高肺血流量及长期雾化吸入硝酸甘油对肺血管舒张反应的影响

The influence of increased pulmonary blood flow and long course of nebulized inhalation of nitroglycerin on the relaxation activity of rat′s pulmonary arteries

目的 以左向右分流的大鼠为对象 ,观察高肺血流量及长期雾化吸入硝酸甘油 (NTG)对肺血管舒张反应的影响。方法 雄性Wistar大鼠 1 7只 ,分为吸入组 (n =5)、分流组 (n =5)和对照组 (n =7)。分流组和吸入组用手术造成腹主动脉和下腔静脉之间左向右分流。手术后饲养 1 2周 ,开始压力喷射雾化吸入。吸入组吸入NTG ,分流组和对照组吸入生理盐水 ,每日吸一次 ,每次吸 1 0min ,共吸 3周。之后取肺动脉环离体灌流 ,观察其对乙酰胆碱 (Ach)、硝普钠、NTG的舒张反应。结果 与对照组相比 ,吸入组和分流组的肺动脉环对Ach舒张反应明显减弱 (P <0 .0 5) ;三组血管环对硝普钠和NTG舒张反应无明显差别。结论 高肺血流量产生的高切应力损伤了肺动脉对Ach的舒张功能 ,长期雾化吸入NTG没有使之改善。

Objective To study the influence of increased pulmonary blood flow and long course of nebulized inhalation of nitroglycerin on the relaxation activity of rat′s pulmonary arteries. Methods Seventeen male Wistar rats were randomly divided into Neb group;shunt group and control group. An arterial venous shunt was performed between the abdominal aorta and inferior vena cava in rats of Neb and Shunt groups. Twelve weeks after the operation, nebulized nitroglycerin was inhaled by rats in the Neb group using pressurized air ejection mobilization, while nebulized saline was inhaled by rats of the other two groups. Ten minutes inhalation was given each day for each rat. After three weeks of inhalation, the main pulmonary artery of each rat was removed for study. The pulmonary artery′s relaxation activities in response to acetylcholine, nitroprusside and nitroglycerin were measured in vitro. Results The relaxation activity to acetylcholine in both the Neb and Shunt groups was decreased compared to that in the control group (P< 0.05). The relaxation activity to both nitroprusside and nitroglycerin was similar in the three groups. Conclusions The endothelium dependent relaxation to acetylcholine of the rat′s pulmonary artery was impaired because of the increased shear stress resulting from high pulmonary blood flow. Nebulized inhalation of nitroglycerin for 3 weeks did not ameliorate the impairment.