木犀草苷对缺氧缺血性脑病大鼠脑损伤的影响及机制

Effect and mechanism of luteolin on brain injury in rats with hypoxia-ischemia encephalopathy

目的 探讨木犀草苷对缺氧缺血性脑病(HIE)大鼠脑损伤和Toll样受体4(TLR4)/核因子-κB(NF-κB)信号通路的影响。方法 将60只雄性大鼠随机分为正常对照(NC)组、模型组、低剂量组(25 mg/kg木犀草苷)、高剂量组(50 mg/kg木犀草苷)、高剂量+脂多糖(LPS)组(50 mg/kg木犀草苷+0.5 mg/kg TLR4激动剂LPS),每组12只。用颈总动脉结扎及缺氧手段构建HIE模型。采用神经功能缺损评分(NSS)检测各组大鼠脑部神经功能;ELISA法测量血清肿瘤坏死因子-α(TNF-α)、脑源性神经营养因子(BDNF)水平;HE染色检测脑组织病理变化;试剂盒测定大鼠脑组织丙二醛(MDA)、超氧化物歧化酶(SOD)水平;TTC染色检测大鼠脑梗死情况;Western blot检测脑组织TLR4、核因子-κB(NF-κB)、p-NF-κB、活化的半胱氨酸天冬氨酸蛋白酶3(Cleaved Caspase-3)蛋白表达。结果 与模型组比较,低剂量组、高剂量组大鼠NSS,TNF-α、MDA水平,脑梗死体积及TLR4、p-NF-κB/NF-κB、Cleaved Caspase-3表达降低/减少(P<0.05),BDNF、SOD水平升高(P<0.05),海马区组织病理损伤明显减轻,结构逐渐清晰,神经细胞数量正常;与高剂量组比较,高剂量+LPS组上述指标水平均相反表达(P<0.05),海马区组织病理损伤加重。结论 木犀草苷可改善HIE大鼠脑损伤并抑制TLR4/NF-κB信号通路,且TLR4/NF-κB信号通路的抑制可能是木犀草苷改善脑损伤的作用机制。

Objective To investigate the effects of luteolin on brain injury and Toll like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)signaling pathway in rats with hypoxia-ischemia encephalopathy(HIE).Methods A total of 60 male rats were randomly divided into the normal control(NC)group,the model group,the low-dose group(25 mg/kg luteolin),the high-dose group(50 mg/kg luteolin),and the high-dose+lipopolysaccharide(LPS)group(50 mg/kg luteolin+0.5 mg/kg TLR4 agonist LPS),with 12 rats in each group.HIE model was constructed by ligation of common carotid artery and hypoxia.Neurological severity score(NSS)was used to detect the cerebral nerve function of rats in each group.Serum tumor necrosis factor-α(TNF-α)and brain-derived neurotrophic factor(BDNF)levels were detected by ELISA assay.HE staining was used to detect the pathological changes of brain tissue.The levels of malondialdehyde(MDA)and superoxide dismutase(SOD)in brain tissue of rats were detected by kit.TTC staining was used to detect cerebral infarction in rats.Western blot was used to detect the expression of TLR4,nuclear factor-kappa B(NF-κB),p-NF-κB,activated cleaved cysteine aspartate proteinase 3(Cleaved Caspase-3)protein in brain tissue.Results Compared with the model group,the NSS,levels of TNF-αand MDA,volume of cerebral infarction,and expression of TLR4,p-NF-κB/NF-κB and Cleaved Caspase-3 in low-dose group and high-dose group were decreased(P<0.05),BDNF and SOD levels were increased(P<0.05),the histopathological damage of hippocampus was obviously alleviated,the structure was gradually clear,and the number of nerve cells was normal.Compared with the high-dose group,the levels of the above indexes were inversely expressed in the high-dose+LPS group(P<0.05),and the histopathological damage in the hippocampus was aggravated.Conclusion Luteolin can improve brain injury and inhibit TLR4/NF-κB signaling pathway in HIE rats,and the inhibition of TLR4/NF-κB signaling pathway may be the mechanism of luteolin in improving brain injury.