局部亚低温对大鼠脑出血模型脑组织中紧密连接相关蛋白-5表达的影响

Effect of Local Mild Hypothermia on the Expression of Claudin-5 in Rats after Intracerebral Hemorrhage

目的:探讨局部亚低温对大鼠脑出血(intracerebral hemorrhage,ICH)模型紧密连接相关蛋白-5(Claudin-5)表达的影响以及局部亚低温减轻ICH后水肿的可能机制。方法:选取雄性SD大鼠216只,采用自体血注入法制备ICH模型,并随机分为ICH组和ICH加局部亚低温(ICH+H)组。每组又分为假手术组以及ICH后6 h、12 h、24 h、3 d、7 d组共6个亚组。ICH+H组于注血后给予局部亚低温治疗。采用免疫组织化学法检测Claudin-5的表达,采用伊文思蓝法进行血脑屏障通透性的检测,采用干湿质量法进行脑组织含水量的检测。结果:ICH组大鼠血肿周围脑组织中Claudin-5表达在ICH后6 h开始减少,ICH后24 h下降最显著,ICH后7 d时仍低于假手术组(P<0.05);ICH组大鼠在ICH后6 h开始出现血脑屏障通透性及脑组织含水量增加(P<0.05),在ICH后3 d达到高峰,然后逐渐消退。ICH+H组大鼠ICH后各时间点Claudin-5表达均高于ICH组(P<0.05),而血脑屏障通透性、脑组织含水量则低于ICH组(P<0.05)。结论:局部亚低温可能通过提高Claudin-5的表达来抑制ICH后脑水肿的形成。

Objective：To explore the effect of local mild hypothermia on the expression of Claudin-5 in rat model of intracerebral hemorrhage（ICH）and the possible mechanism of local mild hypothermia in alleviating brain edema after ICH.Methods：A total of 216 male SD rats,in which ICH model were established by injecting autologous blood into caudate nucleus,were randomly divided into the ICH group and ICH＋local mild hypothermia（ICH＋H）group.Each group was further divided into 6subgroups：sham operation subgroup,6 h,12 h,24 h,3 d,7 d after ICH subgroup.In ICH＋H group,the local mild hypothermia was given after the injection of blood.The expression of Claudin-5 in 6 subgroups was detected by immunohistochemical staining repectively.The permeability of blood-brain barrier（BBB）was measured by Evans-Blue extravasation and the brain water content（BWC）was determined by dry-wet weight method.Results：In ICH group,the expression level of Claudin-5 around hematoma decreased gradually from6 h after ICH.It declined most significantly at 24 h after ICH.It was still lower than that in sham operation group at 7 d after ICH（P〈0.05）.The permeability of BBB and BWC increased from 6 h after ICH（P〈0.05）,peaked at 3 d after ICH,and then gradually declined.Compared with that in ICH group,the expression level of Claudin-5 in ICH＋H group were higher,at each time point after ICH,while permeability of BBB and BWC were lower（P〈0.05）.Conclusions：Local mild hypothermia might inhibit the formation of brain edema after ICH by increasing the expression of Claudin-5.