Abstract: Objective:To explore the protective effect of glutamine(GLN) on the hyperoxia lung injury in the neonatal rats, and to elucidate its mechanism. Methods:A total of 90 male and female Wistar rats were selected and randomly divided into control group (FiO₂=21%), hyperoxia group(FiO₂> 85%) and hyperioxia + glutamine (GLN) group (FiO₂> 85%)(n=30).The rats in hyperioxia group and hyperioxia+GLN groups were used to establish the models of hyperoxia lung injury(HALI).The rats in hyperoxia+ GLN group were intraperitoneally injected with 0.75 g·kg^-1·d^-1 GLN from the first day of experiment, and the rats in other two groups were abdominally injected with the same volume of normal saline. The body weights, water contents in the lung tissue of the neonatal rats in various groups on the 3rd, 7th, and 14th days of the experiment were measured. HE staining was used to determine the morphology of lung tissue of the rats in various groups; ELISA was used to detect the levels of interleukin-6(IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the lung tissue homogenate of the rats in various groups. Results:Compared with control group at the same time, the weights of the neonatal rats in hyperoxia group were significantly decreased on the 3rd, 7th and 14th days(P<0.05); the body weights of neonatal rats in hyperoxia + GLN group were significantly higher than those in hyperoxia group at the same time (P<0.05). On the 3rd, 7th, and 14th days, the water contents of lung tissue of the rats in hyperoxia group were higher than those in control group at the same time(P<0.05), and the difference was gradually increased with the prolongation of time; the water contents of lung tissue of the rats in hyperoxia + GLN group were significantly lower than those in hyperoxia group(P<0.05) on the 3rd,7th, and 14th days. Compared with control group, there was a certain degree of damage of the alveolar structure of the rats in hyperoxia group,accompaying with the alveolar fusion, the interval widening, the fibrous tissue hyperplasia and the interstitial inflammatory exudation;the injury degree was aggravated with the prolongation of time. Compared with hyperoxia group, the degrees of alveolar injury, inflammatory exudation, fibrous tissue hyperplasia of the rats in hyperoxia + GLN group were alleviated. Compared with control group at the same time, the levels of IL-1β, IL-6 and TNF-α in lung tissue homogenate of the rats in hyperoxia group were significantly increased (P<0.05);compared with hyperoxia group, the levels of IL-1β, IL-6, and TNF-α of the rats in hyperoxia + GLN group were significantly decreased(P<0.05). Conclusion:GLN has a protective effect on the neonatal rats with HALI, which can alleviate the hyperoxia-induced pulmonary edema in the neonatal rats and inhibit the expressions of IL-6, IL-1β, and TNF-α in lung tissue.

Key words: hyperoxia lung injury, neonatal rats, glutamine, interleukin-6, interleukin-1β, tumor necrosis factor-α