M1/M2型巨噬细胞极化参与肾组织炎症损伤和修复进程

M1/M2 macrophage polarization is involved in inflammatory injury and repair process of renal tissues

目的:研究M1/M2型巨噬细胞在肾组织炎症损伤和修复进程中的分布趋势及作用。方法:将45只雄性SD大鼠随机分为缺血再灌注损伤(IRI)组和单侧输尿管梗阻(UUO)组两部分。IRI组分为假手术(sham)组及术后0、6、24和72 h组;UUO组分为sham组及梗阻3、7和14 d组;每个时相5只大鼠。全自动生化分析仪检测血肌酐和尿素氮水平;HE与免疫组织化学染色分别观察肾组织损伤及CD68的表达;流式细胞术检测M1(CD68+、F4/80+和CD16/32+)和M2(CD68+、F4/80+和CD206+)型巨噬细胞的分布;ELISA检测诱导型一氧化氮合酶(i NOS)、精氨酸酶1(Arg-1)、转化生长因子β1(TGF-β1)及肿瘤坏死因子α(TNF-α)水平。结果:IRI早期,肾组织损伤程度随再灌时间延长而加剧,并与CD68+巨噬细胞浸润呈一致性变化趋势;至24 h,组织损伤与巨噬细胞浸润最为严重;但之后随时间延长,损伤和巨噬细胞浸润反而减轻。UUO组中,肾损伤随梗阻时间延长而加剧,14d时纤维化明显;而巨噬细胞浸润第7天最为严重,之后又有减轻。流式细胞术分析显示IRI和UUO损伤早期浸润的巨噬细胞以M1型为主,i NOS表达较高;IRI和UUO损伤后期巨噬细胞均向M2型极化,Arg-1水平明显增加;巨噬细胞这种变化趋势与肾组织在不同时间节点出现损伤与修复表征存在明显相关性。深入分析发现,M1型巨噬细胞可通过诱导TNF-α高表达促进早期炎症损伤,M2型巨噬细胞通过提高TGF-β1水平促进后期纤维增生性修复。结论:UUO和IRI过程中均存在巨噬细胞极化:M1型巨噬细胞可诱导早期损伤,M2型巨噬细胞则参与损伤后期的纤维性修复。M1和M2型巨噬细胞在损伤修复过程中的极化特征可为临床治疗提供指导。

AIM ： To investigate the distribution and mechanism of M1/M2 macrophages in inflammatory injury and repair process of renal tissues. METHODS ： SD male rats （ n =45） were randomly divided into 2 parts ： ischemia- reperfusion injury （IRI） and unilateral ureteral obstruction （UUO） renal injury. The rats with IRI were divided into sham operation group and operation groups （0, 6, 24, and 72 h after operation） , and the rats with UUO were divided into sham operation group and operation groups （3,7 and 14 d after operation）. Automatic biochemical analyzer was used to detect serum levels of creatinine and urea nitrogen. The degree of renal injury in IRI group and UUO group were detected by HE staining. The expression of CD68 was examined by immunohistochemical staining. The levels of inducible nitric oxide syn-thase （iNOS） , arginase-1 （Arg-1） , transforming growth factor-pl （TGF-pl） and tumor necrosis factor-a （TNF-a） were measured by ELISA. The polarizations of Ml （ CD68 ＋ , F4/80＋ and CD16/32＋ ） and M2 （ CD68 ＋ , F4/80＋ and CD206 ＋ ） macrophages were analyzed by flow cytometry. RESULTS： In IRI group, the infiltration of CD68 ＋ macrophages and the degree of injury were increased with the prolongation of time in the renal tissues. At 24 h, the tissue injury and macrophage infiltration were the most serious, but then decreased. At 72 h, the tissue damage and CD68 ＋ macrophage in-filtration were significantly reduced. In UUO group, obstructive injury was increased with the prolongation of time, and at 14 d, marked fibrous hyperplasia occurred. The infiltration of CD68 ＋ macrophages at 7 d was the most serious, but then reduced at 14 d. Flow cytometry analysis showed that Ml macrophages were the majority in the early stages of UUO and IRI, and the result of ELISA identified the higher level of iNOS. At the late stage of injury, the Ml macrophages were de-creased, while the M2 macrophages were increased with higher level of Arg-1. Ml macrophage-mediated early injury was due to the induction of TNF-a expression, and M2 macrophage-mediated later recovery was due to enhancing TGF-pl levels. CONCLUSION： The polarization of Ml and M2 macrophages is involved in the processes of UUO and IRI. Ml macrophages play a key role in early injury, and M2 macrophages contribute to the late stage of fibrotic repair. The polari-zation of macrophages during renal injury and repair provides a guiding significance for the clinical treatment.