Diesel exhaust particulate (DEP) affected thiol levels in both alveolar macrophages (AM) and lymph node cells (LNC).
Al-Humadi NH; Siegel PD; Lewis DM; Ma JY; Ma JK
Toxicologist 2001 Mar; 60(1):167
Glutathione (GSH) and cysteine (CYS) are major intracellular antioxidants and play an important role in protecting against electrophilic xenobiotics. The purpose of this research was to study the thiol regulation by AM and LNC, and the effect of DEP on this process. AM, and thymic and tracheal lymph node lymphocytes were obtained from rats 3 days after intrarracheal instillation of DEP/saline or saline. Cells were cultured + cystine for 16 hour's at 37C and 5% CO2, or used immediately to determine GSH-reductase activity (GSH-R). Determination of cysteine and GSH levels in MBB-strained cells and derivitized culture supernatant was achieved via reverse phase high performance liquid chromatography (HPLC). Both AM and LNC showed enhanced levels of cysteine when incubated with cystine. This enhancement was significantly augmented in cells obtained from DEP exposed rats. The DEP exposure was also shown to enhance GSH production in AM, but not in LNC when cystine was added to the cell culture. Intracellular GSH levels in LNC were decreased in the DEP exposed cells cultured with or without cystine. DEP was found to interact directly with cystine, cysteine, and to a lesser extent with GSH. DEP did not react with oxidized GSH or directly react with GSH-R; however GSH-R activity was greatly induced in LNC from animals exposed to DEP. DEP caused increased uptake and reduction of disulfides in these immune effector cells. The mechanism of this stimulus is not known, but does not appear to be in response to significant intracellular thiol oxidation/depletion by DEP.
Diesel exhausts; Respiratory system disorders; Respiratory irritants; Pulmonary disorders; In vitro studies; Laboratory animals
The Toxicologist. Society of Toxicology 40th Annual Meeting, March 25-29, 2001, San Francisco, California