The purpose of the present study was to examine the role of a wholly compounded Nigerian-like diet on the activities of superoxide dismutase (SOD) and Na+/K+ ATPase and level of lipid peroxidation in oral cadmium toxicity. Nine-week-old Wistar albino rats (100 +/- 2.0 g) were exposed to 100 ppm cadmium in drinking water and the Nigerian-like diet (low in protein and high in carbohydrates and fiber) for 16 wk. The results obtained indicate that cadmium reduced weight gain and increased fecal output of rats, which was further potentiated by the Nigerian-like diet. Cadmium was concentrated in the intestine, liver, and kidney, with the highest level observed in the kidney, followed by the liver. The Nigerian-like diet reduced the concentration of cadmium in these tissues. Cadmium increased lipid peroxidation and inhibited SOD and Na+/K+ ATPase in the tissues. These were also aggravated in rats fed the Nigerian-like diet. Because the Nigerian-like diet increased lipid peroxidation and inhibited SOD and Na+/K+ ATPase in the tissues, it rendered rats more susceptible to cadmium toxicity.

The effects of chronic exposure to cadmium (Cd) on some selected biochemical parameters, as well as the possible protective role of aqueous extracts of Hibiscus sabdariffa L petal were studied in 12-wk-old male Wistar albino rats. Exposure to Cd caused a significant increase in plasma Lalanine aminotransferases (ALT) only but with a corresponding decrease in liver L-alanine and L-aspartate aminotransferases (L-ALT, L-AST) when compared to the Cd-free control. Total superoxide dismutase activity was decreased in the liver, testis, and prostate of Cd-exposed rats, whereas malondialdehyde (MDA) concentrations were increased relative to the Cd-free control. The metal significantly increased prostatic acid phosphatase activity in the prostate, but decreased the body weight gain of the rats and organ/body weight ratio for prostate and testis compared to the Cd-free control. Pretreatment of rats with aqueous extract of H. sabdariffa resulted in significantly less hepatotoxicity than with Cd alone as measured by plasma ALT and liver ALT and AST activities. The extract also protected the rats against Cd-induced liver, prostate, and testis lipoperoxidation as evidenced by significantly reduced MDA values in these organs, as well as reduced prostatic acid phosphatase activity in the prostate, when compared to the Cd-only exposed rats. Also, when compared to the organ/body weight ratios obtained from rats exposed to Cd alone the prostate and testis were protected by the extract as shown by enhanced prostate/body weight and testis/body weight ratios of Cd- and extract-treated rats. These data suggest that H. sabdarrifa L might be protective in Cd toxicity.

The purpose of the present study was to evaluate the effect of cadmium on some protein digestive and absorption enzymes in rats. Thirty-six rats were grouped into three groups of 12 animals each; one group received deionised water and acted as control. One group received 445 microM Cd and the last group received 890 microM Cd in their drinking water for a period of one month. The results obtained indicate that increasing the level of cadmium from 445 microM to 890 microM in the drinking water of the rats led to 29% and 23% increase in accumulated cadmium in the proximal and distal small intestine respectively. The body weight gain of rats exposed to 445 microM and 890 microM Cd was decreased by about 24% and 43% respectively when compared with the control. The activities of carboxypeptidase A, dipeptidase and Na+/K+ ATPase were reduced in the mucosa of the proximal end of the small intestine of cadmium exposed rats. The reduction was dose dependent; with the 890 microM Cd exposed rats displaying the least activities. In the distal small intestine, the activities of these enzymes were restored in the 445 microM Cd exposed rats to levels that were not statistically different (P > 0.05) from those observed in the controls. In the 890 microM Cd exposed rats, dipeptidase activity improved by about 80% compared with the activity of the enzyme in the proximal small intestine. Likewise, Na+/K+ ATPase activity increased by about 125% compared with the observed level in the proximal small intestine. The study suggests that cadmium given to rats in drinking water compromise protein digestion and absorption of nutrients particularly in the proximal region of small intestine and could account for weight reduction associated with cadmium toxicity.

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