Abstract：OBJECTIVE: To study the effect of melatonin, a potent antioxidant both in vitro and in vivo, on hyperoxia-induced oxidant/antioxidant imbalance in the lung of neonatal rats with chronic lung disease (CLD). METHODS: Ninety neonatal rats were randomly divided into three groups (n=30 each): air-exposed, hyperoxia-exposed, melatonin-treated (4 mg/kg melatonin was administered 30 minutes before hyperoxia exposure and once daily after exposure). CLD was induced by hyperoxia exposure (FiO2=0.85). Lung specimens were obtained 3, 7, and 14 days after exposure (n=10 each) for histopathologic examination. The levels of total antioxidase capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), myeloperoxidase (MPO), catalase (CAT), nitrite/nitrate, and malondialdehyde (MDA) in the lung were assayed by the spectrophotometer. RESULTS: The histopathologic examination showed that lung damage was obviously alleviated in the melatonin-treated group. The levels of T-AOC, GSH-Px, SOD and CAT in the lung were significantly higher in the melatonin-treated group than those in the other two groups at all time points (P<0.05). The levels of MPO, nitrite/nitrate and MDA in the lung increased significantly in the untreated hypoxia-exposed group compared with those in the air-exposed group at all time points (P<0.05 or 0.01), while the levels of MPO, nitrite/nitrate and MDA in the melatonin-treated group were significantly reduced as compared with the untreated hypoxia-exposed group (P<0.05). CONCLUSIONS: Melatonin may reverse oxidant/antioxidant imbalance in hyperoxia-induced lung disease, thus providing a protective effect against CLD in neonatal rats.［Chin J Contemp Pediatr, 2009, 11 (7):581-584］
PAN Li,XU Wei,FU Jian-Hua et al. Effect of melatonin on hyperoxia-induced oxidant/antioxidant imbalance in the lung of neonatal rats with chronic lung disease[J]. CJCP, 2009, 11(07): 581-584.
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