Objective: To investigate the protective effect of resveratrol on intestinal barrier in 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse models and its mechanism for regulating TLR4/MyD88/NF-κB signaling to protect dopaminergic neurons.
Methods: Fifty-two C57BL/6J mice were randomized into control group (n= 12), MPTP group (n=14), MPTP + resveratrol (30 mg/kg) group (n=13), and MPTP + resveratrol (90 mg/kg) group (n=13), and mouse models were established by intraperitoneal MPTP (30 mg/kg) injection for 7 days in the latter 3 groups. Behavioral tests were conducted to evaluate the effect of resveratrol on motor symptoms of the mice. Western blotting was used to detect the expression of TH, α-syn, ZO-1, Claudin-1, TLR4, MyD88, and NF-κB in the brain tissues of the mice. Immunohistochemistry, immunofluorescence, ELISA and transmission electron microscopy were used to verify the effect of resveratrol for suppressing inflammation and protecting the intestinal barrier.
Results: Compared with those in the normal control group, the mice in MPTP group showed significant changes in motor function, number of dopaminergic neurons, neuroinflammation, levels of LPS and LBP, and expressions of tight junction proteins in the intestinal barrier. Resveratrol treatment significantly improved motor function of the PD mice (P < 0.01), increased the number of neurons and TH protein expression (P < 0.05), down-regulated the expressions of GFAP, Iba-1, and TLR4, lowered fecal and plasma levels of LPS and LBP (P < 0.05), restored the expression levels of ZO-1 and Claudin-1 (P < 0.01), and down-regulated the expressions of TLR4, MyD88, and NF-κB in the colon tissue (P < 0.05). The mice with resveratrol treatment at 30 mg/kg showed normal morphology of the tight junction complex with neatly and tightly arranged intestinal villi.
Conclusion: Resveratrol repairs the intestinal barrier by inhibiting TLR4/MyD88/NF-κB signaling pathway-mediated inflammatory response, thereby improving motor function and neuropathy in mouse models of MPTP-induced PD.
目的: 探讨白藜芦醇（RES）对1-甲基-4-苯基-1, 2, 3, 6-四氢吡啶（MPTP）诱导的帕金森病模型小鼠肠道屏障的保护作用及其调控TLR4/MyD88/NF-κB信号通路的分子机制。
方法: 将52只小鼠随机分为对照组（n=12），MPTP组（n=14），RES低剂量（MPTP+RES30）组（n=13）及高剂量（MPTP+RES90）组（n=13）。利用30 mg/kg MPTP腹腔注射7 d诱导帕金森病小鼠模型，对照组腹腔注射等剂量PBS，治疗组分别利用30 mg/kg和90 mg/kg RES干预3周。小鼠行为学测试分析RES对帕金森模型小鼠运动功能的影响。Western blotting检测RES在TLR4/MyD88/Nf-κB信号通路中发挥的作用。免疫组织化学、免疫荧光、酶联免疫吸附试验和透射电镜检测验证RES抑制炎症和保护肠屏障的作用。
结果: 与对照组相比，MPTP组小鼠在运动功能、多巴胺能神经元数量、神经炎症、LPS和LBP水平以及肠屏障紧密连接蛋白表达水平等方面的差异具有统计学意义（P＜0.05）；RES治疗组与MPTP组相比，运动功能改善(P＜0.01)，神经元数量恢复，TH蛋白表达上调（P＜0.05），GFAP、Iba-1和TLR4的表达下调，粪便、血浆中LPS、LBP水平下降（P＜0.05），ZO-1、Claudin-1的表达恢复（P＜0.01），结肠组织TLR4、MyD88、NF-κB表达下调（P＜0.05，P＜0.01，P＜0.001）。电镜检测结果显示，与MPTP组比较，MPTP+RES30组紧密连接复合体形态正常，肠绒毛排列整齐且紧密。
结论: RES通过抑制肠屏障TLR4/MyD88/NF-κB信号通路介导的炎症反应修复肠屏障，从而改善MPTP诱导的帕金森病小鼠模型的运动功能障碍和神经病变，对多巴胺能神经元发挥保护作用。
Keywords: Parkinson's disease; TLR4; dopaminergic neurons; microbiota-gut-brain axis; resveratrol.