Observation on the lung injury induced by normobaric and hyperbaric oxygen exposures in experimental rats

Abstract

Objective Oxygen is often used clinically to treat hypoxia patients,however,prolonged exposure to normobaric oxygen as well as hyperbaric oxygen will induce oxygen toxicity.Our study was designed to explore different manifestations of pulmonary oxygen toxicity (POT) induced by prolonged normobaric and hyperbaric oxygen exposures.Methods Sixty male SD rats were randomly divided into 6 groups and exposed to 0.10、0.15、0.20、0.25 MPa and 0.30 MPa pure oxygen for 56,20,10,8 and 6 hours respectively.Rats exposed to air were used as control.Protein levels and white cell counts in the bronchoalveolar lavage fluid (BALF),wet/dry ratio of the lung and the expression of caspase-3 in lungs were detected after exposure.Results For the 0.10 MPa group,the protein levels and white cell counts in BALF,the wet/dry ratio of lung and the expression of cleaved-caspase-3 all significantly increased,as compared to those of the air group.With the elevation of oxygen partial pressure,these changes tended to decrease.Wet/dry ratio of the lung,protein levels and white cell counts in BALF and the expression of cleaved-caspase-3 all significantly decreased,as compared to those of the 0.10 MPa group.Conclusions Inflammation and apoptosis played an important role in the pathogenesis of normobaric pulmonary oxygen toxicity,however,their role in the pulmonary oxygen toxicity induced by HBO was not so obvious as was observed. Key words: Pulmonary oxygen toxicity ; Hyperbaric oxygen ; Inflammation ; Apoptosis