Cadmium turnover and changes of zinc and copper body status of rats continuously exposed to cadmium and ethanol.

摘要

The effects of continuous exposure to cadmium (Cd) and ethanol on Cd turnover and zinc (Zn) and copper (Cu) body status of male Wistar rats were studied. The animals received an aqueous solution of 10% (w/v) ethanol and/or 50 mg Cd/l as the only drinking fluid for 12 weeks. The concentrations of Zn, Cu and Cd in the serum (or blood), liver, kidneys, spleen, brain, heart, femoral muscle and femur as well as in 24-h urine and faeces specimens were assessed by atomic absorption spectrometry (AAS). Ethanol alone had no effect on Cd accumulation or excretion. By contrast, co-administration of ethanol with Cd influenced the turnover of this toxic metal. Long-term consumption of ethanol alone caused a decrease in femur Zn and liver Cu concentrations. Moreover, the urinary loss of both bioelements decreased, whereas their faecal excretion was increased. Exposure to Cd resulted in an increase in liver and kidney and in a decrease in femur and 24-h urine Zn concentrations. An increase in Cu concentration in the kidney and a decrease in the brain were also noted. Moreover, Cd increased the total pool of Zn in organs (kidneys, liver, spleen, heart and brain), but did not influence that of Cu. Zn concentration in the liver, kidney and spleen of rats co-exposed to Cd and ethanol were increased, but were decreased in the brain and femur, compared to controls. The concentrations of Cu in livers and brains of these rats were decreased, whereas those in kidney, spleen and heart were increased. The urinary excretion of the elements was decreased, whereas their faecal excretion was increased. Moreover, the total amount of Cu in organs decreased below the control value and that of Zn was in the normal range. These changes in Zn and Cu levels could be explained by different effects of both toxic substances, differences in bioelement intakes (due to reduced consumption of drinking solutions and food), and the modifying effect of ethanol on Cd turnover. Our results suggest that alcoholics may be more susceptible to Cd accumulation and its effects on body Zn and Cu.