CCR5第一、第二胞外环特异性结合短肽对TNBS诱导的结肠炎大鼠MUC-2、EGF、Occludin、TFF3表达的影响

Effects of Antagonistic Peptides Specifically Binding to the First and Second Extracellular Loops of CCR5 on MUC-2,EGF,Occludin and TFF3 Expressions in Rats With TNBS-induced Colitis

背景:肠黏膜反复损伤与修复是炎症性肠病(IBD)的主要病理生理特点。CCR5第一、第二胞外环特异性结合短肽(CCR5拮抗短肽)对实验性结肠炎具有促进黏膜重建作用,但其机制尚未完全明确。目的:探讨CCR5拮抗短肽(GH和HY短肽)对TNBS诱导的结肠炎大鼠结肠组织中黏蛋白2(MUC-2)、表皮生长因子(EGF)、闭锁蛋白(occludin)和三叶因子3(TFF3)表达的影响。方法:36只Sprague-Dawley大鼠随机分为正常对照组、结肠炎模型组、GH短肽干预组和HY短肽干预组。以TNBS制备结肠炎模型。两组干预组分别经尾静脉注射GH和HY短肽。造模后第14天处死大鼠,行结肠炎大体损伤评分,以real-time PCR和蛋白质印迹法检测结肠组织MUC-2、EGF、occludin、TFF3 mRNA和蛋白表达。结果:与结肠炎模型组相比,GH和HY短肽干预组结肠炎大体损伤评分显著降低(P均<0.05),结肠组织MUC-2、EGF、occludin、TFF3表达总体上有所升高。HY短肽的作用优于GH短肽,HY短肽干预组MUC-2、occludin、TFF3 mRNA和蛋白表达以及EGF蛋白表达与结肠炎模型组相比差异显著(P均<0.05),而GH短肽干预组仅EGF、occludin mRNA表达显著升高(P均<0.05)。结论:CCR5拮抗短肽可能通过上调MUC-2、EGF、occludin和TFF3表达促进实验性结肠炎的炎症组织修复,以HY短肽效果更优。

Background:Repeated mucosal injury and repair is the main pathophysiological feature of inflammatory bowel disease(IBD).It has been demonstrated that the antagonistic peptides specifically binding to the first and second extracellular loops of CCR5(CCR5 antagonistic peptides)can promote mucosal reconstruction in experimental colitis,however,the precise mechanism has not been fully clarified.Aims:To investigate the effects of CCR5 antagonistic peptides,including GH peptide and HY peptide,on expressions of mucin 2(MUC-2),epidermal growth factor(EGF),occludin and trefoil factor 3(TFF3)in colon tissue of rats with TNBS-induced colitis.Methods:Thirty-six Sprague-Dawley rats were randomly allocated into four groups:normal control group,colitis model group,and GH and HY peptides intervention groups.TNBS was used to induce experimental colitis.In two intervention groups,GH and HY peptides were injected via tail vein.All the rats were sacrificed on the 14th day after model construction.The macroscopic morphological injury score of colitis was evaluated.The mRNA and protein expressions of MUC-2,EGF,occludin and TFF3 in colon tissue were detected by real-time PCR and Western blotting,respectively.Results:The macroscopic morphological injury score of colitis were significantly lower in GH and HY peptides intervention groups as compared with that in colitis model group(all P<0.05).Simultaneously,the expression levels of MUC-2,EGF,occludin and TFF3 in colon tissue were generalized increased in two intervention groups.The effect of HY peptide was superior to GH peptide.In HY peptide intervention group,the expression levels of MUC-2,occludin and TFF3 mRNA and protein,as well as the expression level of EGF protein were significantly higher than those in model control group(all P<0.05).While in GH intervention group,differences were existed only in EGF and occludin mRNA expressions(all P<0.05).Conclusions:CCR5 antagonistic peptides might promote tissue repair in experimental colitis by upregulating MUC-2,EGF,occludin and TFF3 expressions.HY peptide exerts better performance.