肉桂醛对利血平致帕金森病大鼠模型改善作用的初步研究

Improvement effect of cinnamaldehyde on reserpine-induced Parkinson′s disease rat model

为研究肉桂醛对利血平诱导的帕金森病(Parkinson′s disease,PD)大鼠模型的神经保护作用机制,72只雄性Wistar大鼠随机分为空白组、模型组、阳性药(美多芭)组以及肉桂醛高、中、低剂量组。除空白组外,其余各组每隔1 d上午腹腔注射利血平1次(0.1 mg·kg-1),同时每天下午灌胃肉桂醛和美多芭溶液。实验过程中进行旷场实验、转棒实验及口腔咀嚼运动评估。实验结束时取脑并固定,地高辛荧光原位杂交法检测多巴胺受体D1(dopamine receptor D1,DRD1)的阳性表达;酶联免疫吸附法(enzyme-linked immunosorbent assay,ELISA)检测脑中多巴胺(dopamine,DA)、3,4-二羟基苯乙酸(3,4-dihydroxyphenylacetic acid,DOPAC)等神经递质含量的变化;RT-PCR和Western blot检测黑质区酪氨酸羟化酶(tyrosine hydroxylase,TH)和α-突触核蛋白(α-synuclein,α-Syn)mRNA和蛋白表达水平。结果显示,注射利血平后,模型组大鼠毛色变黄变脏,拒捕行为减弱,体质量减少,自发活动行为与探索行为减少,协调运动能力下降,口腔咀嚼次数增多,认知能力下降,中脑黑质(substantia nigra,SN)区DRD1阳性表达面积占比下降,TH蛋白及mRNA表达下调,α-Syn蛋白及mRNA表达上调。肉桂醛干预后,对PD模型动物有明显疗效,大鼠自发运动行为、在棒停留时间、运动时间及运动距离、站立次数增加,口腔咀嚼次数减少;黑质中DRD1阳性表达面积占比增多,α-Syn蛋白及mRNA表达下调,TH蛋白及mRNA表达上调,且脑中DA、DOPAC和高香草酸(homovanillic acid,HVA)神经递质水平上调。该研究可为临床治疗及预防PD提供新的实验依据。

In order to study the neuroprotective mechanism of cinnamaldehyde on reserpine-induced Parkinson′s disease(PD)rat models,72 male Wistar rats were randomly divided into blank group,model group,Madopar group,and cinnamaldehyde high-,medium-,and low-dose groups.Except for the blank group,the other groups were intraperitoneally injected with reserpine of 0.1 mg·kg-1 once every other morning,and cinnamaldehyde and Madopar solutions were gavaged every afternoon.Open field test,rotarod test,and oral chewing movement evaluation were carried out in the experiment.The brain was taken and fixed.The positive expression of dopamine receptor D1(DRD1)was detected by TSA,and the changes in neurotransmitters such as dopamine(DA)and 3,4-dihydroxyphenylacetic acid(DOPAC)in the brain were detected by enzyme-linked immunosorbent assay(ELISA).The protein and mRNA expression levels of tyrosine hydroxylase(TH)andα-synuclein(α-Syn)in substantia nigra(SN)were detected by RT-PCR and Western blot.The results showed that after the injection of reserpine,the hair color of the model group became yellow and dirty;the arrest behavior was weakened,and the body weight was reduced.The spontaneous movement and exploration behavior were reduced,and the coordination exercise ability was decreased.The number of oral chewing was increased,but the cognitive ability was decreased,and the proportion of DRD1 positive expression area in SN was decreased.The expression of TH protein and mRNA was down-regulated,and that of α-Syn protein and mRNA was up-regulated.After cinnamaldehyde intervention,it had an obvious curative effect on PD model animals.The spontaneous movement behavior,the time of staying in the rod,the time of movement,the distance of movement,and the number of standing times increased,and the number of oral chewing decreased.The proportion of DRD1 positive expression area in SN increased,and the protein and mRNA expression levels ofα-Syn were down-regulated.The protein and mRNA expression levels of TH were up-regulated.In addition,the levels of DA,DOPAC,and homovanillic acid(HVA)neurotransmitters in the brain were up-regulated.This study can provide a new experimental basis for clinical treatment and prevention of PD.