CCR5第一和第二胞外环特异性结合短肽对大鼠结肠炎的炎症细胞浸润及NF-κB/TNF-α信号通路的影响

Effects of antagonistic peptides specifically binding to the first and second extracellular loops of CCR5 on inflammatory cell infiltration and NF-κB/TNF-α signaling pathway in rats colitis

目的研究CC趋化因子受体5(CCR5)第一和第二胞外环特异性结合短肽对三硝基苯磺酸(TNBS)诱导的SD大鼠结肠炎的炎症细胞浸润及NF-κB/TNF-α信号通路的影响。方法采用5%TNBS构建大鼠结肠炎模型,分别给予2种CCR5短肽干预,通过病理细胞学分析、蛋白免疫印迹法、PCR等方法分别评估其组织学、基因及蛋白质水平的变化。结果与模型组相比,2组给予CCR5拮抗短肽的大鼠均表现为结肠炎组织学损伤减轻(P均<0.05),镜下可见中性粒细胞、淋巴细胞及巨噬细胞浸润减少(P均<0.05)。同时,NF-κB/TNF-α信号通路相关的蛋白及mRNA表达水平也较之模型组明显下降(P均<0.05)。结论特异性结合CCR5第一和第二胞外环的短肽可明显抑制TNBS诱导的SD大鼠结肠炎症,其机制可能是通过抑制NF-κB/TNF-α信号通路的激活。

Objective To investigate the effect of the specific binding of antagonistic peptides to the first and second extracellular loops of CC chemokine receptor 5（ CCR5） upon the inflammatory cell infiltration and NF-κB/TNF-α signaling pathway in SD rats with colitis induced by trinitrobenzene sulfonic acid（ TNBS）.Methods The experimental SD rat models with colitis were induced by 5% TNBS,and intervened by two antagonistic peptides of CCR5. Pathological cytological analysis,western blot and PCR were performed to examine the histological changes of colon,proteins and mRNA levels of the NF-κB/TNF-α signaling pathway. Results Compared with model group,the histological injuries of colitis were alleviated after administration of two antagonistic peptides of CCR5（ both P 〈0. 05）. The infiltration of neutrophils,lymphocytes and macrophages in rats treated with GH and HY peptides was significantly reduced（ all P〈 0. 05）. Besides,the expression levels of the proteins and mRNAs related to the NF-κB/TNF-α signaling pathway were also significantly down-regulated（ all P〈 0. 05）. Conclusions Antagonistic peptides specifically binding to the ECL1 and ECL2 of CCR5 can evidently inhibit the inflammation in SD rats with TNBS-induced colitis,probably by suppressing the activation of the NF-κB/TNF-α signaling pathway.