臭氧和细颗粒物暴露对大鼠心脏自主神经系统和系统炎症的影响

目的探讨臭氧(O3)和大气细颗粒物(PM2.5)暴露对大鼠心脏自主神经系统和系统炎症的影响以及二者之间是否存在关联。方法 48只Wistar大鼠随机分为8组。PM2.5低、中、高剂量单独暴露组为每只动物分别经气管滴注0.2、0.8和3.2mg的细颗粒物。O3和PM2.5联合暴露低、中、高剂量组为大鼠预先暴露于0.8ppm的臭氧4h,然后再气管滴注PM2.50.2、0.8和3.2mg。O3单独暴露组为只吸入暴露4h臭氧,对照组为气管滴注生理盐水,每周暴露2次,共3周。末次暴露24h后,测定血压,同时记录心电图。测定血清中TNF-α、IL-6和CRP。取右心室进行HE染色病理分析。结果 PM2.5单独暴露和联合暴露组中心率变异性(HRV)指标与对照组比较有显著变化。O3单独暴露仅引起低频成分(LF)显著增加。心率只有在联合暴露组有明显降低。血压在联合暴露组和高剂量PM2.5组有明显上升。TNF-α和IL-6在PM2.5单独暴露和联合暴露组均有上升趋势。CRP在PM2.5单独和联合暴露组均表现出明显的剂量-效应关系。IL-6、TNF-α和CRP与HRV之间显著相关。病理学检查发现,PM2.5暴露组有颗粒物的沉积和心肌炎症。结论 O3可增强由PM2.5暴露引起的大鼠心脏自主神经系统紊乱和炎症反应。

Effects of ozone and fine particulate matter (PM2.5) on rat cardiac autonomic nervous system and systemic inflammation

Objective To study the effects of ozone and fine particulate matter(PM2.5) on rat cardiac autonomic nervous system and systemic inflammation and the interconnected relationship of these two pathways.Methods 48 Wistar rats were randomly assigned to 8 groups(n=6).Rats were intratracheal instillation of 0.2,0.8 and 3.2 mg/rat PM2.5 as low-dose,medium-dose and high-dose PM2.5 alone exposure groups.Ozone combined PM2.5 groups were exposed to 0.8ppm ozone 4 hours and then instilled 0.2,0.8 and 3.2 mg/rat PM2.5 separately.Rats only inhaled 0.8ppm ozone for 4hours as ozone alone exposure group.Control rats were instilled with saline.Each exposure protocol applied twice a week for three continuous weeks.Systolic blood pressure and electrocardiograph(ECG) morphology of rats were recorded at 24 hours post-exposure of the last exposure.Serum TNF-α,IL-6 and CRP were analyzed.Right ventricles were used as pathological examination with HE staining.Results HRV indices in PM2.5 alone and combined exposure groups showed significant difference compared to control.However,heart rate only reduced significantly in ozone combined PM2.5 groups.Blood pressure rose significantly in combined groups and high-dose PM2.5alone exposure.TNF-αand IL-6 increased significantly in PM2.5alone/and ozone groups.CRP showed obvious dose-dependent relationship in PM2.5 alone and combined groups.Cardiac histopathology results revealed that PM2.5 deposition and myocardial inflammation were also observed in high-dose PM2.5 rats.Conclusion Ozone can enhance the cardiac autonomic nervous system and systemic inflammation induced by PM2.5.