Induction of cellular glutathione and glutathione S-transferase by 3H-1,2-dithiole-3-thione in rat aortic smooth muscle A10 cells: protection against acrolein-induced toxicity.

There is increasing evidence that aldehydes, including acrolein generated endogenously during the degradation process of biological molecules or the metabolism of foreign chemicals may be involved in the pathogenesis of cardiovascular diseases, such as atherosclerosis. Because glutathione (GSH) and GSH S-transferase (GST) are a major cellular defense against the toxic effects of reactive aldehydes, in this study we have characterized the inducibility of GSH and GST by the unique chemoprotective agent, 3H-1,2-dithiole-3-thione (D3T) and their protective effects against acrolein-induced toxicity in rat aortic smooth muscle A10 cells. Incubation of rat aortic A10 cells with micromolar concentrations of D3T resulted in a concentration- and time-dependent induction of both GSH and GST. Treatment of A10 cells with D3T also led to induction of gamma-glutamylcysteine synthetase, the key enzyme involved in GSH biosynthesis. Notably, the levels of GSH and GST remained higher than basal levels 72 h after removal of D3T from the culture media. To examine the protective effects of D3T-induced GSH and GST against reactive aldehyde-mediated toxicity, A10 cells were pretreated with D3T and then exposed to acrolein. Pretreatment of A10 cells with D3T resulted in a marked decrease of acrolein-induced toxicity as determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction assay and morphological changes. To further demonstrate the involvement of GSH and GST in protecting against acrolein-induced toxicity, buthionine sulfoximine (BSO) and sulfasalazine were used to inhibit cellular GSH biosynthesis and GST activity, respectively. Either depletion of cellular GSH by BSO or inhibition of cellular GST by sulfasalazine led to a marked potentiation of acrolein-induced toxicity in A10 cells. Furthermore, co-treatment of cells with BSO was found to greatly abolish the protective effects of D3T on acrolein-induced toxicity. Taken together, our results demonstrate for the first time that both GSH and GST in aortic smooth muscle cells can be induced by D3T, and that this increased cellular defense affords great protection against reactive aldehyde-induced cardiovascular cell injury.