IL-18通过下调KLF4阻碍杯状细胞发育加剧小鼠溃疡性结肠炎

IL-18 aggravated ulcerative colitis by inhibiting the development of goblet cells through KLF4 in mice

摘要:

目的：观察白细胞介素-18（interleukin-18，IL-18）对葡聚糖硫酸钠（dextran sodium sulphate，DSS）溶液诱导的小鼠结肠炎中肠黏膜屏障功能的作用及机制。方法：将成年雄性C57BL/6小鼠随机分为对照组、DSS组（每天给予DSS喂养，连续7 d）、DSS+IL-18组（给予DSS喂养连续7 d，同时给予腹腔注射1 μg IL-18），每天测量小鼠体质量变化，7 d后HE染色检测肠黏膜损伤情况、肠道杯状细胞数量、qPCR及Western blot检测IL-18和Kruppel样转录因子-4（Kruppel-like factors-4，KLF4）的变化。结果：与正常对照组相比，DSS组小鼠体质量明显减轻（P=0.000），肠黏膜损伤，绒毛高度降低，结构紊乱，空泡状杯状细胞数量减少（对照组：43.600±7.092，DSS组：16.000±6.205，P=0.000），IL-18蛋白表达增加（对照组：0.444±0.073；DSS组：0.649±0.062，P=0.006），同时参与杯状细胞分化成熟的KLF4表达减少（对照组：0.934±0.053；DSS组：0.777±0.081，P=0.018）。与DSS组相比，DSS+IL-18组小鼠体质量减轻更加明显（P=0.000），肠黏膜损伤及杯状细胞数量减少加剧（DSS+IL-18组：3.200±2.863，P=0.004），IL-18表达明显增加（0.903±0.037，P=0.002），KLF4表达减少（0.469±0.037，P=0.001）。结论：IL-18加剧小鼠肠黏膜屏障损伤的作用，可能是通过下调生长因子KLF4的表达，阻碍杯状细胞的分化成熟发挥作用。

Abstract:

Objective：To observe the role and mechanism of interleukin-18（IL-18） in intestinal mucosal barrier in dextran sulfate sodium（DSS）-induced colitis in mice. Methods：Mice were randomly divided into three groups：control group，DSS group（fed with DSS continually for 7 days） and DSS+IL-18 group（fed with DSS continually for 7 days and given injections of IL-18）. The weight of the mice were measured every day. Seven days later，colon tissues were collected and histology analysis were performed；goblet cell amount in histological sections was measured；the expression of the IL-18 and Kruppel-like factors-4（KLF4） were analyzed by Western bolt. Results：Compared with control group，the mice weight of DSS group loss significantly（P=0.000）. Damaged intestinal mucosa，reduced villous height，and deterioration of tissue integrity was corroborated by histological examination of distal colon sections performed on DSS group. The number of goblet cell in histological sections showed a dramatic decrease in DSS-treated mice compared to control group（control group：43.600±7.092，DSS group：16.000±6.205，P=0.000）. The protein expression of IL-18 in DSS group increased（control group：0.444±0.073；DSS group：0.649±0.062；P=0.006），but the KLF4 expression decreased（control group：0.777±0.081；control group：0.934±0.053；P=0.018）. Compared with DSS group，the weight of mice in DSS+IL-18 group decreased more significantly（P=0.000），the intestinal mucosa was damaged more severely，the number of goblet cell reduced dramatically（DSS+IL-18 group：3.200±2.863，P=0.004），the expression of IL-18 increased obviously（0.903±0.037，P=0.002），and the expression of KLF4 decreased（0.469±0.037，P=0.001）. Conclusion：IL-18 may aggravate ulcerative colitis by inhibiting the development of goblet cells through KLF4 expression reduction in mice.