红景天苷对脂多糖所致痴呆小鼠Tau蛋白过度磷酸化的作用

Effect of Salidroside on Tau Hyperphosphorylation in dementia mice-induced by liposolysaccharide

目的采用腹腔注射脂多糖(LPS)制备小鼠痴呆模型,观察红景天苷(Sal)对该模型小鼠脑组织Tau蛋白过度磷酸化的影响。方法49只雄性C57BL/6J小鼠随机分成7组:空白组、Sal高剂量对照组、LPS组、LPS+Sal低、中、高剂量组、LPS+多奈哌齐(DP)组。药物干预组小鼠灌胃给予Sal 25、50、100 mg/kg或DP 1 mg/kg,空白组和LPS组小鼠给予同体积双蒸水灌胃,1次/d,连续30 d。从灌胃第15天起,LPS小鼠腹腔注射LPS 250μg/kg,空白组与Sal高剂量对照组小鼠腹腔注射等体积生理盐水,1次/d,连续7d。给药结束前1周,采用Morris水迷宫检测各组小鼠行为学功能;之后处死小鼠取脑,Elisa检测脑组织上清液中炎症因子白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)的水平;Western blot法检测脑组织中IL-1β、IL-6、核因子-κB(NF-κB)的表达水平,以及Tau在S202、T231、S396、S404位点的磷酸化水平及总Tau蛋白的表达水平。结果Morris水迷宫结果显示,与空白组小鼠比较,LPS小鼠在第5、6天找到隐匿平台的时间(逃避潜伏期)明显延迟(P<0.01),而给予Sal和DP后明显缩短了逃避潜伏期(P<0.01);Elisa结果显示IL-1β(P<0.01),IL-6和TNF-α(P<0.05)在LPS组小鼠脑内的水平均较空白组显著增加,而给予Sal高剂量和DP后均不同程度的下降(P<0.05)。Western blot法检测LPS小鼠脑组织中IL-1β,IL-6和NF-κB的蛋白表达水平较空白组显著增加(P<0.01),而给予Sal高剂量和DP后均不同程度的下降(P<0.05;P<0.01)。Tau蛋白磷酸化的结果显示,LPS小鼠脑组织Tau蛋白在S202、T231、S396、S404位点的磷酸化水平均较空白组小鼠增加(P<0.01),给予Sal和DP后不同程度的降低了上述磷酸化位点的水平(P<0.01或P<0.05)。但总Tau蛋白的表达水平在各组没有明显变化。结论红景天苷明显改善腹腔注射LPS导致的痴呆小鼠的行为学功能,并降低脑内Tau蛋白过度磷酸化的水平。

Objective To examine the effects of salidroside(Sal)on Tau hyperphosphorylation in dementia mice induced by intraperitoneal injection of liposolysaccharide(LPS).Methods Male C57BL/6J mice were randomly divided into 7 groups Blank,Sal 100 mg/kg,LPS,LPS+Sal(25,50 and 100 mg/kg),and LPS+donepezil(1 mg/kg)groups.Mice were orally administrated with Sal and donepezil for 30 days.LPS(250μg/kg)was injected to LPS groups for 7 days from the 15th day of the experiments.Morris water maze was performed one week before the end of experiments.Mice were decapitated to collect the brain for interleukin 1 beta(IL-1β),IL-6 and tumor necrosis factor alpha(TNF-α)detection via ELISA and Western blot.The expression of nuclear factor-kappa B(NF-κB),total Tau protein and phosphorylated Tau at S202,T231,S396 and S404 were determined.Results LPS prolonged the escape latency in Morris water maze and increased brain levels of IL-1β,IL-6 and NF-α.Sal reversed LPS effects in a dose-dependent manner(P<0.05),comparable to Blank group.Western blot confirmed that LPS-induced increases in inflammation cytokines and NF-κB were ameliorated by Sal and donepezil(P<0.05).LPS-induced phosphorylation of Tau at S202,S404,S396 and T231 sites was also attenuated following Sal and donepezil treatment(P<0.05).Conclusion Salidroside could significantly improve the behavioral function and decrease the phosphorylation levels of Tau protein in the brain of LPS-induced dementia mice.