肠三叶因子对炎症性肠病小鼠细胞凋亡的调节机制

Mechanism of Regulation of Intestinal Trefoil Factor on Apoptosis in Mice with Inflammatory Bowel Disease

目的探讨肠三叶因子(ITF)对小鼠炎症性肠病(IBD)肠上皮细胞及脾淋巴细胞凋亡的调节作用,分析ITF对IBD的保护作用机制。方法 48只小鼠随机分为3组(n=16):三硝基苯磺酸(TNBS)组,用TNBS建立IBD模型后每只小鼠给予9 g.L-1盐水0.1 mL腹腔注射;基因重组肠三叶因子(rITF)组,建立IBD模型后每只小鼠给以rITF 0.1 mL腹腔注射;乙醇对照组,未造模型小鼠每只给予9 g.L-1盐水0.1 mL腹腔注射。各组均连续5 d注射,第6天评估疾病活动度指数(DAI),处死动物后取其结肠组织及脾脏组织,测定其结肠组织髓过氧化物酶(MPO)活性、应用原位末端标记试剂盒及流式细胞技术检测其肠上皮细胞、脾淋巴细胞凋亡情况及脾淋巴细胞Fas表达情况。结果与TNBS组小鼠相比,rITF组小鼠在死亡只数、大便性状、血便情况、体质量下降情况等临床症状及肠道局部炎症均明显减轻,MPO值显著降低(P<0.05),肠上皮细胞凋亡指数显著下降(P<0.01);乙醇对照组IBD小鼠脾淋巴细胞的凋亡明显不足,且Fas表达下调,但TNBS组与rITF组间凋亡率无显著性差异。结论 ITF对IBD小鼠具有保护作用,并且可能通过调节IBD小鼠肠上皮细胞凋亡水平保护肠上皮细胞,但ITF对脾淋巴细胞的凋亡无调节作用。

Objective To evaluate the effects of intraperitoneal injection intestinal trefoil factor（ITF） on regulation of apoptosis in mice model of inflammatory bowel disease（IBD）,and explore its potential mechanism of protection on IBD.Methods Forty-eight mice were randomly assigned into 3 groups：trinitrobenzenesulfonic acid（TNBS） group,recombinant ITF（rITF） group and ethanol group.After IBD models were established with TNBS,mice in rITF group were treated with rITF and TNBS group were treated with 9 g·L-1 saline for 5 days respectively.On the 6th day,the disease activity index（DAI）,tissue myeloperoxidase（MPO） activity were determined of mice in every group.The levels of apoptosis of epithelial cell of colon and splenic lymphocyte were assessed too.The level of the expression in Fas of the splenic lymphocyte were evaluated.Results Signs of acute colitis including weight loss,bloody stools,diarrhea,number of death,MPO activity and inflammatory index in rITF group were reduced compared with those in TNBS group.Studies of TUNEL and flow cytometry examination demonstrated that rITF treatment reduced the level of apoptosis of epithelial cell of colon but had no effect on splenic lymphocyte compared with controls.Conclusions ITF may ameliorate inflammation bowel disease by inhibiting the uncontrolled apoptosis of colonic epithelial cell.On the other hand,ITF can not regulate apoptosis of splenic lymphocyte.