目的:研究空气负离子(NAIs)对血压的影响及其可能的机制。氧化应激,自发性高血压大鼠(SHR)的炎症状态。
方法:将60名SHR(男女各半)随机分为1个月组和3个月组,每组30只大鼠,根据干预的持续时间。每组根据每日干预时间进一步随机分为3组:SHR对照组,2hNAIs-SHR组,和6小时NAIs-SHR组,每组10只大鼠。此外,20WistarKyoto(WKY)(一半是男性,一半是女性),随机分为1个月WKY组和3个月WKY组,每组10只大鼠,根据干预时间。2hNAIs-SHR组和6hNAIs-SHR组每天暴露于NAIs浓度为4.5×10〜4-5×10〜4cm〜3的环境中2h和6h。WKY组和SHR组每天暴露于正常空气中。每三天测量各组大鼠的血压,每周测量一次体重。在饲养的第一个月和第三个月牺牲老鼠后,称量器官的湿重。采用酶联免疫吸附试验(ELISA)检测8-羟基脱氧鸟苷(8-OHdG),白细胞介素-6(IL-6),白细胞介素-8(IL-8),肿瘤坏死因子-α(TNF-α),一氧化氮(NO)和内皮素-1(ET-1)水平。活性氧(ROS)检测试剂盒用于检测ROS水平。丙二醛(MDA)和超氧化物歧化酶(SOD),通过比色分析测量谷胱甘肽(GSH)和谷胱甘肽二硫化物(GSSG)。HE染色观察各组胸主动脉组织病理学形态学改变,Westernblot检测胸主动脉38丝裂原活化蛋白激酶(p38MAPK),细胞外信号调节激酶(ERK),c-Junn端激酶(JNK),c-fos蛋白,c-jun蛋白及其磷酸化蛋白水平。
结果:同周龄组WKY雄性小鼠体重高于SHR对照组,其他各组之间的体重没有显着差异。SHR对照组的心脏系数(4.66±0.48)高于WKY组(3.73±0.15)(P&lt;0.05),虽然大脑系数没有显着差异,肾,组之间的肝和脾。同龄WKY组血压低于SHR组,SHR对照组在2-5周和8-11周的血压高于2hNAIs-SHR和6hNAIs-SHR组(P<0.05)。HE染色显示,内部,2hNAIs-SHR组和6hNAIs-SHR组胸主动脉中膜和外膜较SHR对照组均有不同程度的改善,包括无序的内部膜结构,增厚的中间膜和破碎的外部膜。在氧化应激水平方面,与SHR对照组相比,ROS(0.66%±0.17%,0.49%±0.32%)和8-OHdG((48.29±8.00)ng/mL,6hNAIs-SHR组(33.13±14.67)ng/mL水平较低(P<0.05),而1个月6hNAIs-SHR组GSH/GSSG比值较高(10.08±4.93)。与2hNAIs-SHR组相比,6hNAIs-SHR组ROS水平(0.99%±0.19%)较低(P<0.05)。在炎症因子水平方面,与SHR对照组相比,IL-8水平((160.44±56.54)ng/L,6hNAIs-SHR组(145.77±38.39)ng/L)较低(P&lt;0.05),而1个月WKY组ET-1水平((249.55±16.98)ng/L)较高。各组间NO水平无显著差异。1个月SHR对照组大鼠胸主动脉中p-p38蛋白的相对表达低于WKY组(P<0.05)。SHR对照组3个月时大鼠胸主动脉中p-p38和p-c-fos蛋白的相对表达高于2hNAIs-SHR和6hNAIs-SHR组(P<0.05)。
结论:浓度为4.5×10~4-5×10~4/cm~3的NAIs干预可能通过ROS/MAPK/AP1信号通路调节SHR大鼠的部分氧化和炎症状态。从而降低他们的血压水平。
OBJECTIVE: To investigate the effects and possible mechanisms of negative air ions(NAIs) on blood pressure, oxidative stress, and inflammatory status in spontaneous hypertension rats(SHR).
METHODS: A total of 60 SHR(half male and half female) were randomly divided into one-month and three-month groups, 30 rats per groups, based on the duration of the intervention. Each group was further randomized into three groups based on the daily intervention time: SHR control group, 2 h NAIs-SHR group, and 6 h NAIs-SHR group, 10 rats per groups. In addition, 20 Wistar Kyoto(WKY)(half male and half female), were randomized into one-month WKY group and three-month WKY group, 10 rats per groups, based on the intervention time. The 2 h NAIs-SHR group and 6 h NAIs-SHR group were exposed to an environment with NAIs concentrations of 4.5×10~4-5×10~4 cm~3 per day for 2 h and 6 h. The WKY group and SHR group were exposed to normal air on a daily basis. Blood pressure of rats in each group was measured every three days, while weight was measured once a week. After sacrificing the rats in the first month and the third month of rearing, wet weight of the organs was weighed. The enzyme linked immunosorbent assay(ELISA) was used to detect 8-hydroxylated deoxyguanosine(8-OHdG), interleukin-6(IL-6), interleukin-8(IL-8), tumor necrosis factor-α(TNF-α), nitric oxide(NO) and endothelin-1(ET-1) levels. Reactive oxygen species(ROS) detection kit was used to detect ROS level. Malondialdehyde(MDA) and superoxide dismutase(SOD), glutathione(GSH) and glutathione disulfide(GSSG) were measured by colorimetric analysis. HE staining was conducted to observe the histopathological morphological changes of the thoracic aorta in each group, and Western blot was conducted to detect the thoracic aortap38 mitogen-activated protein kinase(p38 MAPK), extracellular signal-regulated kinases(ERK), c-Jun n-terminal kinase(JNK), c-fos proteins, c-jun proteins and their phosphorylated proteins level.
RESULTS: The weight of WKY male mice in the same week age group was higher than that of SHR control group, and there was no significant difference in the weight between the other groups. The coefficient of heart in SHR control group(4.66±0.48) was higher than that in WKY group(3.73±0.15)(P<0.05), while there were no significant differences in the coefficients of brain, kidney, liver and spleen among the groups. Blood pressure in WKY group at the same age was lower than that in SHR group, and blood pressure in SHR control group at 2-5 and 8-11 weeks was higher than that in 2 h NAIs-SHR and 6 h NAIs-SHR groups(P<0.05). HE staining showed that the internal, middle and external membranes of thoracic aorta in 2 h NAIs-SHR group and 6 h NAIs-SHR group were improved to varying degrees compared with those in SHR control group, including disordered internal membrane structure, thickened middle membrane and broken external membrane. In terms of oxidative stress levels, compared with the SHR control group, the ROS(0.66%±0.17%, 0.49%±0.32%) and 8-OHdG((48.29±8.00) ng/mL, (33.13±14.67)ng/mL) levels were lower in the 6 h NAIs-SHR group(P<0.05), while the GSH/GSSG ratio was higher in the one-month 6 h NAIs-SHR group(10.08±4.93). Compared with the 2 h NAIs-SHR group, the ROS level(0.99%±0.19%) was lower in the 6 h NAIs-SHR group(P<0.05). In terms of inflammatory factor levels, compared with the SHR control group, the IL-8 levels((160.44±56.54) ng/L, (145.77±38.39) ng/L) were lower in the 6 h NAIs-SHR group(P<0.05), while the ET-1 level((249.55±16.98) ng/L) was higher in the one-month WKY group. There was no significant difference in NO levels among the groups. The relative expression of p-p38 protein in the thoracic aorta of rats in the one-month SHR control group was lower than that in the WKY group(P<0.05). The relative expression of p-p38 and p-c-fos proteins in the thoracic aorta of rats at three-months was higher in the SHR control group than in the 2 h NAIs-SHR and 6 h NAIs-SHR groups(P<0.05).
CONCLUSIONS: The intervention of NAIs at a concentration of 4.5×10~4-5×10~4/cm~3 may regulate the partial oxidation and inflammatory state of SHR rats through the ROS/MAPK/AP1 signaling pathway, thereby reducing their blood pressure level.