CCR5第一、第二胞外环特异性结合的拮抗短肽对哮喘小鼠气道炎症反应及Th1迁移的影响

Effect of antagonistic peptides specifically blinding to the first and second extracellular loops of CCR5 on airway inflammation and Th1 migration in asthmatic mice

目的探讨CC趋化因子受体5(CCR5)第一、第二胞外环特异性结合的拮抗短肽(拮抗短肽)对哮喘小鼠气道炎症和辅助性T淋巴细胞1(Th1)迁移的影响和机制.方法40只健康野生型BALB/c小鼠,分为空白对照组(对照组)、致敏组、模型组、GH拮抗短肽治疗组(GH组)、HY拮抗短肽治疗组(HY组),每组各8只.采用卵清白蛋白构建BALB/c小鼠急性哮喘模型,并予CCR5第一、第二胞外环拮抗短肽(分别为GH和HY短肽)干预.通过制备小鼠肺组织切片评估气道炎症浸润及黏液分泌程度,采用ELISA检测小鼠支气管肺泡灌洗液(BALF)IFN-γ表达水平,使用流式细胞仪分别检测小鼠脾脏和外周血Th1比例.结果对照组小鼠肺组织无或仅少量炎症细胞浸润,支气管壁均匀无增厚,无黏液栓;致敏组支气管周围少量炎症细胞浸润,管壁及支气管上皮细胞轻微损伤.与对照组比较,模型组可见大量炎症细胞浸润,以支气管和动静脉周围明显,管壁增厚,出现支气管上皮细胞损伤.GH组、HY组小鼠肺组织炎症浸润程度明显减轻.与模型组相比,GH组和HY组小鼠气道炎症浸润程度明显减轻、气道黏液分泌下降、BALF中IFN-γ水平降低、脾脏中Th1比例上升、外周血中Th1比例下降(P均<0.05).其中,HY组小鼠脾脏中Th1比例高于GH组,外周血中Th1比例低于GH组(P均<0.05).结论CCR5第一、第二胞外环拮抗短肽缓解哮喘小鼠的气道炎症可能是通过抑制Th1向炎症部位趋化实现的.

Objective To investigate the effect and mechanism of antagonistic peptides specifically binding to the first and second extracellular loops of CC chemokine receptor 5(CCR5)on airway inflammation and T-helper cell 1(Th1)migration in the asthmatic mouse models.Methods Forty healthy wild-type BALB/c mice were evenly divided into the blank control group(control group),sensitization group,model group,GH peptide group and HY peptide group.The experimental BALB/c mouse models of acute asthma were induced by OVA,and treated by antagonistic peptides of CCR5(GH and YH peptide).The degree of airway inflammation and mucus hypersecretion were assessed by HE and PAS staining,respectively.The expression level of IFN-γin the bronchoalveolar lavage fluid(BALF)was detected by ELISA.Besides,the proportion of Th1 cells in the spleen and peripheral blood was detected by flow cytometry.Results In the control group,no or slight inflammatory cell infiltration was noted in the lung tissues,no bronchial wall thickening or mucus plug was observed.In the sensitization group,a slight amount of inflammatory cell infiltration was seen surrounding the bronchi,and mild injury was noted in the bronchial wall and epithelial cells.Compared with the control group,a larger quantity of inflammatory cell infiltration was observed,especially surrounding the bronchi and arteriovenous region in the model group.Besides,bronchial wall thickening and bronchial epithelial cell injury were observed.In the GH and HY peptide groups,the severity of inflammatory cell infiltration in the lung tissues was significantly attenuated.Compared with the asthmatic model group,two antagonistic peptides of CCR5 significantly mitigated the allergic airway inflammation and mucus secretion,down-regulated the expression level of IFN-γ,up-regulated the proportion of Th1 cells in the spleen and down-regulated the proportion of Th1 cells in the peripheral blood(all P<0.05).In the HY group,the proportion of Th1 cells in the spleen was significantly higher,whereas that in the peripheral blood was remarkably lower compared with those in the GH group(both P<0.05).Conclusion These findings suggest that antagonistic peptides of CCR5 can alleviate the airway inflammation in the asthmatic mouse models probably by suppressing the Th1 chemotaxis to inflammatory sites.