运动预适应对C57BL/6小鼠溃疡性结肠炎的预防作用及其机制分析

摘要

为探讨运动预适应对溃疡性结肠炎(UC)的影响及其可能机制，将24只C57BL/6小鼠随机分为运动预适应组(Ex组)、模型组(DSS组)和安慰剂对照组(C组)，每组8只。Ex组进行8周跑台运动，DSS组和C组安静状态饲养8周。随后Ex组和DSS组自由饮用质量分数为3.5%葡聚糖硫酸钠(DSS)溶液诱导小鼠UC模型，C组自由饮用同等量的蒸馏水，每天观察并记录疾病活动指数(DAI)。7 d后处死小鼠，取肠道炎症组织观察病理变化并进行炎症评分；实时荧光定量PCR(RT-qPCR)法检测白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)mRNA 表达水平；Western blot法检测Toll样受体4(TLR4)、总NF-κB p65和核NF-κB p65蛋白表达水平。结果显示，DSS组出现典型的UC临床表现和组织病理学变化，DAI评分、组织炎症评分、IL-1β和TNF-αmRNA表达以及TLR4和核NF-κB p65蛋白表达水平均高于C组(P<0.01)；Ex组症状和组织病理学变化较DSS组减轻，DAI评分、组织炎症评分、IL-1β和TNF-αmRNA表达以及TLR4和核NF-κB p65蛋白表达水平均低于DSS组(P<0.01)；3组总NF-κB p65蛋白水平差异无显著性(P>0.05)。结果表明，长期中等强度运动预适应能够预防UC、减轻UC病情，其机制可能与抑制TLR4﹣NF-κB信号通路以及下调下游炎症因子基因表达有关。%In order to probe into the effects of exercising preadaptation on ulcerative colitis and its possible mecha-nism, the authors divided 24 C57BL/6 mice randomly into an exercising adaptation group (Ex), a model group (DSS) and a placebo control group (C), each of which contained 8 mice, let the mice in group Ex exercise on a treadmill for 8 weeks, feed the mice in groups DSS and C in a calm condition for 8 weeks, then let the mice in groups EX and DSS drink a 3.5%dextran sulfate sodium (DSS) solution freely to induce a mouse UC model, let the mice in group C drink the same amount of distilled water freely, observed and recorded disease activity index eve-ryday, and 7 days later, killed the mice, took out inflamed intestinal tissues, observed their pathological changes and gave them an inflammation score, measured interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) mRNA ex-pression levels by means of real-time florescence quantification PCR (RT-qPCR), as well as Toll-like receptor 4 (TLR4), total nuclear factor-κB (NF-κB) p65 and nuclear NF-κB p65 protein expression levels by means of Western blot, and revealed the following findings: the mice in group DSS showed typical UC clinical manifestations and histopathological changes, their DAI score, tissue inflammation score, IL-1βand TNF-αmRNA expression levels as well as TLR4 and nuclear NF-κB p65 protein expression levels were all higher than those of the mice in group C (P<0.01);the symptoms and histopathological changes of the mice in group Ex were alleviated as compared with the mice in group DSS, their DAI score, tissue inflammation score, IL-1βand TNF-αmRNA expression levels as well as TLR4 and nuclear NF-κB p65 protein expression levels were all lower than those of the mice in group DSS (P<0.01);there was no significant difference in total NF-κB p65 protein expression level between the mice in these three groups. The said findings indicate that long-term medium intensity exercising preadaptation can prevent UC and alleviate UC condition, and that its mechanism may be related to suppressing the signal pathway of TLRs﹣NF-κB and down-regulating the gene expression of downstream inflammatory factors.