Lung and systemic thiol homeostasis during an acute lung inflammation in the rat

The instillation of Sephadex beads into the lungs of rats induces a sustained, acute inflammatory reaction within the lungs which caused significant increases in whole lung free and total glutathione (GSH) of approximately 30% after 72 h of reaction. Concurrently, levels of free and total cysteine (CySH) were increased by approximately 600% and 300%, respectively. Similarly, extended inflammation raised the intracellular content of free and total GSH in intraluminal cells by approximately 50% whilst causing the accumulation of oxidised CySH in the extracellular lavage fluid. Simultaneously, fluctuative trends were noted in several systemic thiol pools. Liver free and total GSH were shown to fall without alteration to CySH components. In contrast the plasma redox balance of GSH was unaltered but depletions of free and total CySH were noted after 72 h of inflammation. These results are discussed in terms of the occurrence of oxidative stress during acute pulmonary inflammation and the relationship of these observations to systemic thiol homeostasis and observations in other models of oxidant-induced pulmonary toxicity.