槲皮素调控TLR4/NF-κB通路对阿尔茨海默病大鼠认知功能障碍及海马神经元损伤的影响

Influences of Quercetin on Cognitive Dysfunction and Hippocampal Neuronal Damage in Rats with Alzheimer's Disease Through Modulation of TLR4/NF-κB Pathway

目的:探讨槲皮素(Que)调控Toll样受体4(TLR4)/核因子-κB(NF-κB)通路对阿尔茨海默病(AD)大鼠认知功能障碍及海马神经元损伤的影响。方法:将60只大鼠随机分为假手术组(10只)及造模组(50只),造模组通过脑内注射Aβ_(1~42)构建AD大鼠模型,将造模成功大鼠随机分为AD组、Que低剂量组(Que-L,50 mg/kg)、Que中剂量组(Que-M,100 mg/kg)、Que高剂量组(Que-H,200 mg/kg)、Que-H+LPS(TLR4激活剂)组(200 mg/kg Que+0.1 mg/kg LPS),每组10只。干预结束后,Morris水迷宫实验检测大鼠空间学习记忆能力;ELISA检测血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)水平;HE染色观察大鼠海马组织病理变化;TUNEL染色检测细胞凋亡变化;Western blotting检测海马组织中TLR4、p-NF-κB p65/NF-κB p65表达水平。结果:AD组大鼠穿越平台次数少于假手术组,逃避潜伏期、血清TNF-α、血清IL-1β、细胞凋亡率、TLR4蛋白相对表达量及p-NF-κB p65/NF-κB p65均高于假手术组,差异均有统计学意义(P<0.05);Que-L组、Que-M组、Que-H组穿越平台次数均多于AD组,逃避潜伏期、血清TNF-α、血清IL-1β、细胞凋亡率、TLR4蛋白相对表达量及p-NF-κB p65/NF-κB p65均低于AD组,差异均有统计学意义(P<0.05),且呈现剂量依赖性;Que-H+LPS组大鼠穿越平台次数少于Que-H组,逃避潜伏期、血清TNF-α、血清IL-1β、细胞凋亡率、TLR4蛋白相对表达量及p-NF-κB p65/NF-κB p65均高于Que-H组,差异均有统计学意义(P<0.05)。结论:Que可以改善AD大鼠认知功能障碍及海马神经元损伤,可能与抑制TLR4/NF-κB通路有关。

Objective:To investigate the influences of quercetin(Que)on cognitive dysfunction and hippocampal neuronal damage in Alzheimer's disease(AD)rats by modulating Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB)pathway.Methods:Totally 60 rats were randomly divided into sham-operation group(n=10)and modeling group(n=50).The modeling group was constructed by intracerebral injection of Aβ_(1-42) for AD rat model,and the successfully modeled rats were randomly grouped into AD group,Que low(Que-L,50 mg/kg)dose group,Que medium(Que-M,100 mg/kg)dose group,Que high dose(Que-H,200 mg/kg)groups and Que-H+LPS(TLR4 activator)group(200 mg/kg Que+0.1 mg/kg LPS),10 rats in each group.After the end of the intervention,Morris water maze experiment was applied to detect spatial learning memory ability in rats.ELISA was applied to detect serum levels of tumor necrosis factor-α(TNF-α)and interleukin(IL)-1β.HE staining was applied to observe histopathological changes in rat hippocampus.TUNEL staining was applied to detect apoptotic changes.Western blotting was used to detect the expression levels of TLR4 and p-NF-κB p65/NF-κB p65 in hippocampal tissues.Results:The AD group showed lower number of crossing the original platform than sham-operated group,while higher escape latency,serum TNF-α,serum IL-1β,apoptosis rate,TLR4 expression,and p-NF-κB p65/NF-κB p65 than sham-operated group,with statistically significant differences(P<0.05).The Que-L,Que-M and Que-H groups showed higher number of crossing the original platform than AD group,while lower escape latency,serum TNF-α,serum IL-1β,apoptosis rate,TLR4 expression,and p-NF-κB p65/NF-κB p65 than AD group,with statistically significant differences(P<0.05).And there was a dose-dependence.The Que-H+LPS group showed lower number of crossing the original platform than Que-H group,while higher escape latency,serum TNF-α,serum IL-1β,apoptosis rate,TLR4 expression,and p-NF-κB p65/NF-κB p65 than Que-H group,with statistically significant differences(P<0.05).Conclusion:Que can improve cognitive dysfunction and hippocampal neuronal damage in AD rats,which may be related to the inhibition of TLR4/NF-κB pathway.