Oxygen therapy remains the main component of the ventilation strategy for treatment of patients with
acute lung injury.
Hyperbaric oxygen therapy (HBO(2)) is the intermittent administration of 100%
oxygen at pressure greater than sea level and has been applied widely to alleviate a variety of
hypoxia-related tissue
injuries. The purpose of this study was to evaluate the effect of hyperbaric
oxygen on
acute lung injury induced by intratracheal spraying of
lipopolysaccharide (LPS) in rats. Male Sprague-Dawley rats underwent implantation of a carotid artery
catheter under
general anesthesia. Aerosolized LPS was delivered twice into the lungs via intratracheal
puncture. Animals were either breathing room air (n = 27) or subjected to hyperbaric
oxygen (HBO(2)) exposure (n = 27) 1 h after LPS spraying.
Acute lung injury was evaluated 5 h and 24 h later. Compared with the control group, intratracheal spraying of LPS caused profound
hypoxemia, greater wet/dry weight ratio (W/D) of the lung (5.67 +/- 0.22 vs. 4.98 +/- 0.19), and higher
protein concentration (1706 +/- 168 vs. 200 +/- 90 mg/L) and LDH activity (129 +/- 30 vs. 46 +/- 15, mAbs/min) in bronchoalveolar lavage (BAL) fluid. Intratracheal spraying of LPS also caused significant WBC sequestration in the lung tissue. HBO2 treatment significantly reverted
hypoxemia, reduced
lung injury measures evaluated at 5 and 24 h, and enhanced 24-h animal survival rate (chi = 5.08, P = 0.024). The
malondialdehyde (MDA) concentrations in lung tissue and serum were both increased after LPS spraying. Neither single HBO(2)
therapy nor five sequential daily treatments enhanced MDA production in lung tissue or serum. Our results suggested that hyperbaric
oxygen might reduce
acute lung injury caused by intratracheal spraying of LPS in rats. This treatment modality is not associated with enhancement of oxidative stress to the lung.