灯盏乙素对痴呆大鼠脑组织乙酰胆碱尼古丁受体蛋白及mRNA表达的作用

Effect of Scutellarin on Expressions of Nicotinic Acetylcholine Receptor Protein and mRNA in the Brains of Dementia Rats

目的观察灯盏乙素对痴呆模型大鼠乙酰胆碱尼古丁受体(nAChR)亚单位蛋白质和mRNA水平表达的影响,探讨其可能的作用机制。方法 Wistar大鼠42只,随机分为5组,正常对照组(6只)、假手术组(6只)、学习记忆损伤模型组(6只)、灯盏乙素处理组(10只)和脑复康处理组(10只)。用双侧脑室注射β淀粉样蛋白(Aβ25-35)联合腹腔注射D-半乳糖方法建立痴呆大鼠模型;用灌胃方法分别进行灯盏乙素和脑复康给药处理;用Morris水迷宫方法检测大鼠学习记忆能力;用蛋白质印迹法和实时定量聚合酶链法分别从蛋白质水平和mRNA水平测定大鼠海马组织nAChR亚单位α4、α7及β2表达的变化。结果与正常对照组和假手术组比较,模型组大鼠学习记忆能力下降(P<0.05),α4及α7 nAChR蛋白表达水平明显降低(P<0.05),而β2亚单位改变不明显,3种亚单位nAChR的mRNA表达水平未见改变(P>0.05);用灯盏乙素处理后痴呆大鼠学习记忆能力有较大改善(P<0.05),α4、α7 nAChR蛋白表达水平有所回升(P<0.05);各组大鼠3种亚型nAChR的mRNA表达水平未见改变(P>0.05),灯盏乙素处理组与脑复康处理组比较各检测指标未见明显差异(P>0.05)。结论灯盏乙素可改善痴呆大鼠学习记忆能力,其机制可能与其上调nAChR表达有关。

Objective To observe the effect of Scutellarin（Scu） on expressions of nicotinic acetylcholine receptor（nAChR） subunit protein and mRNA in dementia rats,and to study its possible mechanism on dementia.Methods Forty-two Wistar rats were randomly divided into 5 groups,i.e.,the normal control group（n=6）,the sham-operative group（n=6）,the memory deficit model group,the Scu treatment group（n=10）,and the positive drug（piracetam） control group（n=10）.The dementia rat model was established by bilateral ventricle injection with β-amyloid peptide（Aβ）25-35 and abdominal cavity injection with D-galactose.Rats in the Scu treatment group or the piracetam control group were treated with Scu or piracetam by gastrogavage.The learning and memory ability of rats were detected by Morris water maze test,nAChR α4,α7,and β2 subunits at protein and mRNA levels were detected by Western blot and Real-time PCR respectively.Results Compared with the normal control group and the sham-operative group,the learning and memory ability decreased in rats of the model group（P0.05）.nAChR α4 and α7 subunit protein expressions were obviously lowered（P0.05）,but changes of β2 were not obvious.No obvious change of mRNA expressions in all three nAChR subunits was seen（P0.05）.After treatment of Scu,the learning and memory ability was greatly improved,nAChRs α4 and α7 subunit protein expressions increased in rats with dementia（all P0.05）.No obvious change of mRNA expressions in all three nAChR subunits was seen（P0.05）.No obvious difference of each index was shown between the Scu treatment group and the positive drug（piracetam） control group.Conclusions Scutellarin could improve the learning and memory ability of dementia rats.Its mechanism might be associated with its up-regulation of nAChR expressions.