异常增加的α-突触核蛋白对帕金森病模型小鼠黑质及结肠多巴胺受体D1的表达影响

Effect of abnormally increasedα⁃synuclein on the expression of dopamine receptor D1 in the substantia nigra and colon of Parkinson′s disease model mice

目的探讨异常增加的α-突触核蛋白(α-Syn)对小鼠脑及结肠多巴胺受体D1(D1DR)表达备小鼠帕金森病(PD)模型,对照组注射等体积PBS;术后6个月进行平衡杆、爬杆及旷场实验检测小鼠行为学差异;通过Western blot(WB)、免疫组化及免疫荧光检测黑质及结肠D1DR、α-Syn、酪氨酸羟化酶(TH)的表达情况。结果与对照组相比,模型组小鼠出现平衡杆和爬杆运动时间延长、旷场平均运动速度减慢(P <0.001)等运动迟缓表现;WB、免疫组化及免疫荧光结果显示,模型组小鼠黑质及结肠D1DR、呈正相关(r=0.8943、0.9026,P <0.05)。结论通过脑纹状体注射α-Syn PFF建立的PD模型小鼠黑质及结肠中D1DR、TH表达降低,为结肠活检应用于评估早期PD患者中枢神经病理提供了实验基础。

Objective To investigate the effect of abnormally increasedα⁃synuclein(α⁃Syn)on the expression of Dopamine receptor D1(D1DR)in the brain and colon of mice.Methods Sixteen C57BL/6J mice were randomly divided into control and model groups:the model group was injected withα⁃Syn preformed fibrils(PFF)into the striatum to build a mouse Parkinson′s disease(PD)model,and the control group with equal volume of PBS.Balance beam,pole⁃climbing and open field tests were performed to detect their behaviors at 6 months after operation;Western blot(WB),immunohistochemistry(IHC)and immunofluorescence(IF)were used to detect the expressions of D1DR,α⁃Syn,and tyrosine hydroxylation(TH)in the substantia nigra and colon.Results Compared with the controls,the model mice exhibited prolonged time in balance beam and pole⁃climbing(P<0.001),and slower average moving speed in open field test(P<0.001).By WB,IHC and IF,the D1DR and TH positive cells were significantly reduced in number(all P<0.05)and the expressions of D1DR and TH in the substantia nigra and colon of the model mice were lower than those in the control group(all P<0.05).The relative expression in the substantia nigra and colon was positively correlated(r=0.8943,0.9026,P<0.05).Conclusion The expressions of D1DR and TH are decreased in the substantia nigra and colon of PD model mice built by injection ofα⁃Syn PFF into the striatum,which provides a basis for application of colon biopsy to the path⁃ological assessment of central nerves of early PD patients.