应用基因重组人粒细胞集落刺激因子治疗小鼠炎症性肠病的作用机制

Mechanisms underlying therapeutic effects of recombinant human granulocyte colony-stimulating factor against TNBS-induced experimental colitis in mice

目的:本研究主要探讨基因重组人粒细胞集落刺激因子(recombinant human granulocyte colony-stimulating factor,rhG-CSF)治疗小鼠结肠炎的疗效并探讨其可能的作用机制.方法:应用5%2,4,6-三硝基苯磺酸灌肠诱导Balb/c小鼠结肠炎症,结肠炎小鼠随机分为2组,在造模后3 h,分别给予rhG-CSF或磷酸盐缓冲液(phosphate buffered saline,PBS)皮下注射进行治疗干预,连续6 d,每日观察小鼠体质量,腹泻及便血情况.造模后第6天处死小鼠,获取结肠组织,根据黏连、溃疡及炎症计大体损伤评分;取降结肠组织,HE染色后计病理组织评分;获取结肠组织匀浆,应用ELISA方法检测炎症细胞因子白介素-17(interleukin-17,IL-17)及IL-23的表达水平;获取肠系膜淋巴结淋巴细胞,体外培养3 d后,应用流式细胞术检测CD4+CD25+调节性T细胞的表达.结果:rhG-CSF治疗组小鼠的DAI评分、大体损伤评分及病理组织评分明显低于PBS对照组;与对照组相比rhG-CSF治疗组小鼠结肠组织中IL-17及IL-23的表达水平明显减低,而肠系膜淋巴结中CD4+CD25+调节性T细胞的表达上调.结论:基因重组人粒细胞集落刺激因子改善了小鼠的结肠炎症,Th17细胞与调节性T细胞的平衡调节是其可能的作用机制.

AIM： To examine if recombinant human granu- locyte colony-stimulating factor （rhG-CSF） could promote the recovery of 2,4,6-trinitrobenzene sul- furic acid （TNBS）-induced colitis in Balb/c mice and to analyze the potential mechanisms involved. METHODS： Colitis was induced in Balb/c miceby rectal administration of 5%TNBS. Three hours later, the mice were given rhG-CSF （100 μg/kg） or phosphate-buffered saline （PBS） sub- cutaneously once a day from day 0 to day 5. The weight loss, stool, and fecal occult blood were then recorded daily. The mice were sacrificed on day 5, and the whole colons were obtained and scored for adhesion, ulcer and inflammation. Tissue specimens from the descending colon were obtained and stained with hematoxylin and eosin. Inflammation was scored for severity, extent, epithelial damage and crypt loss. The ex- pression of pro-inflammatory cytokine proteins IL-17 and IL-23 in colon tissues was detected by ELISA. Mesenteric lymph node （MLN） cells were prepared and cultured in vitro for 3 d to examine the expression of CD4^＋ CD25^＋ Tregs by flow cytometry. RESULTS： Treatment with rhG-CSF signifi- cantly ameliorated murine colitis in terms of improved clinical and pathological signs. The levels of IL-17 and IL-23 were significantly lower in the colon tissues of rhG-CSF-treated mice in comparison with controls. The expression of CD4^＋ CD25^＋ Tregs in MLN cells from rhG-CSF- treated mice increased. CONCLUSION： Treatment with rhG-CSF ame- liorates murine TNBS-induced colitis via mecha- nisms possibly associated with the suppression of IL-23/IL-17 and promotion of CD4^＋ CD25^＋ Tregs.