柚皮苷通过P2X7受体减轻HIV-1包膜糖蛋白gp120导致大鼠神经功能损害的的作用及机制

人类免疫缺陷病毒-1(Human immunodeficiency virus-1,HIV-1)包膜糖蛋白gp120能够引起大鼠出现学习记忆障碍的行为学改变并增加海马中P2X7受体的表达;柚皮苷对gp120引起的行为学改变及P2X7表达增多具有改善作用。为了研究柚皮苷通过减少P2X7受体表达减轻gp120导致大鼠神经功能损害的作用及机制,本实验选择SD大鼠并分为假手术操作的对照组、脑室注射gp120的gp120组、脑室注射gp120及不同剂量柚皮苷灌胃的柚皮苷组、脑室注射BzATP的BzATP组、脑室注射gp120、BzATP及90mg/kg柚皮苷灌胃的90mg/kg/d柚皮苷+BzATP组。Morris水迷宫检测逃避潜伏期及错误次数,TUNEL法检测海马中细胞凋亡率,Elisa法检测海马中肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)、白介素-1β(Interleukin-1β,IL-1β)、白介素-6(Interleukin-6,IL-6)的含量,Western blot检测海马中P2X7受体的表达。结果显示:与对照组比较,gp120组大鼠的逃避潜伏期延长,错误次数及海马中细胞凋亡率、TNF-α、IL-1β、IL-6的含量、P2X7受体的表达水平增加(P<0.05);与gp120组比较,不同剂量柚皮苷组大鼠的逃避潜伏期缩短,错误次数及海马中细胞凋亡率、TNF-α、IL-1β、IL-6的含量、P2X7受体的表达水平减少(P<0.05);与90mg/kg/d柚皮苷组比较,90mg/kg/d柚皮苷+BzATP组大鼠的逃避潜伏期延长,错误次数及海马中细胞凋亡率、TNF-α、IL-1β、IL-6的含量、P2X7受体的表达水平增加(P<0.05)。本研究的结果表明柚皮苷减轻HIV-1包膜糖蛋白gp120诱导的神经功能损害,这一作用与抑制海马组织中P2X7受体表达并减轻炎症反应及细胞凋亡有关。创新在于首次阐明了柚皮苷减轻HIV-1包膜糖蛋白gp120诱导神经功能损害的分子机制。在gp120引起大鼠行为学改变及海马组织中细胞凋亡、炎症反应激活的过程中,柚皮苷通过抑制P2X7受体的表达来改善行为学改变、抑制细胞凋亡及炎症反应的激活。

How Naringin Alleviates gp120-induced Neurologic Impairment in Rats via the P2X7 Receptor

Glycoprotein gp120 of human immunodeficiency virus(HIV)-1 causes behavioral changes in learning as well as memory impairment in rats,and increases expression of the P2X7 receptor in hippocampi.Naringin can improve the behavioral changes and P2X7 expression induced by gp120.We wished to study how naringin alleviated gp120-induced neurologic impairment by reducing expression of the P2X7 receptor.Sprague–Dawley rats were divided into several groups:control(sham operation),gp120(intraventricular injection of gp120),naringin(intraventricular injection of gp120 and gavage administration of different doses of naringin),BzATP(intraventricular injection of BzATP),and 90 mg/kg naringin+BzATP(intraventricular injection of gp120,BzATP,and gavage administration of 90 mg/kg naringin).Then,the Morris water maze was used to detect escape latency and number of errors.The TUNEL assay was employed to measure apoptosis in hippocampi.Enzyme-linked immunosorbent assays were used to measure levels of tumor necrosis factor(TNF)-α,interleukin(IL)-1βand IL-6 in hippocampi.Western blotting was employed to measure expression of the P2X7 receptor in hippocampi.Compared with the control group,the escape latency was prolonged,error number,apoptosis rate,levels of TNF-α,IL-1β,IL-6,and expression of the P2X7 receptor in hippocampi increased in the gp120 group(P<0.05).Compared with the gp120 group and control group,the escape latency was shortened,error number,apoptosis rate,levels of TNF-α,IL-1β,IL-6,and expression of the P2X7 receptor in hippocamp ireduced upon treatment with different doses of naringin(P<0.05).Compared with the 90 mg/kg naringin group,the escape latency was prolonged,error number,apoptosis rate,levels of TNF-α,IL-1β,IL-6,and expression of the P2X7 receptor in the hippocampus increased in the 90 mg/kg naringin+BzATP group(P<0.05).These results showed that naringin reduced the neurologic impairment induced by HIV-1 gp120,which was related to inhibition of expression of the P2X7 receptor and alleviation of inflammation and apoptosis in hippocampi.We elucidated,for the first time,the molecular mechanism of action of naringin in reducing the neurologic impairmentinduced by HIV-1 gp120.During gp120-induced behavioral changes,activation of apoptosis,and the inflammatory response in hippocampi,naringin could improve behavioral changes,and inhibit activation of apoptosis and the inflammatory response by inhibiting expression of the P2X7 receptor.