Resumen

OYARZUN, MANUEL; DUSSAUBAT, NELSON  y  GONZALEZ, SERGIO. Effect of 0.25 ppm Ozone exposure on pulmonary damage induced by bleomycin. Biol. Res. [online]. 2005, vol.38, n.4, pp. 353-358. ISSN 0716-9760.  doi: 10.4067/S0716-97602005000400007.

To study the effect of ozone in a chronically damaged lung, we used a bleomycin (BLM) induced pulmonary fibrosis model. Both endotracheal instillation of BLM and O₃ exposure both produce lung inflammation and fibrosis. Oxidative stress would be a common mechanism of damage for both BLM and O₃. Our aim was to assess lung injury induced by 5 and 60 days of intermittent exposure to 0.25 ppm O₃ in rats with bleomycin-induced pulmonary fibrosis. Thirty-day-old Sprague Dawley rats were endotracheally instilled with BLM (1 U/100 g body weight) and, 30 days later, exposed to 0.25 ppm O₃ (0.25 ppm 4 h per day, 5 days a week). Histopatology controls were instilled with saline and breathing room air. Histopathological evaluation of lungs was done 5 and 60 days after O₃ exposure. BLM-induced lung damage did not change after 60 days of intermittent O₃ exposure. Five days of O₃ exposure increased the mean score of BLM-induced pulmonary inflammation and fibrosis (p=0.06). Frequency of bronchopneumonia increased from 1/7 to 6/6 (p <0.001), suggesting that a short-term exposure to O₃ in a previously damaged lung might be a risk factor for developing further lung injury

Palabras clave : bleomycin; histopathology; lung damage; ozone exposure.