OBJECTIVETo investigate the protective role of ischemic preconditioning (IPC) during lung ischemia-reperfusion (I/R) injury and its influence on inflammatory cytokine production.

METHODSIn vivo I/R injury of rabbit was induced by blocking hilum of the left lung. The wet/dry ratio of the lung, lung permeability index and neutrophils percentage in bronchoalveolar lavage fluid (BALF) were detected as indexes of the lung injury. Serum levels of tumor necrosis factor alpha (TNFalpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) were also detected using enzyme-linked immunosorbent assay. The protective role of IPC and its influence on inflammatory cytokine production were observed.

RESULTSThe wet/dry ratio of the lung, lung permeability index and neutrophils percentage in BALF of I/R group were 9.73 +/- 1.14, (41.62 +/- 5.77) x 10(-4) and (58.1 +/- 10.0)% respectively. The IPC group indexes were 6.23 +/- 0.69, (20.31 +/- 4.03) x 10(-4) and (23.8 +/- 5.2)% respectively. There was a significant difference between the two groups (P < 0.01). Serum levels of TNFalpha, IL-6 and IL-8 of I/R group were (0.9078 +/- 0.1062), (0.2137 +/- 0.0598) and (0.7211 +/- 0.0979) ng/ml respectively. The IPC group indexes were (0.7478 +/- 0.0843), (0.1271 +/- 0.0089) and (0.5903 +/- 0.0746) ng/ml respectively, significantly lower than that of I/R group (P < 0.01).

CONCLUSIONSLung IPC has a marked protection effect against I/R injury. The effect was related to its inhibition of inflammatory cytokines such as TNFalpha, IL-6 and IL-8, thus reducing activation and infiltration of neutrophils.