CD4+ CD25+ T细胞在脂多糖诱导多器官功能障碍综合征小鼠中的保护作用研究

摘要

目的：探索CD4+CD25+ T细胞在脂多糖( lipopolysaccharide, LPS)诱导的多器官功能障碍综合征( mul-tiple organ dysfunction syndrome, MODS)小鼠中的作用。方法选择雄性BALB/c小鼠,以LPS 9.0 mg/kg腹腔注射制备小鼠MODS模型作为建模组(60只),对照组小鼠(10只)同法注射0.9%氯化钠注射液,应用流式细胞术在第2、5天分别检测两组小鼠体内CD4+CD25+ T细胞水平；选择180只小鼠,于-2 d分别腹腔注射磷酸盐缓冲液、IgG1及200μg Anti-CD25 mAb,再于0 d注射LPS分别建立LPS组、IgG1+LPS组和Anti-CD25 mAb+LPS组小鼠模型,每组60只,计算各组CD4+CD25+ T细胞百分比,并取各组小鼠肺脏组织行HE染色,观察组织细胞学改变；再建立LPS组小鼠54只,IgG1+LPS组小鼠34只,Anti-CD25 mAb+LPS组小鼠32只,观察3组小鼠的生存率。结果建模组小鼠CD4+CD25+ T细胞比例与对照组相比,在2 d时下降(t=2.873, P=0.006),在5 d时上升(t=2.963,P=0．004)。Anti-CD25 mAb+LPS组注射LPS后2 d、5 d CD4+CD25+ T细胞比例均下降,与其余两组比较差异均有统计学意义( P均<0.01)。肺组织HE染色结果提示中和CD4+CD25+ T细胞会加重LPS诱导MODS小鼠的肺部损伤,并增加小鼠的死亡率。结论 CD4+CD25+ T细胞在LPS诱导的MODS中起保护作用。%Objective To investigate the contribution of the CD4 +CD25 + T cells to the development of multiple or-gan dysfunction syndrome ( MODS) in mice. Methods The male BALB/c mice were used for the experiment. The lipopo-lysaccharide (LPS) was intraperitoneally injected at a dose of 9. 0 mg/kg to induce the MODS model as the experiment group (n=60). For the mice in control group, the same volume of normal saline (0. 9%) was administered intraperitoneally (n=10). The level of CD4 +CD25 + T cells was evaluated in mice at the 2nd day and the 5th day by flow cytometry. And 180 mice were intraperitoneally injected with 200 μg of anti-CD25 mAb, IgG1 or phosphate buffer solution (PBS) at day-2, respective-ly. Two days later (day 0), the mice were intraperitoneally injected with LPS and grouped as LPS, IgG1+LPS and anti-CD25 mAb+LPS respectively (n=60). The percentage of CD4 +CD25 + T cells was calculated eventually and the lung tissue was separated for the histological examination by HE staining. The survival rate was observed following MODS and sample sizes were 54 for LPS, 34 for IgG1+LPS and 32 for anti-CD25 mAb+LPS. Results The number of CD4 +CD25 + T cells in ex-periment group markedly decreased on day 2(t= 2. 873,Ρ= 0. 006), and significantly increased on day 5(t= 2. 963,Ρ=0. 004)when compared with control group. And the CD4 +CD25 + T cells percentage was decreased by injection of LPS in group anti-CD25 mAb+LPS on both day 2 and day 5, there were statistical differences when compared with the other two groups (Ρ<0. 01). Moreover, the HE staining result indicated that neutralization of CD4 +CD25 + T cells profoundly in-creased the degree of lung tissue injury, and it also increased mice mortality. Conclusion CD4+CD25+ T cells are major protective modulators in MODS in mice.