Abstract: Objective To observe the expression of connexin 36 (Cx36) in the striatum and motor cortex of rat model of Parkinson's disease (PD) in order to explore whether gap junction is involved in the pathogenesis of the cortex-basal ganglia circuit disturbances in PD.  Methods Hemi-parkinsonian rat model was produced by stereotaxically injecting 6-hydroxydopamine (6-OHDA) to right medial forebrain bundle (MFB). Immunohistochemical staining and Western blotting analysis were used to observe the expression changes of Cx36 in the striatum and motor cortex. Double immunofluorescence labeling was used to analyze the expression of Cx36 in enkephalin (ENK) positive medium spiny neurons and Parvalbumin (PV) positive interneurons in the striatum.  Results Immunohistochemical staining showed Cx36 expression was elevated in the right striatum as well as right motor cortex of PD group compared with normal control group (t = 2.474, P = 0.048; t = 2.614, P = 0.040). Double immunofluorescence labeling staining revealed that ENK-positive striatum neurons were elevated (t = 3.987, P = 0.007) and Cx36 expression was increased in ENK-positive striatum neurons (t = 3.271, P = 0.017) in PD group compared with normal control group. While PV-positive interneurons decreased (t = 2.777, P = 0.032) and Cx36 expression was down-regulated in PV-positive interneurons (t = 2.624, P = 0.039) compared with the normal control group. Western blotting indicated that the 6-OHDA lesion induced a significant upregulation of Cx36 to (119.31 ± 8.92)% in comparison with the normal group [(104.05 ± 3.82)%] in right striatum (t = 3.516, P = 0.024). In right motor cortex Cx36 increased to (138.20 ± 17.88)% , induced a significant upregulation of Cx36 in the right motor cortex in comparison with the normal control group [(105.27 ± 2.82)%; t = 4.068, P = 0.015].  Conclusion The Cx36 expression was generally increased in the striatum and motor cortex of PD rat model, with upregulation in ENK-positive striatum neurons but downregulation in PV-positive interneurons, suggesting that gap junction dysfunction may play an important role in the disturbance of cortex-basal ganglia pathway in PD.

Key words: Parkinson disease, Basal ganglia, Gap junctions, Connexins, Immunohistochemistry, Immunoblotting, Disease models, animal

摘要： 目的 观察缝隙连接蛋白36（Cx36）在帕金森病模型大鼠纹状体和运动皮质区的表达变化，并探讨缝隙连接功能异常与帕金森病基底节环路功能紊乱间的关系。方法 采用6-羟多巴胺注射法建立帕金森病动物模型，免疫组织化学染色及Western blotting 法检测纹状体及运动皮质区Cx36 表达变化，免疫荧光双标染色进一步分析纹状体脑啡肽阳性传出神经元及Parvalbumin 阳性中间神经元Cx36表达变化。结果 （1）免疫组织化学染色显示，帕金森病组大鼠右侧纹状体及运动皮质区Cx36 表达水平高于正常对照组（均P < 0.05）。（2）免疫荧光双标染色显示，纹状体脑啡肽阳性神经元数目和Cx36 表达水平高于正常对照组（均P < 0.05），而Parvalbumin 阳性神经元数目和Cx36 表达水平低于正常对照组（均P < 0.05）。（3）Western blotting 法检测显示，帕金森病组大鼠右侧纹状体［（119.31 ± 8.92）%］及运动皮质区［（138.20 ± 17.88）%］Cx36 表达水平高于正常对照组［（104.05 ± 3.82）和（105.27 ± 2.82）%，均P < 0.05］。结论 帕金森病大鼠右侧纹状体及运动皮质区Cx36表达水平升高，纹状体脑啡肽阳性传出神经元Cx36 表达上调，Parvalbumin 阳性中间神经元Cx36 表达下调。提示缝隙连接异常可能参与帕金森病皮质-基底节-皮质环路功能紊乱的发生机制。

关键词: 帕金森病, 基底神经节, 缝隙接合部, 连接蛋白类, 免疫组织化学, 免疫印迹法, 疾病模型, 动物