大气细颗粒物水溶成分对大鼠胸主动脉舒缩功能的影响

目的探讨大气细颗粒物(PM2.5,)水溶成分静脉染毒后1、6 h,对大鼠胸主动脉血管环收缩、舒张功能的影响.方法 雄性Wistar大鼠30只,分为空白对照组、1 h对照组、6 h对照组、染毒1 h组、染毒6 h组,每组6只.染毒组以PM2.5水溶成分(1 ml/kg)尾静脉注射1、6 h后,分别以25%乌拉坦腹腔注射(0.4 ml/100 g)麻醉后,迅速开胸取大鼠胸主动脉,制备血管环,置于张力换能器进行实验.1 h,6 h对照组以0.9%氯化钠注射液(1 ml/kg)尾静脉注射,处理同染毒组.结果 空白对照组、1 h对照组、6 h对照组三组间血管环舒缩反应差别无统计学意义.染毒1 h后,胸主动脉血管环对60 mmol/L KCi的收缩反应减弱,6 h后有升高趋势,但仍低于对照组.10-6mol/L去甲肾上腺素(NE)预收缩的血管环:乙酰胆碱(ACh)浓度在10-5moL/L、10-7moL/L水平,染毒后1 h舒张率降低.ACh浓度在10-5～10-7mol/L水平,染毒6 h组舒张率较染毒1 h组升高;硝普钠(SNP)浓度在10-5～10-9mol/L水平,染毒后1 h舒张率降低,在10-6mol/L、10-9mol/L水平,染毒后6 h组舒张率较染毒1 h组升高,在10-5～10-7moL/L水平,染毒6 h组舒张率仍低于对照组.结论 PM2.5水溶成分静脉染毒1 h后引起血管收缩抑制、舒张下降,6 h后该作用减弱.

The comparison study on effects of water-soluble components of fine particulate matter on vasomotor function in aortas from rats after exposure in different time

Objective To compare the difference of vasomotor functions in aortas segments from Wistar rats between 1-hour and 6-hours after exposure of water-soluble components of fine particulate matter (PM2.5 ). Methods All 30 Wistar rats were assigned to five groups (n = 6 for each group) at random: the blank control group,control group for 1-hour and 6-hours, exposure group for 1-hour and 6-hours. The rats were sacrificed 1-hour or 6-hours later and aorta ring segments were mounted on wire myographs. Results ( 1 ) There was no significant difference in vasomotor functions among three control groups( P 0. 05 ). (2) 1-hour or 6-hours after exposure there was a decrease of contraction elicited by 60 mmol/L KCl in contrast to the control group(P<0. 05), whereas no significant change between the exposure group for 1-hour and 6-hours (P 0. 05). (3)On the level of 10-5 or 10-7 mol/L, 1-hour after exposure there was a decrease in endothelium-depondent acetylcholine(ACh) elcited relaxation precontracted by 10-6mol/L NE compared with the control group (P <0. 01 or P <0. 05), on the level from 10 -5 to 10-7 mol/L there was a decrease compared with the exposure group for 6-hours ( P < 0. 05 ), whereas no difference between the exposure group for 6-hours and the control group( P 0. 05). On the level from 10-5 to 10-9 mol/L, 1-hour after exposure there was a decrease in endothelium-independent sodium nitroprusside (SNP)elicited relaxation precontracted by 10-6 mol/L NE as compared with the control group( P < 0. 01 or P < 0. 05 )and a decrease on the level of 10-6or 10 -9 mol/L compared with the exposure group for 6-hours ( P < 0. 05 ), 6-hours after exposure a decrease was caused as compared with the control group on the level from 10-5 to 10-7 mol/L (P <0. 01 or P < 0. 05 ). Conclusions Inhibition of contraction and impairment of relaxation in aortas should be caused 1-hour after exposure to water-soluble components of PM2.5 in the air, which is weaken 6-hours after exposure.