The mechanism of chloroform toxicity in isolated rat hepatocytes.
Chloroform (CHCl3) is widely used in the manufacture of drugs, cosmetics, plastics and cleaning agents. It is also found in chlorinated drinking water. This study was designed to investigate the toxic effect of CHCl3 on isolated male rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and the cell viability was determined by Trypan blue exclusion. The leakage of cytosolic enzymes such as aspartate transaminase (AST) and alanine transaminase (ALT) after treatment with CHCl3 was measured. Reduced glutathione content (GSH) and its related enzymes, glutathione reductase (GSH-Rx) and glutathione peroxidase (GSH-Px), were also evaluated to study the effect of CHCl3 on hepatocytes. Exposure to 100 and 1000 ppm CHCl3 results in a significant decrease in cell after 30 min incubation. However, the effect of 1 and 10 ppm concentrations was observed at 60 min incubation. AST leakage was significantly increased in all treatment groups, while ALT was significantly increased at 100 and 1000 ppm CHCl3 after 60 and 30 min, respectively. As early as 15 min, GSH was decreased significantly at 1000 ppm, but at 100 and 10 ppm CHCl3 the decrease in GSH began after 30 and 120 min, respectively. GSH-Px activity did not changed. However, the activity of GSH-Rx was significantly decreased at 1000 ppm CHCl3 and at the same time GSH content was decreased. The data indicate that the toxic effect of CHCl3 was dose- and time-dependent. The degree of GSH depletion correlated with increased cytotoxicity and decreased GSH-Rx activity due to CHCl3.
el-Shenawy
N S
NS
Pharmacology and Toxicology Department, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark 07103-2714.
Abdel-Rahman
M S
MS
D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002725:Chloroform / Q000633:toxicity*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D002725:Chloroform; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase