[Anti-inflammation and anti-oxidation effects of recombinant human superoxide dismutase on acute lung injury induced by meconium aspiration in infant rats].

ABSTRACT

OBJECTIVE: To investigate the anti-inflammation and anti-oxidation effects of recombinant human CuZn superoxide dismutase(rhSOD) on acute lung injury (ALI) induced by meconium aspiration in rats. METHODS: 1 ml/kg of 20% human newborn meconium suspension was intratracheally (IT) administrated to induce the model of ALI in 32 male Sprage-Dawley rats, and the animals were then randomized to 4 groups 3 treatment groups with IT administration of 5, 10 and 20 mg/kg rhSOD dissolved in 1 ml/kg saline and the control group with IT administration of 1 ml/kg saline. The animals were killed after 24 h of treatments. The measurements included lung tissue wet/dry ratio, broncho-alveolar lavage fluid (BALF) protein, BALF protein/plasma protein (pulmonary permeability index, PPI),lung myeloperoxidase (MPO) and superoxide dismutase (SOD) activity, nitric oxide (NO) and 8-isoprostane levels. Lung injury score was also evaluated. RESULTS: Compared with the control group, pulmonary MPO activity, NO and 8-isoprostane levels were significantly decreased and SOD activity was markedly increased in all rhSOD treatment groups (P<0.05 or 0.01). Compared with the rhSOD 5 mg/kg group, pulmonary 8-isoprostane level was further low in the rhSOD 20 mg/kg group(P=0.01). Lung injury score was decreased in rhSOD 20 mg/kg group (P<0.05). But there were no statistically differences in lung wet/dry, BALF protein and PPI among all groups. CONCLUSION: The results suggest that a single IT dose of 5,10 or 20 mg/kg rhSOD can prevent lung damages in rats with ALI following meconium aspiration.