X-Message-Number: 30184 Date: Thu, 20 Dec 2007 23:37:16 -0800 (PST) From: Subject: Dithiothreitol: powerful protection against toxicity [The mechanism of dithiothreitol protection against allyl alcohol toxicity is apparently unknown. Could dithiothreitol help reduce vitrification solution toxicity as well?] Toxicology. 1994 Jan 26;86(1-2):147-61. Dithiothreitol reversal of allyl alcohol cytotoxicity in isolated rat hepatocytes. Rikans LE, Cai Y. Department of Pharmacology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City 73190. Reversal by dithiothreitol (DTT) of allyl alcohol cytotoxicity was investigated in isolated rat hepatocytes. Allyl alcohol-induced protein sulfhydryl loss, bleb formation, and cell death were prevented by DTT, when it was added to hepatocytes 30 min after the toxicant. The protective effect of DTT also was demonstrated in cells that were washed after 30 min of exposure to allyl alcohol, indicating that protection was not related to inhibition of allyl alcohol metabolism or inactivation of acrolein. DTT reversed the cell surface protrusions that formed during exposure to allyl alcohol, but reversal of blebbing did not insure that the cells would remain viable. Glutathione disulfide was not formed in allyl alcohol-treated cells, and DTT reversal of cytotoxicity occurred without restoring glutathione levels. Moreover, protection against allyl alcohol toxicity required the continuous presence of DTT. The results suggest that initial events in the toxic process are reversible, and that DTT can prevent cytotoxicity if added to hepatocytes before irreversible damage occurs; however, the mechanism by which DTT exerts its protection is not clear. PMID: 8134921 Arch Biochem Biophys. 1989 Dec;275(2):551-8. Allyl alcohol- and acrolein-induced toxicity in isolated rat hepatocytes. Silva JM, O'Brien PJ. Faculty of Pharmacy, University of Toronto, Ontario, Canada. Incubation of isolated hepatocytes with allyl alcohol results in GSH depletion and subsequent cytotoxicity which is prevented by pyrazole, an inhibitor of alcohol dehydrogenase. Both GSH depletion and cytotoxicity were much more rapid when hepatocytes were incubated with acrolein, the reactive metabolite, and were not affected by pyrazole. However, cytotoxicity of both allyl alcohol and acrolein was enhanced by the aldehyde dehydrogenase inhibitors cyanamide and disulfiram. Malondialdehyde, a lipid peroxidation product, was also formed when hepatocytes were incubated with either agent, and treatment of the hepatocytes with a ferric ion chelator, desferrioxamine, or an antioxidant delayed the cytotoxicity without affecting GSH depletion. Although no GSSG was formed and addition of disulfide reductant dithiothreitol did not restore GSH levels, cytotoxicity was prevented if dithiothreitol was added some time after either agent. PMID: 2596853 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=30184