臭氧急性暴露对大鼠血管的损伤及其机制

目的:探索不同浓度臭氧(O3)急性暴露对雄性Wistar大鼠血管的损伤效应和可能的机制。方法:120只雄性Wistar大鼠随机分为6组,每组20只;实验动物置于气体染毒柜中,对照组暴露于过滤后空气,处理组分别暴露于浓度为0.12ppm,0.5ppm,1.0ppm,2.0ppm和4.0ppm的臭氧,持续暴露4h。利用PC-lab医学生理信号采集系统获得动脉血压数据;血流变指标和血生化指标由天津迪安诊断实验室检测;血清中内皮素(ET-1)、同型半胱氨酸(HCY)、血管性血友病因子(vWF)、8-羟基脱氧鸟苷(8-OhdG)、白介素(IL-6)和肿瘤坏死因子α(TNF-α)采用酶联免疫(ELISA)微孔板法检测;氧化应激指标超氧化物歧化酶(SOD)活力和丙二醛(MDA)分别采用黄嘌呤氧化酶法、硫代巴比妥酸(TBA)法测定,还原型谷胱甘肽(GSH)和一氧化氮(NO)采用微孔板比色法;取胸主动脉组织制备石蜡切片,经HE染色后观察血管结构改变。结果:0.12ppm臭氧急性暴露可导致动脉收缩血压(SBP)显著升高;不同浓度臭氧暴露均可导致血浆粘度显著升高,1.0ppm臭氧暴露组血沉(ESR)方程K值显著升高,全血高切相对指数和还原粘度均在臭氧浓度为0.5ppm和4.0ppm时显著降低,而红细胞变形指数在臭氧浓度为0.12ppm、0.5ppm、1.0ppm和2.0ppm时显著升高;急性臭氧暴露可导致总胆固醇含量降低,高密度脂蛋白胆固醇(HDL-C)在0.12ppm臭氧暴露组显著降低;当臭氧浓度高于1.0ppm时还可导致机体出现炎症反应(TNF-α升高)和氧化应激反应(MDA升高、GSH降低);臭氧急性暴露可导致血液中ET-1含量升高,在4.0ppm浓度组具有显著性差异,而HCY水平呈现先降低后升高的趋势,在1.0ppm浓度组达到最高值,胸主动脉未见明显的病理改变。结论:臭氧急性暴露可影响大鼠的动脉血压、血流变及胆固醇代谢,可能的机制是臭氧暴露导致炎症反应和氧化应激反应,引起血管内皮功能损伤,并且随着臭氧暴露浓度升高血管内皮细胞功能损伤越显著。

Injury of rat blood vessels caused by acute ozone exposure and its mechanism

Objective: To investigate the vascular damage effects and possible mechanism of acute exposure to ozone (O₃) in male Wistar rats. Methods: One hundred and twenty male Wistar rats were randomly divided into six groups, 20 in each group. The experimental animals were placed in a gas poisoning cabinet, the control group was exposed to filtered air, and the treatment group was exposed to ozone at concentrations of 0.12 ppm, 0.5 ppm, 1.0 ppm, 2.0 ppm, and 4.0 ppm, respectively, for 4 hours. Arterial blood pressure data were obtained by PC-lab medical physiological signal acquisition system. Blood rheology indicators and blood biochemical indicators were detected by Tianjin Dean Diagnostic Laboratory. Serum endothelin-1 (ET-1), homocysteine (HCY), von Willebrand factor (vWF), 8-hydroxydeoxyguanosine (8-OhdG), interleukin (IL-6) and tumor necrosis factor alpha (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA) microplate assay. Oxidative stress indicators superoxide dismutase (SOD) activity and malondialdehyde (MDA) were determined by xanthine oxidase method, thiobarbituric acid (TBA) method, reduced glutathione (GSH) and nitric oxide (NO) were tested by using microplate colorimetry. Paraffin sections were prepared from thoracic aorta tissue, and vascular structure was observed by HE staining. Results: Acute exposure to 0.12 ppm ozone could cause a significant increase in arterial systolic blood pressure (SBP). Exposure to different concentrations of ozone could cause a significant increase in plasma viscosity, and the K value of the ESR equation was significantly increased in the 1.0 ppm ozone exposure group. Both the relative and reduced viscosities were significantly reduced at ozone concentrations of 0.5 ppm and 4.0 ppm, while the red blood cell deformation index was increased significantly at ozone concentrations of 0.12 ppm, 0.5 ppm, 1.0 ppm, and 2.0 ppm. Acute ozone exposure resulted in the decrease of total cholesterol content. The content of high-density lipoprotein cholesterol (HDL-C) was significantly reduced in the 0.12 ppm ozone exposure group. When the ozone concentration was higher than 1.0 ppm, the body may also had an inflammatory reaction (increased TNF-α) and oxidative stress (increased MDA, decreased GSH). Acute exposure to ozone could lead to elevated levels of ET-1 in the blood, with significant differences in the 4.0 ppm concentration group, while HCY levels were decreased firstly and then increased, reaching the highest in the 1.0 ppm concentration group. No obvious pathological changes were observed in the thoracic aorta. Conclusion: Acute ozone exposure can affect arterial blood pressure, blood rheology and cholesterol metabolism in rats. The possible mechanism is that ozone exposure leads to inflammatory reaction and oxidative stress reaction, causing vascular endothelial function damage, and vascular endothelial cells increase with ozone exposure concentration.