[Protective effect of interleukin 22 against hyperoxia-induced lung injury in neonatal rats]

Objective To study the protective effect of interleukin-22 (IL-22) against the hyperoxia-induced lung injury in neonatal SD rats. Methods The neonatal SD rats were randomized into control group, hyperoxia group and IL-22 (10 ng/g) treatment group. Each group was randomly divided into three subgroups of 1, 3, 7 days (n=9). Body mass in every group was detected; lung pathological changes were observed by HE staining; tumor necrosis factor α (TNF-α) in lung tissues was tested by quantitative real-time PCR; and IL-1β in plasma was measured by ELISA. Results After exposure to hyperoxia for 1 day, the body mass in the three groups showed no significant difference, and the structure of lung tissues were normal. After exposure to hyperoxia for 3 or 7 days, the body mass in the hyperoxia group was significantly lower, IL-1β in plasma was significantly enhanced, and the structure of lung tissues were destroyed, which aggravated with the time of hyperoxia exposure. TNF-α mRNA level increased obviously in the hyperoxia group. However, when treated with IL-22, TNF-α mRNA was significantly down-regulated in the treatment group. Conclusion IL-22 may play an protective role in hyperoxia-induced lung injury.