Shh信号通路对脑梗死大鼠BCFB的影响及机制研究

Effect and mechanism of Shh signaling pathway on blood-cerebrospinal fluid barrier in cerebral infarction in rats

目的 探讨大鼠脑梗死后Sonic Hedgehog (Shh)信号通路对血-脑脊液屏障(bloodcerebrospinal fluid barrier,BCFB)的影响及可能机制。方法 采用线栓法建立大鼠永久性大脑中动脉闭塞模型。Sprague-Dawley (SD)大鼠随机分为3组:假手术组、溶剂对照组和特异性阻断剂环巴胺组(10mg·kg^(-1))。术后24h分别采用免疫组织化学方法、Western blot及RT-PCR观察缺血周围区glioma-associated oncogene homolog 1 (Gli1)和Claudin-5的表达水平,干湿重法测定脑组织含水量,TTC染色法测定脑梗死范围,评估损伤程度。结果 免疫组织化学、Western blot及RT-PCR显示脑缺血24 h后与Vehicle组比较,环巴胺组脑梗死大鼠大脑皮质的Gli1和Claudin-5表达水平下降,脑含水量增加,脑梗死范围增大。结论 抑制Shh信号通路加重了BCFB完整性的破坏。Shh信号通路在BCFB结构水平上对脑组织有保护作用,该机制可能是通过调节Claudin-5的表达水平来完成。

Objective In this study,the effect of Shh signaling pathway on blood-cerebrospinal fluid barrier(BCFB) and its possible mechanism after cerebral infarction in rats were investigated.Methods The permanent model of middle cerebral artery occlusion(MCAO) in rats was established by suture plug method.Sprague-Dawley(SD) rats were randomly divided into 3 groups:sham operation group,vehicle group and inhibitor cyclopamine group(10 mg·kg^(-1)).The expressions of glioma-associated oncogene homolog 1(Gli1) and claudin-5 in the ischemic peripheral area were observed by immunohistochemical,Western blot and RT-PCR at 24 h after surgery.The moisture content of brain tissue was measured by wet and dry weight method,and triphenyltetrazole chloride(TTC) staining was used to determine the extent of cerebral infarction to evaluate the degree of injury.Results Immunohistochemistry,Western blot and RT-PCR showed that compared with the Vehicle group,the expression levels of Glil and Claudin-5 in cerebral cortex of the inhibitor group were decreased,and brain water content was increased.Conclusion Inhibition of Shh signaling pathway exacerbates the damage of BCFB integrity.Shh signaling pathway has a protective effect on brain tissue at the level of BCFB structure,which may be accomplished by regulating the expression level of Claudin-5.