滋肾平颤颗粒对异动症大鼠行为学及纹状体多巴胺D1受体活性和基因表达的影响

Abstract

目的：观察中药对异动症(levodopa-induced dyskinesias, LID)大鼠行为学和纹状体多巴胺D1受体活性及mRNA表达的影响。方法：6-OHDA构建(Parkinson’s disease, PD)大鼠模型，左旋多巴治疗4周制作LID大鼠模型，将成功建立的LID大鼠，随机分为模型组、中药干预组，另取相同数量的正常大鼠作为正常对照组，治疗四周后观察中药对LID大鼠异常不自主运动(abnormal involuntary move-ment, AIM)评分、剂峰旋转次数的影响；测定大鼠纹状体多巴胺D1受体的最大结合容量(maximum binding capacity, Bmax)和平衡解离常数(equilibrium dissociation constant, KD)；运用实时定量PCR检测多巴胺D1受体mRNA表达。结果：模型组大鼠随着左旋多巴治疗时间的延长，AIM评分及剂峰旋转次数进行性升高；与模型组比较，中药干预后可明显减少异动症大鼠的AIM积分及旋转次数(P < 0.05)。纹状体多巴胺D1受体活性结果显示：两组大鼠与正常对照组比较Bmax升高(P < 0.01)，KD值降低(P < 0.05)，受体活性明显增高，中药治疗可使Bmax降低，KD值升高(P < 0.01)，明显降低D1受体活性；荧光实时定量PCR结果显示模型组大鼠多巴胺D1受体mRNA表达明显上调(P < 0.01)；中药可以显著下调多巴胺D1受体mRNA的表达(P < 0.05)。结论：多巴胺D1受体介导的直接通路过度激活可能是异动症产生的主要机制。中药主要是通过下调多巴胺D1受体活性及基因表达从而有效缓解异动症症状。 Objective: To observe the effects of Traditional Chinese Medicine on neurobehavioral manifestations and the activity and mRNA expression of striatal dopamine D1 receptors of rats with levodo-pa-induced dyskinesias (LID). Methods: The rat model of Parkinson’s disease (PD) was established by 6-OHDA; then, the model of LID in rat was produced by injecting levodopa (LD) and benserazide for 4 weeks. The rats were divided into normal control group, LID model group and TCM interven-tion group. After 4 weeks of treatment, the effect of TCM on abnormal involuntary movement (AIM) score of rats with LID, peak dose rotation and efficacy time of levodopa (LD) were observed. The maximum binding capacity (Bmax) and equilibrium dissociation constant (KD) of striatal dopamine D1 receptors of rats were determined. The mRNA expression of dopamine D1 receptors was assayed by using real-time fluorescent quantitative PCR (FQ-PCR). Result: With the extension of LD treat-ment time, the AIM score and peak dose rotation of rats in the LID model group increased progres-sively. Comparing to the LD model group, TCM intervention could obviously reduce the AIM score and peak dose rotation of rats with LID (P < 0.05). The research of D1 receptor activity showed that level of Bmax increased (P < 0.01) and level of KD reduced (P < 0.01) in the LID model group and the TCM intervention group in comparison to those in the normal control group. The activity of D1 receptor increased obviously. TCM treatment could decrease the Bmax level, increase the KD level (P < 0.01) and lower the activity of D1 receptor. The results of FQ-PCR analysis revealed that the gene expression of D1 receptor was up-regulated in the LID model group (P < 0.01). TCM treatment can decrease over-expressed D1 receptor expression (P < 0.05). Conclusion: Over-activation in di-rect-pathway mediated by dopamine D1 receptor may be the main mechanism of LID. TCM effec-tively relieved LID symptoms through regulating the gene expression and activity of dopamine D1 receptors.