Inhibitory effect of aminoguanidine on bleomycin-induced pulmonary toxicity in rat

AIM: To observe the inhibitory effect of aminoguanidin (AG) on the pulmonar y toxicity induced by bleomycin A(5)(BLM-A(5)) in rat. METHODS: The content s of hydroxyproline, nitrite/nitrate (NO2- / NO3-), and malondialdehyde (MD A), which reflect fibrosis, nitric oxide (NO) production, and hyperoxidativ e injury of lung, were investigated by colorimetry. Histologic and morphome tric examination of lung was also carried out on histological sections stai ned with hematoxylin and eosin (BE). RESULTS: (1) The content of hydroxypro line in lung and MDA in out-going pulmonary blood (OPB) increased from 14 d to 30 d after intratracheal administration of BLM-A5. Collapsed alveoli an d fibrotic areas were seen and a lot of fibroblasts appeared in the lung in terstitum of the rats 30 d after BLM-A5. (2) The NO2- / NO3- content increa sed in supernatant of alveolar macrophage culture and in OPB. ( 3) The incr ement of hydroxyproline in lung and MDA in OPB induced by BLM-A5 was allevi ated by aminoguanidine (AG, 20 mg (.) kg(-1 .) d(-1), ip). AG also reduced the histologic and morphometric changes in lung interstitum. (4) The augmen t of NO2- / NO3- in OPB was blocked by AG. CONCLUSION: AG had inhibitory ef fect on pulmonary injury and fibrosis induced by BLM-A(5), and the inhibito ry effect was related to the decrease of NO production in lung.