RESUMO
Objective To observe the effects of ischemic postconditioning (I-postC) on lung injury after limb ischemia reperfusion (LIR) in rats, and to investigate the protective effect and the mechanisms. Methods Twenty-four Wistar rats were divided into three groups:control group (group Control), ischemia-reperfusion group (group IR) and ischemic postcondi?tioning group (group I-postC). Referring to routine method in our department, the model rats underwent 4-hour ischemia and 4-hour reperfusion of hind limbs were made. In group Control, the rubber band around the limb was loose,which did not block the blood flow. Rats in group I-postC were given repeated 3 times of 5 min ischemia-5 min reperfusion, and then did perfusion 4 h before reperfusion. The blood and lung samples were collected for detecting arterial gas of partial pressure of oxygen [p(O2)] and partial pressure of carbon dioxide [p(CO2)]. The plasma and lung tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD) and xanthine oxidase (XOD) were detected. The morphological changes of lung tissue were ob?served under light microscope and electron microscope. Results It was found that after suffering from ischemia-reperfu?sion, levels of p(O2) and p(CO2) decreased significantly. The activity of SOD in plasma and lung tissues decreased, but XOD and MDA increased significantly (P<0.05). With microscope, lung interstitial vascular dilation, infiltration of neutrophils, the width of the alveolar space, alveolar septal thickening and alveolar exudate were found. Compared with IR group, it was found that p(O2) and p(CO2) increased significantly in group I-postC. The activity of SOD in plasma and lung tissues in?creased, but XOD and MDA decreased significantly(P<0.05). The mild damage of pathological changes were found. Conclu?sion Ischemic postconditioning can reduce the lung injury after limb ischemia reperfusion in rats, which may be related to the inhibition of lipid peroxidation.
