帕金森病大鼠脚桥核中胆碱能M_2受体的表达变化及意义

目的 通过免疫组织化学方法观察胆碱能M_2受体在帕金森病(Parkinson's disease, PD)模型大鼠脚桥核(pedunculopontine nucleus, PPN)中的表达变化,探讨胆碱能M_2受体在PD发病机制及病理生理改变中的作用.方法 选用健康雄性SD大鼠16只,随机分为2组.取脑组织固定后作连续冠状冰冻切片.以鼠源M_2单克隆抗体为一抗,采用免疫组化SP法,镜下控制显色.以阳性细胞计数及平均光密度为分析指标,对M_2受体在PD模型大鼠PPN中的表达变化进行观察分析.结果 对照组大鼠PPN部位及PD大鼠未损毁侧PPN部位均表达比较丰富的M_2受体阳性细胞.PD大鼠损毁侧PPN部位M_2受体阳性细胞明显稀疏.与对照组和PD大鼠未损毁侧相比有明显差异(P<0.05).3组间阳性部位的表达强度无明显差异(P>0.05).结论 PD状态下PPN内存在表达M_2受体的神经元变性死亡或受体脱失.而其余未发生变性死亡或受体脱失的M_2受体阳性神经元其表达强度并不受影响.同时发现,影响PPN内M_2受体阳性细胞变化的因素具有单侧性.

The altered expression of M_2 muscarinic receptor in the neurons of the pedunculopontine nucleus in 6-hydrodopamine unilaterally lesioned rats and its significance

Objective To investigate the altered expression of muscarinic receptor 2 (M_2 receptor) in the pedunculopontine nucleus (PPN) of Parkinson's disease (PD) model rat by immunocytochemical technique and explore the role of M_2 receptor in etiopathogenesis and pathophysiological changes of PD. Methods Sixteen healthy SD rats were divided randomly into two groups. Rat monoclonal antibody against the M_2 receptor was used. Then we used positive cell counting and optical density as indicators to analyze the altered expression of M_2 receptor in PPN of PD model rats. Results The counting of M_2 receptor positive cells in the PPN was not obviously changed in normal rats and the unlesioned side of PD rats (P>0.05), whereas a significant decrease was observed when compared to that in normal rats and the lesioned side of PD rats, respectively (P<0.05). However, the positive intensity in the three groups did not differ significantly. Conclusion The results indicate that there was a degenerative death or receptor loss of M_2 receptor positive cells in the lesioned PPN of PD rats. The expression intensity of M_2 receptor positive cells without degenrative death or receptor loss was not affected. It was also found that the factor affecting the change of M_2 receptor positive cells in the PPN involved only one side.