绿茶多酚通过抑制TLR4通路减轻蛛网膜下腔出血大鼠早期脑损伤

Green tea polyphenols alleviate early brain injury in rats with subarachnoid hemorrhage by inhibiting TLR4 pathway

目的探讨绿茶多酚通过抑制TLR4通路对蛛网膜下腔出血大鼠早期脑损伤的影响。方法建立大鼠蛛网膜下腔出血模型,随机分为模型组、绿茶多酚组、TAK-242(TLR4抑制剂)组、绿茶多酚+TAK-242组,每组12只;另取12只大鼠设为假手术组。药物处理后,对所有大鼠进行神经功能缺损评分,检测各组大鼠脑组织含水量,采用Evans蓝外渗实验评定血脑屏障通透性,采用苏木精-伊红(HE)染色检测各组大鼠脑皮层神经元受损情况,采用酶联免疫吸附法(ELISA)检测血清中白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平,采用蛋白免疫印迹法检测脑组织中TLR4通路蛋白TLR4、MyD88、NF-κB p65表达情况。结果与假手术组相比,模型组大鼠皮层结构紊乱疏松,神经元出现变性、坏死,数目减少,细胞核固缩、深染等病理改变,脑组织及神经元受损,神经功能缺损评分、脑组织含水量、Evans蓝渗出量、血清中IL-6及TNF-α水平、脑组织TLR4、MyD88及NF-κB p65蛋白表达均明显升高(P<0.05);与模型组相比,绿茶多酚组、TAK-242组、绿茶多酚+TAK-242组大鼠脑皮层神经元损伤减轻,神经功能缺损评分、脑组织含水量、Evans蓝渗出量、血清中IL-6及TNF-α水平、脑组织TLR4、MyD88及NF-κB p65蛋白表达均降低(P<0.05);与绿茶多酚组及TAK-242组分别相比,绿茶多酚+TAK-242组大鼠脑组织及神经元病理损伤进一步减轻,神经功能缺损评分、脑组织含水量、Evans蓝渗出量、血清中IL-6及TNF-α水平、脑组织TLR4、MyD88及NF-κB p65蛋白表达均降低(P<0.05)。结论绿茶多酚可通过抑制TLR4通路减轻蛛网膜下腔出血大鼠早期脑损伤。

To investigate the effect of green tea polyphenols on early brain injury in rats with subarachnoid hemorrhage by inhibiting TLR4 pathway,rat subarachnoid hemorrhage model was established and randomly divided into model group,green tea polyphenols group,TAK-242(TLR4 inhibitor)group and green tea polyphenols+TAK242 group,with 12 rats in each group,and another 12 rats were divided into sham operation group.After drug treatment,all rats were scored for neurological deficit,and water content of brain tissue was measured,blood-brain barrier permeability was evaluated by Evans blue extravasation test,neuronal damage in cerebral cortex was detected by hematoxylin-eosin(HE)staining,the levels of interleukin-6(IL-6)and tumor necrosis factor-α(TNFα)in serum were detected by enzyme-linked immunosorbent assay(ELISA),the expressions of TLR4 pathway protein TLR4,MyD88 and NF-κB p65 in brain tissue were detected by Western blotting.Compared with shamoperated group,the cortical structure of rats in model group were disordered and loosened,the neurons degenerated and necrotized,the number of neurons decreased,the pathological changes such as nuclear pyknosis and deep staining appeared,the brain tissue and neurons damaged,while the neurological deficit score,the water content of brain tissue,Evans blue exudation,the serum IL-6 and TNF-αlevels,MyD88 and NF-κB p65 protein expressions in brain tissue were significantly increased(P<0.05).Compared with the model group,the injury of cortical neurons in green tea polyphenols group,TAK-242 group,green tea polyphenols+TAK-242 group was alleviated,and the neurological deficit score,water content of brain tissue,Evans blue exudation,serum IL-6 and TNF-αlevels,MyD88 and NF-κB p65 protein expressions in brain tissue were all decreased(P<0.05).Compared with the green tea polyphenols group and TAK-242 group,the pathological damage of brain tissue and neurons in the green tea polyphenols+TAK-242 group was further alleviated,the neurological deficit score,water content of brain tissue,Evans blue exudation,serum IL-6 and TNFαlevels,MyD88 and NF-κB p65 protein expressions in brain tissue were all decreased(P<0.05).Taken together,green tea polyphenols can alleviate early brain injury in rats with subarachnoid hemorrhage by inhibiting TLR4 pathway.