不同浓度大气细颗粒污染物PM2.5对心脏组织功能的影响

Effects of different concentrations of airborne fine particulate matter 2.5 on heart tissue function

目的探讨空气动力学直径小于2.5μm的颗粒(PM2.5)对大鼠心血管系统的影响及PM2.5影响心脏功能的机制。方法在重庆市区采集PM2.5,选取雄性Wistar大鼠40只作为研究对象,设置正常对照组和实验染毒组[包括PM2.5低浓度组(1.0 mg/0.25 m L)、PM2.5中浓度组(3.0 mg/0.25 m L)、PM2.5高浓度组(8.0 mg/0.25 m L)]每组10只。采用气管滴注法进行PM2.5染毒,观察各组大鼠心肌组织结构、血清心肌肌钙蛋白T(cTnT)水平,同时检测心肌白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平,分析机体肺灌注PM2.5后心血管系统的炎性反应和心脏功能变化。结果大鼠PM2.5染毒后,不同浓度实验染毒组大鼠心肌细胞水肿程度加深,心肌纤维呈波浪状排列,形态异常;实验染毒组大鼠血清cTnT水平明显高于正常对照组,且与PM2.5浓度呈正相关(P<0.05),PM2.5高浓度组大鼠cTnT水平明显高于PM2.5中、低浓度组,但PM2.5中、低浓度组大鼠cTnT水平无明显差异。实验染毒组大鼠心肌组织IL-6、TNF-α水平较正常对照组明显升高,差异有统计学意义(P<0.05),且与PM2.5浓度有关。结论 PM2.5引起Wistar大鼠心脏组织结构损伤,心血管系统出现明显的炎性反应,大鼠心脏功能出现损伤,提示PM2.5可能通过炎性反应损伤机体心血管系统,雾霾可能是诱发心血管疾病的重要原因。

Objective To study the effects of particles of diameter less than μm2.5 （PM2.5） in aerodynamics on the cardiovascular system, and to analyze the mechanism of PM2.5 affecting the heart function. Methods PM2.5 in Chongqing urban region was collected. Forty male Wistar rats were selected as the research subjects and divided into the normal control group and experimental contamination groups[including low concentration PM2.5 group （1.0 mg/0.25 mL）,medium concentration PM2.5 group （3.0 mg/0.25 mL）, high concentration PM2.5 group （8.0 rag/0.25 mL）, 10 cases in each group]. The intratraeheal instillation method was adopted to conduct the PM2.5 contamination. The rat myocardial tissue structures and serum cTnT level in each group were observed. Meanwhile IL-6 and TNF-α expression levels were detected. The inflammatory reaction of cardiovascular system and cardiac function change were observed after PM2.5 pulmonary perfusion. Results The eardiomyocyte edema degree in each experimental contamination group with different concentrations was deepened, the myocardial fibers had wavy arrangement with morphologic abnormality after PM2.5 contamination;the rat serum cTnT level in the experimental contamination group was significantly higher than that in the normal control group ,moreover which was positively correlated with PM2.5 concentration（P〈0.05 ）, the rat cTnT level in the high PM2.5 concentration group was significantly higher than that in the medium PM2.5 concentration group and low PM2.5 concentration group, but which had no obvious difference between the medium PM2.5 concentration group and low PM2.5 concentration group. The rat myocardial tissue IL-6 and TNF-α expression levels in the experimental contamination groups were significantly increased compared with the normal control group,the difference was statistically significant （P〈0.05）, moreover which were correlated with PM2.5 concentration. Conclusion PM2.5 causes the injury of rat heart tissue structure,inflammatory reactions of cardiovascular system and injure of myocardial function,prompting that PM2.5 may injure the cardiovascular system by the inflammatory reactions. Haze may be an important cause inducing cardiovascular diseases.