氯沙坦对犬体外循环肺损伤的影响

目的：研究氯沙坦对体外循环（ CPB）致犬肺损伤的影响,探讨CPB致肺损伤的机制。方法：健康成年杂种犬12只,体质量（14.25±1.60）kg,雌雄不拘,采用随机数字表法分为对照组（C组）和氯沙坦组（L组）各6只。麻醉后开胸建立CPB模型。 L组于CPB前30 min经股静脉注射氯沙坦1 mg/kg,C组于同时点注射等容量0.9%氯化钠注射液。分别于 CPB前（ T1）、主动脉阻断后45 min（ T2）、主动脉开放后30 min（ T3）、开放后60 min即停机时（ T4）取静脉血测血管紧张素Ⅱ（ AngⅡ）和丙二醛（MDA）水平；取动脉血测血气并计算T1、T4时的氧合指数（OI）和呼吸指数（RI）；光镜下观察肺组织病理学改变。结果：与T1时比较,2组T2~4时血浆AngⅡ和MDA水平均明显升高（P〈0.01）,T4时OI降低、RI升高（P〈0.05~P〈0.01）。L组CPB后各时点血浆AngⅡ水平与C组差异均无统计学意义（P〉0.05）,但L组T4时血浆MDA水平显著低于C组（P〈0.01）。 L组T4时OI和RI与C组差异均无统计学意义（P〉0.05）,但肺损伤较C组减轻。结论：氯沙坦可阻断AngⅡ的作用,抑制氧化应激,可减轻CPB后肺损伤。

Effect of losartan on lung injury during cardiopulmonary bypass in dogs

Objective：To study the effects of losartan on lung injury during cardiopulmonary bypass （ CPB ） in dogs, and its mechanism. Methods：Twelve adult healthy mongrel dogs,weighing（14. 25 ± 1. 60） kg,were randomly divided into the control group （group C,n=6） and losartan group（group L,n=6）. The CPB model of dog was established. The group L and C were intravenously injected with 1 mg/kg of losartan and 0. 9% sodium chloride at 30 min before CPB,respectively. The plasma levels of angiotensinⅡ（ AngⅡ） and malondialdehyde（ MDA） in two groups were measured before injecting（ T1 ） ,at 45 min after aortic cross-clamping（ T2 ） , and at 30 min（ T3 ） and 60 min（ T4 ） after aortic unclamping. The oxygenation index（ OI） and respiratory index（ RI） were calculated at T1 and T4 ,and their lung tissue structures were observed under optical microscope. Results：Compared with T1 ,the plasma levels of AngⅡand MDA in two groups at T2-4 increased significantly（P〈0. 01）,and the OI and RI at T4 in two groups decreased and increased, respectively（P〈0. 05-P〈0. 01）. The differences of the plasma levels of AngⅡ in all time points between Group L and C were not statistical significance（P〉0. 05）. At T4,the level of MDA in group L was significantly lower than that in group C（P〈0. 01）. The differences of the OI and RI at T4 between two groups were not statistical significance（P〉0. 05）,and the lung injury in group L was lighter than that in group C at T4 . Conclusions：Losartan can block the role of AngⅡ,and restrain oxidative stress,which can prevent the lung injury caused by CPB.