The Study Of The Protective Effects Of Sildenafil On Isolated-lung Of Rat During Ischemia-reperfusion

Objective To investigate the protective effects of sildenafil on isolated-lung of rat during ischemia-reperfusion,and explore its possible mechanism.Methods Thirty six male rats were randomly divided into three groups:the nomal saline group,the control group and the trail group.In the nomal saline group,the ex vivo lung blocks were flushed with and stored in the nomal saline. The ex vivo lung blocks were flushed with and stored in Perfadex solution( low-postasssium-dextron solution) in the control group,but in the trail group Perfadex solution containing sildenafil(0.7 mg/L) [1]was used.The lung were stored at 4℃for 8h in all groups.The isolated rat lung reperfusion models were established and the lungs were perfused for 1 h.PaO2 (blood of left atria)were measured at every 15 min intervals during reperfusion.After reperfusion,the lung tissue wet-to-dry (W/D)ratio , myeloperoxidase(MPO), malondialdehyde(MDA) and nitric oxide(NO) activity were obtained.Light microscopic and ultrastructural changes were also examined.Results The levels of decreased PaO2 in three groups were decreased at the every interval time in the samples after reperfusion , the result have a statistical significance (P<0.01/P<0.05),but it were lowest in the nomal saline group than in the control group and the trail group (P<0.05).After reperfusion the W/D ,MDA and MPO were higher in the nomal saline group(P<0 . 05),NO was lower evidently than in the other groups(P<0.01/P<0.05).In the trail group the W/D and MPO were lower than in the control group(P<0.05),but NO increased evidently after reperfusion.The results of MDA did not exit statistical difference between the control and the trial groups. After reperfusion the lung tissue were damaged severely in the nomal saline group,the morphologic and ultrastructual damages in trail group were milder than in control group.Conclusion Sildenafil can alleviate the ischemia—reperfusion injury of lung and improve the protective effect of lung preservation:①After reperfusion ,the oxygenate function of isolated-lung of rat decreased obviously。②Perfadex solution preserve the ex vivo lung perfectly,and sildenafil can improve the protective effects。③Sildenafil protect the lung cells owing to dilating blood vessels,increasing NO, alleviating leucocyte- assemble and oxyradical damage probably。...