鸢尾黄素通过调节TLR4/MyD88/NF-κB信号通路改善血管性痴呆大鼠认知缺陷

Tectorigenin improves cognitive deficits in rats with vascular dementia by regulating TLR4/MyD88/NF-κB signaling pathway

目的:分析鸢尾黄素通过调节Toll样受体4(TLR4)/髓样分化因子88(MyD88)/核因子κB(NF-κB)信号通路改善血管性痴呆(VD)大鼠认知缺陷的作用。方法:72只大鼠随机分为假手术组、模型组、鸢尾黄素低、中、高剂量[25、50、100 mg/(kg·d)]组和阳性对照组[吡拉西坦324 mg/(kg·d)],每组12只。除假手术组外,其余组大鼠均复制VD模型。建模成功后,鸢尾黄素不同剂量组和阳性对照组分别灌胃不同剂量鸢尾黄素、吡拉西坦,其余组灌胃等剂量生理盐水,连续灌胃28 d。Morris水迷宫实验检测空间学习记忆能力。高效液相色谱-电化学检测海马组织间液神经递质水平。RT-qPCR和Western blot检测海马组织脑源性神经营养因子(BDNF)、高亲和力受体酪氨酸激酶(TrkB)表达。Western blot检测海马组织TLR4/MyD88/NF-κB途径相关蛋白。结果:与假手术组相比,模型组大鼠逃避潜伏期延长,目标区域停留时间和穿越平台次数降低(P<0.05);与模型组相比,鸢尾黄素中、高剂量组逃避潜伏期缩短,目标区域停留时间和穿越平台次数增加(P<0.05)。模型组去甲肾上腺素(NE)、多巴胺(DA)、5-羟色胺(5-HT)和5-羟吲哚乙酸(5-HIAA)水平低于假手术组(P<0.05),鸢尾黄素中、高剂量组NE、DA、5-HT和5-HIAA水平高于模型组(P<0.05)。与假手术组相比,模型组BDNF、TrkB mRNA和蛋白水平降低,TLR4、MyD88、p-NF-κB p65/NF-κB p65蛋白水平上升(P<0.05);与模型组相比,鸢尾黄素中、高剂量组BDNF、TrkB mRNA和蛋白水平上升,TLR4、MyD88、p-NF-κB p65/NF-κB p65蛋白水平降低(P<0.05)。结论:鸢尾黄素可改善VD大鼠认知缺陷,可能通过调节TLR4/MyD88/NF-κB信号通路实现。

Objective:To analyze effects of tectorigenin on improving cognitive deficits in rats with vascular dementia(VD)by regulating Toll-like receptor 4(TLR4)/myeloid differentiation factor 88(MyD88)/nuclear factor-κB(NF-κB)signaling pathway.Methods:A total of 72 rats were randomly divided into sham operation group,model group,low,medium and high doses[25,50,100 mg/(kg·d)]tectorigenin groups and positive control group[piracetam 324 mg/(kg·d)],with 12 rats in each group.Except for sham operation group,VD models were replicated in other groups.After successful modeling,different doses tectorigenin groups and positive control group were administered intragastrically with different doses of tectorigenin and piracetam,while other groups were administered intragastrically with same volume of normal saline for 28 d.Spatial learning and memory ability were detected by Morris water maze.Neurotransmitter levels in hippocampus interstitial fluid were detected by high performance liquid chromatography-electro-chemical.Brain-derived neurotrophic factor(BDNF)and tyrosine kinase receptor b(TrkB)expressions in hippocampus were detected by RT-qPCR and Western blot.TLR4/MyD88/NF-κB pathway-related proteins in hippocampus were detected by Western blot.Results:Compared with sham operation group,escape latency was longer,while stay time in target area and times of crossing platform were lower in model group(P<0.05).Compared with model group,escape latency was shorter,while stay time in target area and times of crossing platform were higher in medium and high doses tectorigenin groups(P<0.05).NE,DA,5-HT and 5-HIAA levels in model group were lower than those in sham operation group(P<0.05),which were higher in medium and high doses tectorigenin groups than model group(P<0.05).Compared with sham operation group,BDNF and TrkB mRNA and proteins levels were lower,while TLR4,MyD88 and p-NF-κB p65/NF-κB p65 proteins levels were higher in model group(P<0.05).Compared with model group,BDNF and TrkB mRNA and proteins levels were higher,while TLR4,MyD88 and p-NF-κB p65/NF-κB p65 proteins levels were lower in medium and high doses tectorigenin groups(P<0.05).Conclusion:Tectorigenin can improve cognitive deficits in VD rats,which may be related to regulating TLR4/MyD88/NF-κB signaling pathway.