Regulation of sepsis-induced apoptosis of pulmonary cells by posttreatment of erdosteine and N-aceylcysteine

This study investigated the frequency of apoptosis in rat pulmonary epithelial cells after intraperitoneal endotoxin (LPS) injection, the effects of LPS on inflammatory markers [myeloperoxidase (MPO), tumor necrosis factor alpha (TNF-α), and vascular endothelial growth factor (VEGF)] in lung damage and the protective effects of two known antioxidant agents, erdosteine and N-acetylcysteine (NAC). Male Wistar rats were divided into six groups, each composed of nine rats: two control groups, two LPS-treated groups, one erdosteine-treated group (150 mg/kg), and one NAC-treated group. LPS was intraperitoneally injected at a dosage of 20 mg/kg. Following LPS injection, the antioxidants were administered orally. The rats were killed 24 h after LPS administration. Lung tissue samples were stained with hematoxylin–eosin (H&E) for histopathological assessments. Apoptosis level in epithelial cells was determined by using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick endlabelling) method. Staining of cytoplasmic TNF-α in epithelial cells and VEGF in endothelial cells, and epithelial MPO activity were evaluated by immunohistochemistry. Posttreatment with erdosteine and NAC significantly reduced the rate of LPS-induced epithelial cell apoptosis. Posttreatment with erdosteine and NAC significantly reduced the increases in the local production of TNF-α and VEGF, and epithelial MPO activity. The effects of NAC on apoptosis, the increases in the local production of TNF-α and VEGF, were weaker than the effects of erdosteine. This finding suggests that the effects of erdosteine at the administered dose on apoptosis regulation are stronger than that of NAC.