Toxicology and Carcinogenesis Studies of 1,2-Dichlorobenzene (o-Dichlorobenzene) (CAS NO. 95-50-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

摘要

In 13-week studies using F344/N rats and B6C3F1 mice, 500 mg/kg of 1,2-dichlorobenzene(>99% pure) decreased survival in male and female rats when administered in corn oil by gavage five times per week. At this dose, 1,2-dichlorobenzene produced centrolobular necrosis of the liver, hepatocellular degeneration, and depletion of lymphocytes in the thymus and spleen of both sexes of rats and mice. At a dose of 250 mg/kg, necrosis of individual hepatocytes was observed in both sexes of rats and in male mice. Minimal hepatocellular necrosis was observed in a few rats at a dose of 125 mg/kg, but no hepatic alterations were observed in mice at this dose. Renal tubular degeneration was observed in male rats at 500 mg/kg, and multifocal mineralization of the myocardial fibers of the heart and skeletal muscle were seen in mice. The only hematologic changes considered notable were slight decreases in hemoglobin and hematocrit in the 500 mg/kg male and female rats and in red blood cell counts in the 500 mg/kg male rats; no other marked hematological changes were observed in either species.