周细胞微囊泡对脓毒症大鼠肺损伤的保护作用

Pericyte-derived microvesicles protects septic rats against lung injury

目的探讨周细胞(pericyte,PC)分泌的微囊泡(microvesicle,MV)对脓毒症大鼠肺损伤的保护作用。方法利用差速离心法提取周细胞微囊泡(PC derived MV,PC-MV),并采用透射电镜和流式细胞仪进行鉴定。将40只SD大鼠(雌雄不拘,12~14周龄,体质量约220 g)按随机数字表法分为4组(n=10):正常组、PC-MV对照组(正常小鼠尾静脉注射PC-MV,1×10^(7)/只)、脓毒症组[使用盲肠结扎穿孔术(cecal ligation puncture,CLP)复制大鼠脓毒症模型]和PC-MV治疗组(脓毒症模型大鼠尾静脉注射PC-MV,1×10^(7)/只)。检测大鼠的肺湿干质量比和肺组织伊文思蓝渗出量,观察PC-MV对脓毒症大鼠肺血管通透性的作用;制备肺病理切片并检测动脉血气指标,观察PC-MV对肺组织功能的作用;检测大鼠血清炎性因子水平,观察PC-MV对脓毒症炎症反应的作用。结果与正常组相比,脓毒症组大鼠肺功能明显受损,表现为肺组织结构破坏,大量红细胞及炎性细胞渗出,动脉血氧分压(PaO_(2))下降33.6%,动脉血二氧化碳分压(PaCO_(2))升高47.5%;脓毒症大鼠肺血管通透性显著增加,表现为肺湿干质量比增加,肺对伊文思蓝透过率增加;脓毒症大鼠炎性因子TNF-α、IL-6水平升高(P<0.01)。输注外源性PC-MV可改善肺病理结构,恢复动脉血气(与正常组相比,PC-MV治疗组PaO_(2)下降17.7%,PaCO_(2)升高26.9%),减轻炎性因子渗出(与脓毒症组相比,PC-MV治疗组炎性因子TNF-α水平下降10.7%,IL-6水平下降23.9%),显著保护脓毒症大鼠肺功能。同时PC-MV可减轻脓毒症后肺血管渗漏,对肺血管通透性有明显的保护作用。结论PC-MV对脓毒症大鼠肺损伤有明显的保护作用。

Objective To investigate the protective effect of pericyte (PC)-derived microvesicle (MV) on lung injury in septic rats. Methods PC-MV was harvested by differential centrifugation and identified by transmission electron microscopy (TEM) and flow cytometry (FCM). Forty SD rats of either sex (12~14 weeks old, about 220 g) were randomly divided into 4 groups (n=10): normal group, PC-MV control group (normal rats with PC-MV injection), sepsis group (cecal ligation puncture, CLP), and PC-MV treatment group(septic rats with PC-MV injection). The effects of PC-MV (1×10^(7) per rat) on pulmonary vascular permeability in septic rats were observed by measuring the wet/dry weight ratio of lung and Evans blue dye exudation in lung tissue, those on pulmonary tissue function were determined by lung pathological sections and arterial blood gas analysis, and those on inflammation were observed by detecting the levels of inflammatory factors. Results Compared with the normal group, the pulmonary function was obviously impaired in the septic rats, which was manifested as destruction of lung tissue structure, exudation of a large number of red blood cells and inflammatory cells, and decrease of oxygen partial pressure (PaO_(2), 33.6%) and increase of carbon dioxide partial pressure in the arteries (PaCO_(2), 47.5%). In septic rats, pulmonary vascular permeability was significantly increased, which was manifested as increment of lung wet/dry weight ratio, increment of Evans blue permeability in the lung, and increased levels of TNF-α and IL-6 (P < 0.01). Exogenous PC-MV improved pulmonary structure, restored the arterial blood gas (compared with the normal group, PaO_(2): decreased by 17.7%;PaCO_(2): increased by 26.9%), reduced inflammatory factor exfiltration (compared with the sepsis group, TNF-α level: decreased by 10.7%;IL-6 level: decreased by 23.9%) in PC-MV treatment group when compared with the sepsis group), and significantly protected pulmonary function of septic rats. Conclusion PC-MV has a protective effect on lung injury in septic rats.