Protective Effects Of Naloxne In Neonatal Rats With Hyperoxia Induced Lung Injury

Objective:To investigate the protective effects of naloxone in neonatal rats with hyperoxia induced lung injury.Methods:120 neonatal Wistar rats were divided randomly into three groups (each group n=40)Ⅰ, air control group;Ⅱ, hyperoxic model group;Ⅲ, Naloxone treatment group. The neonatal rats ofⅡandⅢgroups were exposed to 90-95%02. The neonatal rats of I group were exposed to room air for 14 days.Ⅲgroup were treated with intraperitoneal injection of naloxone (1/99 of naloxone/physiological saline 6mg/kg) every day from the secod day. The rats of I and II groups were treated with intraperitoneal injection of physiological saline. On days,10 rats were executed in each group, and lung tissue section of the neonatal rats were stained H-E after 3th,7th, and 14th days. Expression of VEGF, TGF-β1 and IL-8 was examined by immunohistochemical methods.Results:The pathological changes of lung tissue:in control group rats, there was no any obvious pathological changes in different time period. On the third day, small blood vessels dilated and congested, blood vessels and bronchial walls was mild edema, a littler inflammatory cells infiltrated in the model group, the lesion was progressive on the 7th day, alveolus were confluenced mutually and the structure became disordered; on the 14th day, the fibrotic tissue was proliferation and formed bullous emphysema,the lung development was blocked. The pathological changes was slight in the treatment group than that of the model group, the alveolar size was even on the 14th day and a few fiber was formed.In the air control group, the expression of VEGF was increased in the 7th day and high expression in the 14th day. In the model group, the expression of VEGF was decreased in the 7th day and there was no expression in the 14th day. the expressional of VEFG was obviously increase from the 7th day in the treatment group than that of the model group (P<0.01). There was no expression of TGF-β1 in the air control group and the expression of TGF-β1 was gradually increased in the model group; the expression of TGF-β1 was higher in the treatment group than that of the model group (P<0.05, P<0.01). There was no expression of IL-8 in the air control group, and the expression of IL-8 was increasd in the model group, the expression of IL-8 was lower in the treatment group than that of the model group (P<0.05, P<0.01).Conclusion:Naloxone can protect neonatal rats from the hyperoxia lung injury, and have a certain preventive effect against bronchopulmonary dysplasia.