Biochemical effects of intratracheal instillation of cadmium chloride on rat lung

Selected biochemical parameters in rat lung tissue were examined after intratracheal instillation of 0.5 μmole/kg of cadmium chloride (CdCl₂), which produces levels of approximately 10 μg Cd/g of lung wet weight 1 hr following instillation. Lungs were examined 2 hr, 1 day, 3 days and 7 days after CdCl₂ instillation and compared with matched controls receiving saline instillations. Cytosolic lysosomal enzymes, Superoxide dismutase (SOD), catalase, and glutathione (GSH) peroxidase-associated enzymes increased significantly 24 hr after CdCl₂ insult. Peak increases of enzyme activities occurred about 3 days after CdCl₂ instillation. Levels of lung nonprotein sulfhydryl (NPSH) groups, thiobarbituric acid (TBA)-reactive products, protein and DNA increased after CdCl₂ instillation in a similar manner. By 7 days most measured biochemical parameters either remained at the peak 3-day values or decreased toward normal levels. The biochemical changes are consistent with known reported CdCl₂-induced edema and inflammation accompanied by phagocyte recruitment into lung tissue and reparative proliferation of lung cell types.