阿司匹林对大鼠局灶脑缺血后基质金属蛋白酶-3及骨桥蛋白表达的影响

目的观察大鼠脑缺血/再灌注(CI/RP)后基质金属蛋白酶-3(MMP-3)和骨桥蛋白(OPN)表达的规律以及阿司匹林对其表达的影响。方法健康雄性SD大鼠75只,随机分为假手术组(n=15)、阿司匹林组(n=30,再灌注后即刻及每日清晨腹腔注射阿司匹林80 mg·kg-1,溶于10%L-赖氨酸等渗盐水1.5 mL)和对照组(n=30,相同时间点注射10%L-赖氨酸1.5 mL)。采用线栓法制作大脑中动脉阻塞模型(缺血2 h);每组按再灌注时间6 h、24 h、3 d、5 d、7 d分5个亚组。采用免疫组化方法检测MMP-3和OPN蛋白表达。结果 CI/RP后神经元、小胶质细胞、小血管以及脉络丛均见MMP-3表达:①CI/RP后6 h,MMP-3表达开始在梗死区出现,1~3 d最明显,7 d仍有表达;②CI/RP后3 d,梗死周边区小胶质细胞MMP-3表达开始出现,7 d最多;③阿司匹林干预后,梗死周边区MMP-3表达明显减少,3~7 d最为显著(P0.05)。OPN主要在小胶质细胞表达:①CI/RP后6 h,OPN阳性小胶质细胞局限在梗死周边区,24 h达高峰,持续至7 d;②24 h梗死中心区开始出现OPN阳性小胶质细胞,7 d时达高峰;③阿司匹林干预后,OPN阳性小胶质细胞数较对照组略有减少,但差异无统计学意义(P0.05);而OPN阳性小胶质细胞与小胶质细胞总数的比率明显增高(P0.01)。结论 CI/RP后缺血神经元MMP-3表达增加,小胶质细胞OPN表达上调;CI/RP后阿司匹林通过抑制MMP-3表达和进一步上调OPN表达而发挥神经保护作用。

Effects of Aspirin on Matrix Metalloproteinase-3 and Osteopontin Expression after Transient Focal Cerebral Ischemia of Rats

Aim To observe the expressions of matrix metalloproteinase-3 （MMP-3） and osteopontin （OPN） after focal cerebral ischemiaJreperfusion （CI/RP） in rats and the effect of aspirin on their expressions. Methods A total of 75 healthy male Sprague-Dawley rats were randomly assigned to a sham group, a control group and a aspirin group. Each group was further divided into five subgroups according to the reperfusion time of 6 h, 24 h, 3 d, 5 d and 7 d after vessel occlusion. A model of temporary middle cerebral artery occlusion （2 h） was established by suture method. Aspirin （80 mg.kg1 dissolved in 1.5 mL 10% L-lysine normal saline solution） was intraperitoneally injected immediately after reperfusion and once every early morning in aspirin group, and instead of 1.5 mL 10% L-Lysine in the control group. The expressions of MMP-3 and OPN of ischemic brain tissues were detected by immunohistochemistry. Results MMP-3 expression was mainly found in neurons, microglia, small vessels and choroid plexus. In the infarct region, the MMP-3 expressing neurons were occurred 6 hours after CI/RP, increased significantly from day 1 to day 3, and still existed at day 7. The MMP-3 expressing microglia appeared in the peri-infarct areas at day 3, and reached to maximum at day 7. Aspirin could decrease the number of MMP-3 expressing neurons in the peri-infarct areas significantly, and reached the most significant from day 3 to day 7 （P〈 0.05）. The OPN was mainly expressed in microglia. In the peri-infarct areas the numbers of OPN expressing cells were increased 6 hours after reperfusion, reached to maximum at 24 h, and still expressed at day 7. In the infarct core the numbers of OPN positive microglia were appeared at 24 h, and reached to maximum at day 7. After the intervention of aspirin, the number of OPN positive cells decreased insignificantly compared with the control group （P〉0.05）. However, the percentage rate of OPN positive cells increased significantly （P〈0.01）. Conclusion The number of MMP-3 positive neurons and the percentage rate of OPN positive microglia increased after CI/RP. Aspirin might inhibit MMP-3 expression of neurons and enhance OPN expression of microglia, which plays a role of protecting neurons.