Expression of heme oxygenase in injured lung following ischemia-reperfusion of limbs in rats / 中国病理生理杂志

ABSTRACT

AIM:To observe the changes in heme oxygenase-1(HO-1) expression in the lung after ischmia-reperfusion of hind limbs in rats.METHODS:Hind limbs ischemia was made by clamping infrarenal aorta with a microvascular clip and lung injury was made by following reperfusion. Lung tissue was obtained from the animals subjected to sham operation, 4 h ischemia without reperfusion and 4 h, 8 h, 16 h, 24 h, 48 h reperfusion following 4 h ischemia. The levels of HO-1 mRNA and protein were measured at different times by Northern blot and Western blot. Immunohistochemistry technique was used to determine the cell types responsible for limb ischemic reperfusion induced HO-1 expression. RESULTS:After ischemia-reperfusion of limbs, HO-1 mRNA increased by 4 h, reached a peak at 16 h, and returned toward baseline at 24-48 h. This time course correlated with increased HO-1 protein. Immunohistochemical studies showed HO-1expressed in a variety of cell types, including the airway epithelium, alveolar macrophages and vascular smooth muscular cells. There were no positive signals in sham group and ischemia group both in mRNA levels and protein levels. CONCLUSION:The expression of HO-1 in the lung is not induced by limb ischemia or sham operation, but induced by limb reperfusion after ischemia in rats.