Biochemical and histopathological effects of subchronic oral exposure of rats to a mixture of five toxic elements

Arsenic, cadmium, lead, chromium and mercury are toxic elements that occur with high frequency in the soil and thus in agricultural products in China. To explore their combined effects, thirty male and thirty female Sprague-Dawley rats were orally exposed to a mixture of these elements at high dose (2.11, 6.47, 72.82, 2.26 and 2.71 mg/kg bw/day), medium dose (1/10 of the high dose) and low dose (1/100 of the high dose) via their drinking water for 90 days. The results revealed that BUN increased in all rats given the high dose, and serum creatinine increased in female rats given the medium dose. Decreased ALP levels in all treated male rats accompanied decreased RBC counts. In the high dose group, serum albumin, globulin and total protein content decreased in male rats, whereas serum ALT levels increased in female rats. Pathological changes were observed in the hepatocytes and renal tubules of all rats given the high dose, and the numbers of spermatogenic cells and sperm significantly decreased in both the epididymides and testes of the rats given the high dose. Abnormalities were observed earlier and more clearly in the males than in the females under combined exposure.