脑还丹对快速老化小鼠SAMP/8学习记忆能力及海马APP、Pin1、HMGB1 mRNA表达的影响

Effect of Chinese Medicine Naohuan Dan on Hehavior and the Expression of APP,Pin1,HMGB1 mRNA in the Hippocampus of Senescence Accelerated Mouse SAMP/8

目的:观察脑还丹对快速老化(SAMP/8)小鼠学习记忆能力及海马β-淀粉样蛋白前体蛋白(APP)、肽基脯氨酰顺反异构酶(Pin1)与高迁移率族蛋白Bl(HMGB1)mRNA表达的影响,探讨脑还丹防治阿尔茨海默病(AD)的作用机制。方法:选用6月龄雄性SAMP/8小鼠共30只,随机分为脑还丹高、低剂量组和模型组,另选用6月龄SAMP/1小鼠10只为正常对照组。高、低剂量组分别给予脑还丹84,21 g·kg-1ig;模型组、空白组给予双蒸水10 mL·kg-1,1次/d,连续8周。用Morris水迷宫方法测试小鼠的定位航行和空间探索能力,测试后每组取8只小鼠断头处死,无菌条件下剥出全脑,小心分离海马组织,采用实时荧光定量PCR(qRT-PCR)法检测海马组织中APP,Pin1,HMGB1 mRNA表达。结果:6月龄SAMP/8雄鼠的学习记忆能力明显低于同月龄SAMR/1雄鼠,表现为逃避潜伏期从第2天起显著延长,原平台象限停留时间缩短。脑还丹治疗8周后,SAMP/8小鼠逃避潜伏期明显缩短(P<0.05)。SAMR/1小鼠和用药各组小鼠的记忆保持能力比SAMP/8小鼠强,尤其以脑还丹高剂量组更明显(P<0.05)。与正常组比较,模型组APP mRNA相对表达量上调;与模型组比较,脑还丹高、低剂量组APP mRNA表达下调(P<0.05),高剂量组APP mRNA表达明显低于低剂量组(P<0.05)。与正常对照组比较,模型组Pin1 mRNA表达下调;与模型组比较,脑还丹高、低剂量组Pin1 mRNA表达上调(P<0.05),高剂量组Pin1 mRNA表达显著低于低剂量组(P<0.05);与正常组比较,模型组HMGB1 mRNA表达上调;与模型组比较,脑还丹高、低剂量组HMGB1 mRNA表达下调(P<0.05),高剂量组HMGB1 mRNA表达明显低于低剂量组(P<0.05)。结论:脑还丹治疗8周可改善SAMP/8小鼠的学习能力和记忆缺损。脑还丹可能通过下调SAMP/8小鼠APP,HMGB1 mRNA的表达,上调Pinl mRNA表达,从源头上阻断老年斑及神经元纤维缠结的形成,这可能是脑还丹防治AD的主要作用点之一。

Objective：Through researching the effection of Naohuan Dan （NHD） on behavior and the expression ofβ-amyloid precursor protein （APP）,peptidyl-prolyl cis-trans isomerase A （Pin1） and high mobility group protein Bl （HMGB1） mRNA in the hippocampus of Senescence Accelerrated Mouse SAMP/8,this work discusses partially the mechanism of traditional Chinese medicine NHD with respect to its effectiveness to treat Alzheimer＇ s disease.Method：Sixty six-months old SAMP/8 mice were randomly divided into NHD low and high dose group and model group,10 six-months old SAMR/1 were served as a normal control group.The mice were administered with NHD intragastricly at the dose of 84,21 g ·kg-1 per day for 8 weeks respectively,while distilled water in the model group and normal control group at the dose of 10 mL ·kg-1.8 each analyzed the parameter of place navigationtest and spatial probe test by Morris water maze,then stripped out whole brain under sterile condition,the hippocampus were taken out to expression of APP,Pin1,HMGB1 mRNA by real time quantitative PCR （qRT-PCR）.Result：6 month old male SAMP/8 learning and memory ability was significantly lower than the same month-old SAMR/1 male,specific performance：the escape latency was significantly increased from the second day,the time of stopping on original platform quadrant was shortened.The SAMP/8＇ s escape latency was significantly shortened （P 〈 0.05）.The memory retention in SAMR/1 mice and mice after NHD treatment was stronger than SAMP/8,especially the high dose NHD group was obvious （P 〈 0.05）.The relative expression of APP,Pin1,HMGB1 mRNA was statistical significant difference.In the model group,the level of APP mRNA increased compared with the normal control group （P 〈 0.05） ; the level of APP mRNA of NHD group decreased compared with the model group （P 〈 0.05）.In the model group,the level of Pin1 mRNA decreased compared with the normal control group （P 〈 0.05） ; the level of Pin1 mRNA of NHD group increased compared with the model group （P 〈 0.05） ; In the model group,the level of HMGB1 mRNA increased compared with the normal control group （P 〈0.05）; the level of HMGB1 mRNA of NHD group decreased compared with the model group （P 〈 0.05） ; The effects in the NHD high dose group were all better than those in the low dose group for APP mRNA,Pin1 mRNA and HMGB1 mRNA.Conclusion：Naohua Dan treat SAMP/8 of the more recognized animal model of AD for 8 weeks.Behavior detection was found that Naohuan Dan can improve the learning ability,memory impairment of the SAMP/8.The increased level of APP and HMGB1 mRNA and the decreased level of Pin1 mRNA in the SAMP/8 mice,which probably is part of pathology of Alzheimer＇ s disease.Naohuan Dan can block amyloid plaques and nerve fibers tangles from source through decreacing the APP and HMGB1 level and increscing the Pin1 level.This may be one of the major action points of the treatment of AD by Nanhuan Dan.