【摘要】 目的观察米诺环素对大鼠脑缺血-再灌注损伤(IRI)后基质金属蛋白酶-9(MMP-9)蛋白的表达及血脑屏障通透性的影响,并探讨其与p38信号通路的关系。方法采用线栓法阻塞大脑中动脉制备大鼠局灶性脑IRI模型,将30只雄性SD大鼠随机分为假手术组、模型对照组及米诺环素组(n=10)。IRI 24 h后,采用伊文思蓝(EB)法测定缺血脑组织血脑屏障通透性的改变,Western blotting法检测MMP-9、claudin-5蛋白表达的变化及p38的磷酸化水平。结果与假手术组比较,模型对照组血脑屏障通透性在IRI 24 h后明显增加[(4.55±0.69)μg·g-1比(0.55±0.08)μg·g-1],MMP-9蛋白表达显著升高(1.18±0.12比0.15±0.02),p38磷酸化水平上升(0.67±0.07比0.11±0.02),claudin-5蛋白表达降低(P<0.05);与模型对照组比较,米诺环素组血脑屏障通透性[(2.82±0.46)μg·g-1比(4.55±0.69)μg·g-1],MMP-9蛋白(0.77±0.06比1.18±0.12)及p38磷酸化水平(0.36±0.04比0.67±0.07)均明显降低,claudin-5蛋白表达显著升高(P<0.05)。结论大鼠局灶性脑IRI后,米诺环素通过调节MMP-9及claudin-5蛋白的表达而减轻血脑屏障破坏,其保护作用可能与抑制p38信号通路有关。更多还原

【Abstract】 Objective To investigate the effects of minocycline on the expression of matrix metalloproteinases-9(MMP-9) and the permeability of blood brain barrier in ischemic cortex of rats after cerebral ischemia reperfusion,and to explore the potential mechanism.Methods Thirty male Sprageue-Dawley rats were randomly divided into 3 groups: sham group,model control group and minocycline group(n = 10 each group).The ischemia / reperfusion injury(IRI) model was induced by ligation with nylon monofilament.At 24 h after IRI,the permeability of blood brain barrier(BBB) in peri-infarct region was evaluated by Evans Blue(EB) test.Expression of MMP-9,claudin-5 and phospholylated p38 mitogen-activated protein kinase(MAPK) were detected by Western blotting.Results Compared to the sham group,the BBB permeability was markedly increased [(4.55 ± 0.69) μg · g-1vs.(0.55 ± 0.08) μg · g-1,P < 0.05],the expression of MMP-9(1.18 ± 0.12 vs.0.15 ± 0.02) and phospholylated p38 protein(0.67 ± 0.07 vs.0.11 ± 0.02) were significantly increased(P < 0.05),and the expression of claudin-5was decreased in the model control group(P < 0.05).Compared to model control group,minocycline significantly alleviated BBB breakdown [(2.82 ± 0.46) μg · g-1vs.(4.55 ± 0.69) μg · g-1],downregulated MMP-9(0.77 ± 0.06 vs.1.18 ± 0.12) and phospholylated p38 protein expression(0.36 ± 0.04 vs.0.67 ± 0.07),promoted claudin-5protein expression(P < 0.05).Conclusion These results indicate that minocycline attenuates BBB disruption after IRI by regulating the expression of MMP-9 and claudin-5 protein,inhibition of p38 pathway may be involved in its neuroprotective effect.更多还原