髓源性抑制细胞通过抑制炎症反应减轻小鼠肾脏缺血再灌注损伤

Myeloid-derived suppressor cells alleviate renal ischemia-reperfusion injury in mice by inhibiting inflammatory response

目的:探讨髓源性抑制细胞(MDSC)对小鼠肾脏缺血再灌注损伤(IRI)的作用及其可能机制。方法:15只雄性C57BL/6小鼠分为假手术组、IRI组、IRI+MDSC组,每组5只。所有小鼠采取背部双侧切口,切除左肾。假手术组小鼠暴露右肾50 min后缝合,IRI组夹闭右侧肾蒂50 min后开放灌注,IRI+MDSC组于开放灌注1 h内经尾静脉输注使用C57BL/6小鼠骨髓细胞诱导的MDSC。恢复灌注后24h,留取小鼠血液及肾脏和脾脏组织标本,观察肾组织病理变化,检测血尿素氮和肌酐水平。ELISA检测血清中细胞因子TNF-α、IFN-γ、IL-6和IL-10水平。流式细胞术检测脾脏中T细胞活化。符合正态分布的计量数据以均数±标准差(±s)表示,采用单因素方差分析比较。结果:与IRI组相比,IRI+MDSC组小鼠肾功能明显改善,血尿素氮和血清肌酐水平均低于IRI组[(29.6±3.1)和(34.1±1.4)mmol/L,(105±13)和(176±20)μmol/L,P均<0.05]。IRI+MDSC组肾小管上皮细胞坏死程度、范围及炎性细胞浸润程度较IRI组减轻,Paller评分优于IRI组[(55.0±3.0)和(40.6±6.7)分,P<0.05]。IRI+MDSC组血清中促炎性细胞因子水平均低于IRI组(P均<0.05),TNF-α分别为(452±55)和(605±73)pg/mL,IFN-γ分别为(405±101)和(576±76)pg/mL,IL-6分别为(459±37)和(863±20)pg/mL;而具有抗炎作用的细胞因子IL-10水平则高于IRI组,分别为(1519±244)和(926±66)pg/mL。同时,IRI+MDSC组小鼠脾脏中活化的CD4+T细胞和CD8+T细胞水平均低于IRI组,分别为(15.6±1.3)%和(20.2±1.4)%、(31.8±1.8)%和(40.4±2.0)%,差异均有统计学意义(P均<0.05)。结论:体外诱导MDSC可通过抑制IRI后机体的炎症反应,减轻肾损伤。

Objective:To investigate the effect and mechanism of myeloid-derived suppressor cells (MDSCs) on renal ischemia-reperfusion injury (IRI) in mice.Methods:A total of 15 male C57BL/6 mice were randomly divided into Sham group (n=5), IRI group (n=5), IRI combined with MDSCs transfusion group (IRI+ MDSC group, n=5). Twenty-four hours after perfusion, blood and kidney tissue samples of mice were collected, and the pathological changes of kidney tissue were observed by hematoxylin-eosin (HE) staining, and the contents of blood urea nitrogen (BUN) and serum creatinine (Cr) were detected. Serum levels of cytokines TNF-α, IFN-γ, IL-6 and IL-10 were detected by ELISA. T-cell activation in spleen was detected by flow cytometry. One-way ANOVA was used to compare the differences between multiple groups.Results:Compared with the IRI group, the IRI+ MDSC group showed significantly improved renal function [Cr: (105±13) and (176±20) μmol/L, BUN: (34.1±1.4) and (29.6±3.1) mmol/L, P<0.05]. The necrosis degree and range of renal tubular epithelial cells and inflammatory cell infiltration degree were reduced in the IRI+ MDSC group. Paller scores were better in the IRI+ MDSC group than those in the IRI group [(55.0±3.0) vs. (40.6±6.7), P<0.05]. Serum levels of pro-inflammatory cytokines [TNF-α: (452±55) vs. (605±73) pg/mL, IFN-γ: (405±101) vs. (576±76) pg/mL, and IL-6: (459±37) vs. (863±20) pg/mL] in the IRI+ MDSC group were lower than those in IRI group (all P<0.05), respectively. However, the level of anti-inflammatory cytokine IL-10 was higher in the IRI+ MDSC group [(1519±244) pg/mL]. At the same time, the levels of activated CD4+ T cells and CD8+ T cells in spleen of the IRI+ MDSC group were lower than those of the IRI group, which were (15.6±1.3)% and (20.2±1.4)%, (31.8±1.8)% and (40.4±2.0)%, respectively, and the differences were statistically significant (all P<0.05).Conclusion:MDSCs induced in vitro can alleviate renal injury by inhibiting the inflammatory response after IRI.