Regulation of nicotine-induced apoptosis of pulmonary artery endothelial cells by treatment of N-acetylcysteine and vitamin E

Abstract

This study investigated the frequency of apoptosis in rat pulmonary artery endothelial cells after intraperitoneal nicotine injection, examining the roles of the inflammatory markers myeloperoxidase (MPO), tumour necrosis factor alpha (TNF-α ), and vascular endothelial growth factor (VEGF) in nicotine-induced vascular damage and the protective effects of two known antioxidant agents, N-acetylcysteine (NAC) and vitamin E. Female Wistar rats were divided into four groups, each composed of nine rats: negative control group, positive control group, NACtreated group (500 mg/kg), and vitamin E-treated group (500 mg/kg). Nicotine was intraperitoneally injected at a dosage of 0.6 mg/kg for 21 days. Following nicotine injection, the antioxidants were administered orally; treatment was continued until the rats were killed. Lung tissue samples were stained with hematoxylin-eosin (H&E) for histopathological assessments. Apoptosis level in endothelial cells was determined by using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick endlabelling) method. Staining of cytoplasmic TNF-α and VEGF in endothelial cells, and perivascular MPO activity were evaluated by immunohistochemistry. The treatments with NAC and vitamin E significantly reduced the rate of nicotine-induced endothelial cell apoptosis. NAC and vitamin E significantly reduced the increases in the local production of TNF-α and VEGF, and perivascular MPO activity. This findings suggest that NAC can be as effective as vitamin E in protecting against nicotine-induced endothelial cell apoptosis. Human & Experimental Toxicology (2007) 26: 595—602.