RESUMO
AIM: To study the role of high level of endogenous nitric oxide (NO) in apoptosis of alveolar epithelial cells in the development of pulmonary fibrosis in rats. METHODS: The content of nitrite/nitrate (NO 2-/NO 3-) in out-flowing pulmonary blood (OPB) was assayed by nitric acid reduction method. The apoptosis of alveolar epithelial cells was observed by TdT-mediated dUTP nick-end labeling (TUNEL) and electron microscopy, respectively. The above indices were observed on the day 14 and the day 30 after intratracheal administration of BLMA 5 alone or along with blockade of iNOS by aminoguanidine (AG) in rats. RESULTS: (1) Both the content of NO 2-/NO 3- in OPB and the number of apoptotic alveolar epithelial cells in lung were increased in BLMA 5 14 d group, compared with normal control group and BLMA 5 30 d group, respectively (P