Effect Of Ischemic Post Conditioning On CD4~+ T Cells Activity In Ischemia-Reperfusion Injurious Lung In Rats

Objective:To investigate the effects of ischemic post-conditioning on CD4+T cells expression of ischemia- reperfusion injurious lung in rats and the inflammatory response its possible protective mechanisms.Methods:30 rats were randomly allocated into three groups:①Sham group (n=10): Only Sham operation (thoracotomy) and no ischemia for 180minute.②Ischemia-reperfusion group (IR group):Interruption of pulmonary perfusion and ventilation for 60minute followed by reperfusion for 120minute.③Ischemic post-conditioning group (IPostC group):ischemic post-conditioning (5R/5I, three times) between the end of ischemia and the beginning of reperfusion followed by reperfusion for 90minute. Small pieces of lung tissue and Bronchoalveolar lavage fluid at the end of experiment. The concentration of MPO,IL-17,IL-8 and CD4+T cells were determined respectively. The wet to dry weight ratio (W/D) was also measured at the end of reperfusion. The lung tissue was prepared for light microscopic morphological observation at the end of experiment.Results:The W/D ratio was significantly lower in Sham group (1.103±0.0587) than that in IR group (1.235±0.04249) and IPostC group (1.136±0.04274) (P<0.05). The W/D ratio in IPostC group was also lower than that in IR group (P<0.05). The level of IL-8 in bronchoalveolar lavage fluid became significantly lower in Sham group (20.74±2.375 ng /L) than that in IR group (46.053±4.777 ng/L) and IPostC group (32.54±4.1773ng/L) (P<0.05); IL-8 in bronchoalveolar lavage fluid in IPostC group was also lower than that in IR group (P<0.05).The level of IL-17 in bronchoalveolar lavage fluid became significantly lower in Sham group (43.752±4.828ng/L) than that in IR group (76.867±4.936ng/L) and IPostC group (58.459±3.809ng/L) (P<0.05); IL-17 in bronchoalveolar lavage fluid in IPostC group was also lower than that in IR group (P<0.05); The level of MPO in bronchoalveolar lavage fluid became significantly lower in Sham group (1.328±0.126 u/g) than that in IR group (2.337±0.215 u/g) and IPostC group (1.680±0.169 u/g) (P<0.05); MPO in bronchoalveolar lavage fluid in IPostC group was also lower than that in IR group (P<0.05). The level of IL-8 in lung tissue became significantly lower in Sham group (87.15±4.60) than that in IR group (61.02±6.34) and IPostC group (78.42±4.84) (P<0.05); IL-8 in lung tissue in IPostC group was also lower than that in IR group (P<0.05). The level of IL-17 in lung tissue became significantly lower in Sham group (89.41±4.34) than that in IR group(61.77±6.10) and IPostC group (74.66±4.82) (P<0.05); IL-17 in lung tissue in IPostC group were also lower than that in I/R group (P<0.05); The level of CD4+T cells in lung tissue became significantly lower in Sham group (87.10±3.88) than that in IR group (57.59±5.37) and IPostC group (75.94±4.76) (P<0.05); CD4+T cells in lung tissue in IPostC group was also lower than that in I/R group (P<0.05). The lung histologic examination showed that IR group was significantly more serious than that in Sham group and IPostC group.Conclusions:Ischemic postconditioning can significantly play an impotant role in lung protection by reducing lung ischemia-reperfusion injury and the inflammation response of lung tissue. One of possible mechanisms is that postconditioning inhibits the immunological activity of CD4+ T cells in lung tissue.