姜黄素对阿尔茨海默病模型大鼠学习记忆能力、海马结构及脑脊液中Aβ_(1-42)和tau蛋白含量的影响研究

Effect of curcumin on abilities of learning and memory,morphological structure of hippocampus,cerebrospinal fluid concentration of Aβ_(1-42) and tau proteins in Alzheimer's disease rat models

目的研究姜黄素(Cur)对阿尔茨海默病(Alzheimer's disease,AD)模型大鼠学习记忆能力、海马结构及脑脊液(cerebrospinal fluid,CSF)中β淀粉样蛋白(Aβ1-42)和tau蛋白含量的影响。方法采用Morris水迷宫筛选出平均逃避潜伏期(average escape latency,AEL)稳定的二级雄性Wistar大鼠45只,随机分为假手术组(Con)、AD模型组、Cur给药组,每组15只。采用D-半乳糖腹腔注射联合Aβ25-35海马立体定位的方法制作AD模型。用二甲基亚砜(DMSO)和生理盐水将Cur溶解成50 mg/ml,Cur组以4 ml/kg腹腔注射,1次/d;Con组和AD组注射等体积的DMSO和生理盐水。治疗14 d后,每组随机选取9只大鼠进行Morris水迷宫测试大鼠学习和记忆能力的变化,用HE染色光镜观察海马组织结构的变化;各组6只大鼠用1 ml注射器经枕骨大孔由延髓池抽取CSF,酶联免疫吸附实验(ELISA)检测CSF中Aβ1-42和tau蛋白含量。结果与Con组比,AD组AEL延长(P<0.05或P<0.01),目标象限停留时间短(P<0.01),穿越平台次数少(P<0.01);海马神经元部分固缩、深染;CSF中Aβ1-42含量明显降低(P<0.01),tau蛋白含量明显升高(P<0.01)。与AD组比,Cur组AEL缩短(P<0.05或P<0.01),目标象限停留时间长(P<0.01),穿越平台次数多(P<0.05);海马神经元固缩、深染减少;CSF中Aβ1-42含量显著升高(P<0.01),tau含量明显降低(P<0.01)。结论 Cur可提高AD模型大鼠的学习和记忆能力,减轻海马组织结构的损伤,其生物学作用可能与提高CSF中Aβ1-42的水平和降低tau蛋白的水平有关。

Objective To investigate the effect of curcumin （Cur） on the ability of learning and memory, the morphological structure of hippocampus, eerebrospinal fluid （CSF） concentration of beta-amyloid （ Aβ1-42 ） and tau proteins in Alzheimer＇s disease （AD） rat models. Methods Forty-five male Wistar rats with stable escape latency tested by Morris water maze were randomly divided into control group （ Con ）, AD model group （ AD ） and Cur administration group （Cur） （ n = 15 ）. D-galactose intraperitoneal injection was combined with Aβ25-35 hippocampus stereotactic injection to establish the AD rat models. The Cur group was administered with Cur（ Sigma, USA） dissolved in DMSO and 0. 9% NaCl at the concentration of 50 mg/ml, and the dose of Cur was determined according to their relative body mass （200 mg/kg）. Rats in Con and AD groups were treated with the same volume of DMSO and 0.9% NaCl. Fourteen days after treatment, nine rats of each group were randomly selected to test learning and memory abilities by Morris water maze. Hippoeampus morphological structure was observed under an optical microscope after hematoxylin and eosin dye （HE） staining. CSF was extracted from six rats in each group from the cistern through the foramen magnum using 1 ml syringe. Enzyme-linked immunosorbent assay （ELISA） was used to detect the CSF concentration of Aβ1-42 and tau proteins. Results Compared with the Con group, the average escape latency （AEL） of AD group was significantly longer （P 〈0.05 or P 〈0.01 ）, the time spent in the quadrant was shorter （P 〈 0.01 ）, the number of crossings was smaller （ P 〈 0.01 ）, more neurons were dark and pyknotic, CSF concentration of Aβ1-42was significantly lower （ P 〈 0.01 ）, and tau protein was obviously higher （P 〈0.01 ）. Compared with AD group, the AEL of Cur group was significantly shorter （P 〈0.05 or P 〈0.01 ）, the time spent in the quadrant was longer （P 〈 0.01 ）, the number of crossings was smaller（ P 〈 0.05 ）, fewer neurons were dark and pyknotic, CSF concentration of Aβ1-42 in the Cur group was notably higher （P 〈 0.01 ） and tau protein was distinctly lower （ P 〈 0.01 ）. Conclusion Cur can improve the learning and memory abilities of AD rats and attenuate the injury to hippocampus. The mechanism might be closely associated with the increase of the CSF concentration of Aβ1-42and decreaseof tau protein.