LUNG AND BLOOD SUPEROXIDE-DISMUTASE ACTIVITY IN MERCURY-VAPOR EXPOSED RATS - EFFECT OF N-ACETYLCYSTEINE TREATMENT

Rats were exposed to mercury vapors (30 mg/m3) for either 1 or 2 h. Histological lesions like alveolar oedema, hyaline membranes and sometimes fibrosis were observed. The lesions were more significant after 2 h of exposure, with about 50% of the animals dying within 2 weeks. The mercury level and the superoxide dismutase activity in the blood and the lungs demonstrated differences according to the time of exposure. In the animals exposed for 2 h to mercury vapors, N-acetycysteine treatment increased survival time and the percentage of living animals. The lung superoxide dismutase was lower than in the non-treated animals indicating an antioxidant effect. Mercury levels were decreased in blood and lung, suggesting some chelating effect of N-acetylcysteine. The exact mechanism of its action must be further elucidated.