GR 125487加剧帕金森病模型小鼠运动障碍和促进肠道炎症的研究

GR 125487 aggravates motor dysfunction and potentiates colonic inflammation in Parkinson´s disease model mice

目的探究5-羟色胺受体在帕金森病模型小鼠肠道表达及5-羟色胺4受体对帕金森病模型小鼠运动功能、神经递质及肠道炎症的作用。方法通过RT-qPCR方法检测帕金森病模型小鼠回肠、结肠的5-羟色胺受体mRNA表达水平(Htr1a,Htr1b,Htr1f,Htr2a,Htr2c,Htr4,Htr6和Htr7);将C57BL/6N小鼠随机分成生理盐水组(saline组)、模型组(MPTP组)、5-羟色胺4受体拮抗剂+MPTP组(GR 125487+MPTP组)3组。在第1~5 d连续5 d腹腔注射1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine,MPTP)建立小鼠帕金森病模型。连续16 d每天腹腔注射5-羟色胺4受体拮抗剂GR 125487以探究5-羟色胺4受体对帕金森病模型小鼠的作用。最后一天给药后进行小鼠行为学测试,测试完成后收集小鼠纹状体及结肠组织。通过高效液相色谱法检测纹状体内多巴胺(dopamine,DA)及其代谢物含量,通过Western blot方法检测结肠内CD11b的蛋白表达水平。结果RT-qPCR结果显示,与Saline组相比,MPTP组小鼠回肠、结肠Htr4显著升高(P<0.05)。行为学结果显示,MPTP组小鼠运动能力显著下降(P<0.01),而GR 125487+MPTP组小鼠运动障碍加剧(P<0.05);HPLC结果显示,MPTP组纹状体DA显著减少,DA代谢率显著升高,而GR 125487+MPTP组小鼠进一步减少脑内DA水平,增加DA代谢率;Western blot结果显示,CD11b在GR 125487+MPTP组小鼠结肠表达水平相比于MPTP组表达水平显著上升(P<0.05)。结论Htr4在MPTP诱导的帕金森病模型小鼠肠道表达异常,5-HT4受体拮抗剂可以加剧帕金森病模型小鼠运动障碍、神经递质丢失并促进肠道炎症。

Objective To investigate the expression of serotonin receptors of gut in Parkinson´s disease model mice and to investigate the role of 5-HT4 receptor in motor ability,neurotransmitter and gut inflammation in PD model mice.Methods The mRNA of serotonin receptors(Htr1a,Htr1b,Htr1f,Htr2a,Htr2c,Htr4,Htr6 and Htr7)were detected in Parkinson´s disease model mice ileum and colon by qRT-PCR.C57BL/6N mice were randomly divided into normal saline group,MPTP and GR 125487+MPTP group.The mice received intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine(MPTP)on day 1-5 for 5 consecutive days to build Parkinson´s disease model.To investigate the effect of serotonin 4 receptor on Parkinson´s disease model mice,the mice Behavioral tests were conducted after the last treatment injection.The striatum and colon were collected after the behavioral test.Striatal dopamine and its metabolites were detected by HPLC.Protein expression levels of CD11b in colon was detected by western blot.Results Ileac and colonic Htr4 increased in MPTP group by qRT-PCR analysis,compared with saline group(P<0.05).The results of behavioral test showed that the motor ability of mice in MPTP group decreased(P<0.01),compared with saline group,while GR 125487+MPTP group mice aggravated motor dysfunction in PD mice(P<0.05).HPLC analysis showed that striatal dopamine decreased and dopamine turnover increased in MPTP group.GR 125487+MPTP group mice further decreased DA level and increased DA turnover.Western blot results showed CD11b expression in GR 125487+MPTP group was significantly higher than that in MPTP group(P<0.05).Conclusion The expression of Htr4 is abnormally changed in the gut of MPTP-induced Parkinson´s disease model mice.5-HT4 receptor antagonist can exacerbate motor dysfunction,neurotransmitter loss and promote intestinal inflammation in Parkinson´s disease model mice.