不同剂量尿激酶对大鼠脑出血后血脑屏障作用的研究

Protective Effects of Different Doses of Urokinase on Blood-Brain Barrier in Rat Model of In⁃tracerebral Hemorrhage

目的:比较不同剂量尿激酶对大鼠脑出血(ICH)后血脑屏障(BBB)的影响及机制。方法:成年雄性Wistar大鼠40只,经尾状核注射自体血建立ICH模型,造模成功后,40只大鼠随机分为ICH组和低(3万U/mL)、中(5万U/mL)、高剂量(10万U/mL)尿激酶组(L、M、H组),每组10只。造模成功3 h后,将不同剂量的尿激酶分别注入血肿处,模型对照组给予等量生理盐水。造模后3 d,采用干湿重法检测血肿周围脑组织含水量,伊文斯蓝染色检测BBB渗透性,Western blot检测血肿周围脑组织紧密连接蛋白(ZO-1)和基质金属蛋白酶9(MMP-9)的表达变化。结果:与ICH组比较,L、M和H组大鼠血肿周围脑组织含水量降低(均P<0.05),大鼠脑组织的EB染料血管外渗出减少(均P<0.05),脑组织ZO-1表达明显升高(均P<0.05),MMP-9的表达明显降低(均P<0.05);且L组(300 U尿激酶)的血肿周围脑组织含水量最低,EB染料血管外渗出最少,脑组织ZO-1表达最高,MMP-9的表达最低,与M和H组差异均有统计学意义(均P<0.05)。结论:300 U尿激酶血肿腔内注射治疗能保护ICH后BBB的完整性,其机制可能与ZO-1表达增加及MMP-9表达降低有关。

Objective:To compare the effects and mechanism of different doses of urokinase on the blood-brain barrier(BBB)in rats of intracerebral hemorrhage(ICH).Methods:We selected 40 adult male Wistar rats and es-tablished the ICH model by autologous blood injection into the caudatum.After successful modeling,they were randomly divided into 4 groups,each with 10 rats:the control group and the low dose(30000 U/mL),medium dose(50000 U/mL),and high dose(100000 U/mL)urokinase groups,respectively named the ICH group and L,M,and H dose groups.Three hours after establishment of the model,different doses of urokinase were injected into the hematoma respectively,and the rats in the ICH group received the same amount of normal saline.Three days after modeling,the brain water content was measured by the dry/wet weight method,the BBB permeability was evaluated by Evans blue fluorescence,and the expression levels of zonula occludens-1(ZO-1)and matrix metallo-proteinase9(MMP-9)in brain tissues around the hematoma were detected by Western blot.Results:Compared with the ICH group,the L,M,and H dose groups showed a decreased water content in brain tissues surrounding the hematoma(all P<0.05),reduced EB dye permeation out of blood vessels in brain tissues(all P<0.05),and up-regulated ZO-1(all P<0.05)and down-regulated MMP-9(all P<0.05)in brain tissues.Furthermore,the L dose group exhibited the lowest water content in tissues surrounding the hematoma,the least EB dye seepage from blood vessels,the highest ZO-1 expression,and the lowest MMP-9 expression,with results being significantly dif-ferent from those of the M and H dose groups(all P<0.05).Conclusion:The injection of 300 U urokinase into he-matoma serves to protect the integrity of the BBB after ICH,and the mechanism may involve increasing ZO-1 and decreasing MMP-9 expression.