OBJECTIVETo study the effect of recombinant human erythropoietin (rhEPO) on apoptosis following hyperoxic lung injury in neonatal rats.

METHODSNinety-six neonatal Sprague-Dawley rats were randomly divided into four groups: air-exposed control, air-exposed rhEPO-treated, hyperoxia-exposed placebo (95% oxygen), and hyperoxia-exposed rhEPO-treated. rhEPO (800 U/kg) was administered 2, 4, and 6 days after air or hyperoxia exposure. The rats were sacrificed 3, 7 and 14 days after air or hyperoxia exposure for the assessment of lung histological changes by hematoxylin and eosin staining (n=8 each time point). p-JNK levels were measured by Western blot. Lung cell apoptosis was evaluated by TUNEL assay.

RESULTSCompared with the air-exposed control group, inflammatory cell infiltration was found at 3 days and increased obviously at 7 days, and widening of the alveolar septa was observed, the number of alveoli decreased and normal alveolarization disappeared at 14 days after hyperoxia exposure in the hyperoxia-exposed placebo group. rhEPO treatment alleviated significantly the hyeroxia-induced alterations in lung pathology. P-JNK protein levels and the number of apoptosis cells decreased significantly in the hyperoxia-exposed rhEPO-treated compared with those in the hyperoxia-exposed placebo group.

CONCLUSIONSrhEPO may reduce apoptosis and thus provide a protective effect against hyperoxic lung injury in neonatal rats. JNK signal pathway may be involved in the protective mechanism.