Effects of hydrogen sulfide on hyperoxia-induced lung injury in neonatal rats

Abstract

Objective To explore the effects of hydrogen sulfide (H2S) on hyperoxia-induced lung injury in neonatal rats.Methods Eighty full-term Sprague-Dawley rats within 12 hours after birth were randomly divided into control group,hyperoxia group,sodium hydrosulfide (NaHS) + hyperoxia group (NaHS 90 μmol/kg injected intraperitoneally) and propargylglycine (PPG) +hyperoxia group (PPG 50 mg/kg injected intraperitoneally).Except for the control group,the other three groups were exposed to 95％ O2 for seven days.Pulmonary histopathology was observed after HE staining,numeration of leukocyte and albumin in bronchoalveolar lavage fluid (BALF) were processed by optical microscope and Lowry methods.The plasma H2S concentration,activity of cystathionine-γ-lyase (CSE) and contents of malondialdehyde (MDA) in lung tissues were also detected.Analysis of variance and LSD-t test were used for statistics.Results (1) Compared with the control group,alveolar hemorrhage,interstitial edema,inflammatory cell infiltration were observed in the hyperoxia group.The number of white blood cells,neutrophils and albumin content in BALF increased in the hyperoxia group [(130.2± 15.3) × 107/L vs (15.1 ±2.5) × 107/L; (64.6± 12.4) × 107/L vs (2.1 ±0.5) × 107/L; (934.6± 106.4) mg/L vs (254.3±50.7) mg/L,respectively.LSD-t=-14.65,5.78 and 2.97,all P＜0.01],but the plasma H2S concentration and the activity of CSE in lung tissue decreased [(112.6± 20.4) μmol/Lvs (182.3±15.7) μ mol/L,LSD-t=-9.90; (3.4±0.4) μmol/ (min·g) vs (6.8± 1.4) μ mol/ (min · g),LSD-t=-4.59; both P＜0.01].However,the contents of MDA increased [(1.7± 0.3) nmol/ml vs (0.9±0.1) nmol/ml,LSD-t=3.03,P＜0.01].(2) Compared with the hyperoxia group,inflammatory exudation and structural disorder of lung tissue were alleviated in the NaHS+hyperoxia group.White blood cells [(56.3± 11.6) × 107/L],neutrophils [(34.8±7.8) × 107/L] and albumin content [(753.8± 89.6) mg/L] in BALF decreased significantly (LSD-t=-9.66,-11.81 and-5.78,P＜0.01).The plasma H2S concentration [(235.7±32.7) μ mol/L] and the activity ofCSE [(5.8± 1.1) μ mol/(min · g)] increased significantly (LSD-t=11.34 and 5.98,P＜0.01) in the NaHS+hyperoxia group.(3) Compared with the hyperoxia group,inflammatory exudation and structural disorder of lung tissue were more severe in PPG+ hyperoxia group.White blood cells,neutrophils and albumin content in BALF increased significantly (LSD-t=5.52,6.37 and 8.23,P＜0.01),the plasma H2S concentration and the activity of CSE decreased (LSD-t=-4.29 and-3.97,P＜0.01),the contents of MDA increased (LSD-t=3.02,P＜0.01).Conclusions H2S is involved in the pathophysiological process of hyperoxia-induced lung injury in neonatal rats.Exogenous H2S can alleviate the pulmonary injury by inhibiting inflammatory reaction and oxidative stress. Key words: Hydrogen sulfide; Hyperoxia; Lung diseasea; Animals, newborn