左旋多巴对帕金森病大鼠结肠神经递质的影响

Effects of Levodopa on colonic neurotransmitters of rats model of Parkinson's disease

目的探讨左旋多巴对帕金森病(PD)大鼠模型结肠平滑肌收缩性和神经递质的影响。方法 6-羟多巴胺损毁制备偏侧PD大鼠模型。动物分为对照组、PD组、左旋多巴组、PD+左旋多巴组4组;左旋多巴组和PD+左旋多巴组给予左旋多巴灌胃治疗35 d,对照组和PD组给予生理盐水灌胃治疗35 d;采用生物信号采集分析系统记录各组结肠平滑肌收缩频率和幅度;免疫组织化学SP法观察结肠肌间神经丛神经元型一氧化氮合酶(nN O S)、酪氨酸羟化酶(TH)和乙酰胆碱转移酶(C hAT)的变化;R T-PC R检测nN O S、TH、C hAT m R-N A在结肠的表达。结果①与对照组比较,PD组和PD+左旋多巴组收缩频率和幅度明显下降(P<0.05);与PD组比较,PD+左旋多巴组收缩频率和幅度增加(P<0.05)。②与对照组比较,PD组和PD+左旋多巴组nN O S免疫阳性产物积分光密度(IO D)和nN O S m R N A表达明显升高(P<0.05),TH免疫阳性产物IO D和TH m R N A表达明显降低(P<0.05);与PD组比较,PD+左旋多巴组nN O S免疫阳性产物IO D和m R N A表达降低(P<0.05),TH免疫阳性产物IO D和m R N A表达升高(P<0.05);各组C hAT免疫阳性产物IO D和C hAT m R N A表达无明显差异。结论 PD大鼠结肠收缩性下降,其机制可能与nN O S的增多和多巴胺的减少有关。左旋多巴可改善PD大鼠结肠收缩功能,可能与nN O S的减少和多巴胺的增多有关。

【Objective】 To investigate the effects of Levodopa on the contractility of colon smooth muscle and neurotransmitters of colon of rat Parkinson＇s disease models induced by 6-OHDA.【Methods】 Unilateral 6-hydroxydo-pamine lesioned rat model of PD was established.Rats were divided into control group,untreated PD group,Levodopa group,Levodopa treated PD group.Levodopa group and Levodopa treated PD group were administered with Levodopa once daily for 35 days.Control group and untreated PD group were administered with normal saline solution once daily for 35 days.Observe the contraction frequency and amplitude of colon smooth muscle by biological signal acquisition system.Immunohistochemistry was used to stain myenteric neurons for neuronal nitric oxide synthase（nNOS）,tyrosine hydroxylase（TH） and choline acetyl transferase（ChAT） in colon tissues.In addition,RT-PCR technique was used to analyze the expression of nNOS,TH and ChAT in colon tissues.【Results】 Compared with control group,the frequency and amplitude of colon contraction in untreated PD group and Levodopa treated PD group significantly decreased（P 0.05）;Compared with untreated PD group,the frequency and amplitude of colon contraction in Levodopa treated PD group obviously increased（P 0.05）.Compared with control group,the integrated option density（IOD） of nNOS-immunoresponse（IR） positive products and the levels of nNOS mRNA of colon in untreated PD group and Levodopa treated PD group significantly increased（P 0.05）,the IOD of TH-IR positive products and the levels of TH mRNA of colon in untreated PD group and Levodopa treated PD group significantly decreased（P 0.05）.Compared with untreated PD group,the IOD of nNOS-IR positive products and the levels of nNOS mRNA of colon in Levodopa treated PD group obviously decreased（P 0.05）,the IOD of TH-IR positive products and the levels of TH mRNA of colon in Levodopa treated PD group obviously increased（P 0.05）.The IOD of ChAT-IR positive products and the levels of ChAT mRNA of colon in each groups had no significant difference（P 0.05）.【Conclusions】 The increase of nNOS and decrease of dopamine may be responsible for the dysfunction of colon in rat PD models,the decrease of nNOS and the increase of dopamine may be responsible for the effects of Levodopa on the dysfunction of colon in rat PD models.