Nephrotoxicities of aluminium and/or cadmium-metallothionein in rats: creatinine excretion and metabolism of selected essential metals.

Abstract

The effects of exposure to aluminium (Al) and cadmium (Cd) on urinary creatinine and protein excretion, and the concentrations of calcium, magnesium and copper in kidney and urine were studied in 32 male adult Wistar rats. The animals were divided into 8 groups, groups 1-4 given a calcium-deficient diet (0.01%, i.e. 0.01 g calcium/100 g diet weight) and groups 5-8 a calcium-adequate diet (0.9%) for 6 weeks. Single daily intraperitoneal injections of AlCl3 (10.8 mg Al/kg body weight, per day) were done on 6 consecutive days to groups 3, 4, 7 and 8 during the last week of the experiment. One single intraperitoneal injection of cadmium-metallothionein (Cd-MT, 0.4 mg Cd/kg) was administered 12 hr before the final Al dose to groups 2, 4, 6, and 8 and the rats were sacrificed 47 hr after the Cd-MT injection. The rate of creatinine clearance was significantly lower in rats injected intraperitoneally with either Cd-MT or Al, and the concentrations of magnesium and calcium in urine were lower in rats administered both Al and Cd-MT as compared to those in control groups. Histological examination showed that Al was toxic to the kidney tubule cells of rats, however, an adequate supply of calcium in food protected to some extent the renal tubules from Al toxicity as indicated by a higher creatinine clearance, and there was also less tubule damage as shown by histological examination. The copper concentrations in kidney tissue were lower in groups treated with either Al or Cd-MT.(ABSTRACT TRUNCATED AT 250 WORDS)