小剂量地塞米松对脓毒症小鼠CD11b^+ Gr-1^+髓源抑制性细胞的影响

Effect of low dose of dexamethasone on CD11b^+ Gr-1^+ myeloid-derived suppressor cells in septic mice

目的:观察小剂量地塞米松对脂多糖(LPS)诱导的脓毒症小鼠CD11b+Gr-1+髓源抑制性细胞(MDSCs)的影响。方法:将145只BALB/c雄性小鼠随机分成正常对照组(NC组)35只,脓毒症组(SE组)和小剂量地塞米松干预组(SD组)各55只;SE组和SD组腹腔注射LPS 10 mg/kg制备脓毒症小鼠模型,NC组腹腔注射等量0.9%氯化钠注射液。SD组于注射LPS 2 h后经尾静脉注入地塞米松0.3 mg/kg,SE组和NC组经尾静脉注入等量0.9%氯化钠注射液。注射LPS后时刻记为0 h,于6、12、24 h检测血清干扰素-γ及白细胞介素-10水平,于12、24、48、72 h检测小鼠脾脏及骨髓中CD11b+Gr-1+MDSCs的百分比。结果:与NC组比较,SD组及SE组在实验6 h干扰素-γ和12 h白细胞介素-10水平均增加(P<0.05~P<0.01);SD组与SE组差异亦有统计学意义(P<0.05)。与NC组比较,SE组脾脏MDSCs百分比在12~72 h均明显升高(P<0.01),SD组在12~48 h亦均升高(P<0.01);而SE组和SD组在24~72 h差异亦均有统计学意义(P<0.01)。与NC组比较,SE组和SD组骨髓MDSCs百分比在48 h和72 h均升高(P<0.05~P<0.01);而SE组和SD组在48 h和72 h差异亦均有统计学意义(P<0.05和P<0.01)。结论:小剂量地塞米松可抑制LPS诱导的脓毒症小鼠MDSCs的产生及聚集。

Objective：To investigate the effects of low dose of dexamethasone on CD11b＋ Gr-1 ＋ myeloid-derived suppressor cells （ MDSCs） in septic mice induced by lipopolysaccharide（ LPS） . Methods：The septic mice model was established by the intraperitoneal injection of LPS in BALB/c mice. The mice were randomly divided into the normal control group（ NC group） ,sepsis group（ SE group） and sepsis combined with dexamethasone group（SD group）. The levels of serum interferon-γ and interleukin-10 were detected at 6,12 and 24 hours. The percentage of CD11b＋ Gr-1 ＋ MDSCs in spleen and bone marrow of mice were detected at 12,24,48 and 72 hours. Results：Compared with the NC group,the levels of interferon-γ at 6 hours and interleukin-10 at 12 hours in SE group and SD group increased significantly（P 〈0. 05 to P 〈0. 01）,and the difference of which between SE group and SD group was not statistically different（ P〈0. 05）. Compared with the NC group,the percentages of MDSCs in spleen at 12 to 72 hours in SE group and at 12 to 48 hours in SD group increased significantly（ P〈0. 01）,and the differences of the percentage of MDSCs at 24 to 72 hours between SE group and SD group were statistically different（ P〈0. 05）. Compared with the NC group,the percentages of MDSCs in bone marrow of SE and SD group increased significantly at 48 hours and 72 hours（ P〈0. 05 to P〈0. 01）. the differences of which at 48 and 72 hours between SE and SD groups were statistically significant（P〈0. 05 and P〈0. 01）. Conclusions：Low dose of dexamethasone can inhibit the production and accumulation of MDSCs in septic mice induced by LPS.