothermia group than in control group（P〈0.01）. The permeability of blood-brain barrier of rabbits were decreased obviously in mild hypothermia group than in control group. Conclusion The protection effect of the low temperature treatment on the middle cerebral artery occlusion damage might be related to the downregulation of MMP-2 and MMP-9 exoressions in brain tissue.