基于TLR4/NF-κB通路探讨蛤蚧提取物对利血平诱导抑郁大鼠神经炎症的影响

Effect of Gecko Extract on Neuroinflammation in Rats with Reserpine-induced Depression via TLR4/NF-κB Pathway

目的:观察蛤蚧提取物的抗抑郁作用,并探讨其作用机制。方法:腹腔注射利血平(0.5 mg·kg^(-1))诱导大鼠抑郁模型,将造模成功的大鼠随机分为模型组,氟西汀组(1.8 mg·kg^(-1)),蛤蚧提取物高、低剂量组(12,6 g·kg^(-1)),分别给予相应剂量药物,1次/d,连续给药10 d。给药结束后,通过酶联免疫吸附测定(ELISA)法检测大鼠血清和前额皮层中神经递质及炎症因子的水平;通过苏木素-伊红(HE)染色观察大鼠海马组织中细胞的变化情况;通过实时荧光定量聚合酶链式反应(Real-time PCR)检测大鼠海马组织中白细胞介素-6(IL-6),核转录因子-κB(NF-κB),肿瘤坏死因子-α(TNF-α)mRNA的水平;通过蛋白免疫印迹法(Western blot)检测大鼠海马组织中Toll样受体4(TLR4),NF-κB蛋白水平。结果:与正常组比较,蛤蚧提取物能明显缩短大鼠的悬尾不动时间和游泳不动时间;与模型组比较,蛤蚧提取物能明显减少大鼠眼睑下垂现象和圈内保留时间(P<0.05);升高血清中5-羟色胺(5-HT),多巴胺(DA)的水平(P<0.05),降低血清和前额皮层中MAO,IL-6,TNF-α的水平(P<0.05);降低大鼠海马组织中炎症因子IL-6,NF-κB,TNF-αmRNA的水平以及TLR4,NF-κB蛋白的表达(P<0.05,P<0.01);改善大鼠海马组织的病理症状。结论:蛤蚧提取物通过抑制TLR4/NF-κB信号通路,降低大鼠海马组织中NF-κB,IL-6等炎症因子的表达,减轻抑郁病理损伤,从而减轻抑郁症状。

Objective: To investigate the effects and mechanism of Gecko extract for treatment of depression in rats. Method:The depression rats were induced by intraperitoneal injection of reserpine(0.5 mg·kg^(-1)). The successfully modeled rats were randomly divided into model group,fluoxetine group(1.8 mg·kg^(-1)),high dose and low dose groups of Gecko extract(12,6 g·kg^(-1)). The rats were given corresponding dose of drugs once a day for 10 days. After administration,the levels of neurotransmitters and inflammatory factors in serum and prefrontal cortex of rats were detected by enzyme-linked immunosorbent assay(ELISA). The cell changes in hippocampal tissues were observed by hematoxylin-eosin(HE)staining. The mRNA levels of interleukin-6(IL-6),nuclear factor-κB(NF-κB),and tumor necrosis factor(TNF-α)in the hippocampus of rats were detected by Real-time fluorescence quantitative polymerase chain reaction(Real-time PCR). The protein levels of Tolllike receptor 4(TLR4)and NF-κB in hippocampal tissues of rats were detected by Western blot. Result:Compared with the normal group,Gecko extract significantly shortened the immobility time of tail suspension and swimming in mice. Compared with model group,Gecko extract significantly reduced blepharoptosis and retention time in circles for the rats(P<0.05), increased the levels of 5-hydroxytryptamine(5-HT) and dopamine(DA)in serum(P<0.05),decreased the levels of Monoamine oxidase(MAO),IL-6,and TNF-α in serum(P<0.05)and prefrontal cortex(P<0.05),decreased the mRNA levels of inflammatory cytokines IL-6,NF-κB and TNF-α and the protein expressions of TLR4 and NF-κB in the hippocampus of rats(P<0.05,P<0.01), and improved the pathological symptoms of the hippocampus. Conclusion: Gecko extract can significantly alleviate the pathological damage of depression and improve the symptoms of depression,and its mechanism may be due to inhibiting TLR4/NF-κB signaling pathway and reducing the expression of NF-κB,IL-6 and other inflammatory factors in the hippocampus of rats.