糖尿病大鼠缺血再灌注脑组织中MMP-9的表达及其与VEGF的关系

Brain expression of matrix metalloproteinase-9 in focal cerebral ischemia of diabetic rat and its relationship with the vascular endothelial growth factor

目的研究基质金属蛋白酶-9（MMP-9）、血管内皮生长因子（VEGF）在糖尿病缺血再灌注脑组织损伤中的作用。方法120只Wistar大鼠随机分为正常对照组、假手术组、单纯脑梗死组（CI）和糖尿病合并脑梗死组（DM＋CI）。采用高脂高糖饮食加腹腔注射小剂量链脲霉素建立糖尿病大鼠模型，线栓法建立大鼠大脑中动脉缺血再灌注模型，免疫组化法检测脑组织中MMP-9、VEGF表达。结果MMP-9和VEGF阳性表达主要分布于梗死灶周围半暗带胶质细胞、神经细胞、血管内皮细胞等处；CI组和DM＋CI组大鼠脑组织中MMP-9的表达均较正常对照组明显增加（P〈0．05），DM＋CI组较CI组明显增加（P〈0．05）；DM＋CI组MMP-9于再灌注3h开始升高，24h达到高峰，7d后逐渐下降；DM＋CI组和CI组大鼠脑组织中VEGF的表达均较正常对照组明显增加（P〈0．01），DM＋CI组较CI组明显减少（P〈0．01）；DM＋CI组VEGF于再灌注1h开始升高，6h达到高峰，随后逐渐降低。DM＋CI组和CI组大鼠脑组织中MMP-9与VEGF的表达呈直线相关，其中DM＋CI组于再灌注6～24h时段MMP-9与VEGF表达呈负相关。结论糖尿病缺血再灌注大鼠脑组织中MMP-9的表达增加与VEGF的下调相关，参与糖尿病合并脑梗死的病理生理过程。

Objective To investigate the involvement of matrix metalloproteinase-9 and the vascular endothelial growth factor in diabetic rat brains during different reperfusion times after focal cerebral ischemia. Methods 120 Wistar rats were randomly divided into 4 groups： the normal control group, the operation control group, the simple cerebral ischemic rats（CI group） and the diabetic cerebral ischemic rats（DM ＋ CI group）. Rat models of diabetes mellitus were made by high sucrose, fat diet and streptozotion injection. The models of the middle cerebral artery occlusion were made by an improved zealong＇s method. The expressions of MMP-9 and VEGF in the brain tissues were determined by immunohistochemistry staining. Results MMP-9 and VEGF mainly distributed in the cytoplasm of neurogha cells, neurons, some vascular endothehal cells, and in the ischemic penumbra zones of the DM ＋ CI group and the CI group. Along with the reperfusion times, the expressions of the cells changed differently. MMP-9 and VEGF significantly increased in the DM ＋ CI group and the CI group compared with the normal control group （ P 〈 0.05）.MMP-9 was more significantly increased in the DM ＋ CI group than in the CI group （ P 〈 0.05） and peaked at 24 h; VEGF was more significantly decreased in the DM ＋ CI group than in the CI group （ P 〈 0.01 ） and peaked at 6 h. There was a hnear correlation between MMP-9 and VEGF expressions in the DM ＋ CI group and the CI group. In the DM ＋ CI group, MMP-9 and VEGF expressions were negatively correlated at 6-24 h after reperfusion. Conclusions The increase of MMP-9 expression contributes to the decrease of VEGF and it may participate in the pathology of reperfusion of diabetic infarct brains.