乙酰胆碱对实验性结肠炎中移动抑制因子活性的影响

Effect of acetylcholine on the activity of migration inhibitory factor in mouse colitis

目的探讨副交感神经在实验性结肠炎中的作用,特别是乙酰胆碱(ACh)对结肠炎中移动抑制因子(MIF)活性的影响。方法以二硝基氯苯(DNCB)灌注小鼠结肠制备结肠炎模型,以免疫荧光染色法测定结肠组织和肠神经元中MIF蛋白的表达,以二苯基四氮唑溴盐(MTT)法测定脾淋巴细胞中MIF的释放。观察腹腔注射(预处理)阿托品或MIF抗体、以及体外ACh干预细胞培养,对结肠炎病理、MIF表达及释放的影响。结果结肠炎小鼠肠组织和肠壁神经元MIF蛋白的表达、淋巴细胞中MIF的释放均随DNCB灌肠液浓度的增大而增多,MIF抗体(1∶5)或阿托品(1μg.g-1体重)预处理可减轻DNCB引起的肠病理改变及MIF的表达和释放。ACh(10-7mol.L-1~10-3mol.L-1)可增加淋巴细胞中MIF的释放,该作用可被阿托品(10-5mol.L-1)共同孵育而阻断(阿托品组与ACh 10-5mol.L-1和10-3mol.L-1组相比,P<0.05,P<0.01)。结论在DNCB引起小鼠结肠炎过程中,内源性ACh的活动增强可能是加重结肠病理和升高炎症因子MIF活性的原因之一。

Aim To explore the role of parasympathetic nerve in experimental colitis,especially the effect of acetylcholine（ACh） on the activity of migration inhibitory factor（MIF） in the colitis.Methods Mouse colitis was induced by 2,4-dinitrochlorobenzene（DNCB） enema.The expression of MIF protein in both the colonic tissue and the enteric neurons was detected by immunofluorescence staining.The lymphocytic MIF activity was measured with methyl thiazolyl tetrazolium（MTT） method.Atropine was intraperitonealy（ip） administered to mouse before DNCB treatment.MIF antibody was given to mouse by enema before DNCB treatment.ACh or atropine＋ACh was added into the lymphocyte culture in vitro during MIF preparation,respectively.Results The expressions of MIF protein both in enteric neuron and in colonic tissue were increased in DNCB-induced colitis in mouse.The MIF activity of lymphocyte was also dose-dependently increased in DNCB treated groups than in the control.Pretreatment of MIF antibody（1 ∶5） or atropine（1 μg·g-1 bw）could attenuate the colonic pathology as well as the MIF activity induced by DNCB.The increased release of MIF by ACh（10-7 mol·L-1-10-3 mol·L-1）could be antagonized by atropine at 10-5 mol·L-1（P〈0.05,P〈0.01 vs ACh 10-5 mol·L^1 and 10-3 mol·L-1,respectively）.Conclusion An excessive activation of the endogenous ACh may be one of the factors aggravating the pathology and MIF expression/release in the DNCB-induced colitis.