H 2O 2 induces apoptosis in bovine tracheal epithelial cells in vitro

Abstract

Oxidants play an important role in the pathogenesis of various airway diseases. Oxidants have been shown to induce two distinct types of cell Death, i.e., apoptosis and necrosis. However, whether oxidants induce apoptosis in airway epithelial cells remains unclear. To address this question, we evaluated the effect of H 2O 2 exposure on bovine tracheal epithelial cells cultured under different conditions. When tracheal epithelial cells were isolated and exposed to H 2O 2 in suspension cultures, they underwent apoptosis as demonstrated by characteristic ultrastructural changes and DNA fragmentation. Interestingly, apoptosis occurred in single cells but not in aggregated cells. In addition, apoptosis was seen in many ciliated and in fewer mucous cells. When tracheal epithelial cells were allowed to attach to the substrate and grow, they became resistant to apoptosis induced by H 2O 2. These results suggest that H 2O 2 can induce apoptosis in airway epithelial cells.