Evidence for the expression and enzymatic activity of haem oxygenase-1 in the lungs of horses

Abstract

The aim of this study was to characterise the expression of haem oxygenase-1 (HO-1) in healthy lung tissue from horses and to measure its activity. Samples of lung tissue were collected from six horses euthanased for reasons other than respiratory disease. HO-1 expression and activity were detected in type II alveolar epithelial cells, macrophages and neutrophils in all the samples examined. The activity was dependent on the presence of NADPH and inhibited quantitatively by the addition of increasing concentrations of a competitive inhibitor of HO-1, tin mesoporphyrin IX.