The objectives of this study were to investigate whether oral supplementation of
L-2-oxothiazolidine-4-carboxylate (OTC) is effective for increasing tissue
glutathione (GSH) concentrations in rats fed a diet very low (0.5%) in
protein-a model of wasting
malnutrition-and to determine the efficacy of OTC for protection against pulmonary
oxygen toxicity. Weanling rats, fed a 0.5 or 15%
protein diet for 2 wk, were given an oral supplement of OTC, and tissue GSH concentrations were measured over a 24 h period. OTC supplementation to rats fed 0.5%
protein significantly increased GSH concentrations in liver and lung, but not in kidney and blood, when compared with the 0.5%
protein unsupplemented group. The liver GSH concentration in the 0.5%
protein OTC-supplemented group was higher than the 15% control group. Daily supplementation of OTC protected rats from pulmonary
oxygen toxicity during 4 days of 85%
oxygen exposure as determined by lung-to-
body weight ratios and in vivo
proton magnetic resonance imaging. Although
hyperoxia exposure increased lung GSH concentrations in all groups, OTC supplementation was effective for increasing lung GSH concentration in rats fed the 0.5%
protein diet. This study demonstrated that
oral administration of OTC to wasting malnourished rats is an effective procedure to increase GSH concentration rapidly in target organs such as lung, and that daily supplementation of a low dose of OTC has a sustained effect to protect against pulmonary
oxygen toxicity during 4 days of
hyperoxia exposure.