ABSTRACT
Objective To learn the toxic effects on rats repeatedly exposed to dichloromethane by dermal route at the same dose for 28 days.Methods Seventy two Sprague Dawley rats were divided into six groups:a solvent control group (oliver oil),four exposure groups (0.75,1.5,3.0 and 6.0 g/kg·BW)and a recovery group.Each group included six female and six male rats.The exposure groups were dermal exposed to DCM at 1.5,3.0 and 6.0 g/kg·BW,6 hours/day,5 days/week for four weeks.The recovery group was dermal exposed to 6.0 g/kg BW of DCMduring the same period then recovered for 2 weeks.Clinical signs including body weight and food consumption of each group were observed.After rats were sacrificed,the hematological and serum biochemical parameters were determined.Histopathological examination was performed on selected tissues for all animals.Results The male rats in test groups including four exposure groups and a recovery group,showed decreased body weight gain.Neutrophilia and lymphocytopenia were determined in females of 3.0 and 6.0 g/kg BW groups and males of 1.5,3.0 and 6.0 g/kg BW groups by blood routine test (P <0.05).The mean levels of serum ALT and AST significantly increased in males of 3.0 and 6.0 g/kg BW groups (P <0.05).Only the mean level of serum TG in males of 6.0 g/kg BW group decreased (P <0.05).No significant differences of these indexes were shown in female rats of all exposure groups compared to control group.The exposure -related significant increases on the incidences of epidermis and dermis lesion,hepatocellular degeneration and necrosis were observed in test groups compared to the control group.The rats of recovery group were exhibited normal percentages of lymphocytes and neutrophils,levels of ALT,AST and TG. The skin and hepatocellular lesion were improved to some extent, but not recovered exactly.Conclusion In a 4 -week repeated -dose toxic study,DCM induce dose -related effects in rats involving skin lesion and liver injury with adverse changes in body weight gain of male rats,part parameters of hematology and serum biochemistry .