Effects of Vitamin E on the Changes of Mineral Contents in Chronic Cadmium-Poisoned Rats

This study was carried out to investigate the effects of vitamin E on the cadmium contents of bone and on the calcium and phosphorous contents of the blood, urine and feces. Male Sprague-Dawley rats weighing 100$\pm$10g were randomly assigned to one normal group and three cadmium poisoned groups. The cadmium poisoned groups consisted of a vitamin E free diet (Cd-0E) group; a 40 mg vitamin E /kg diet (Cd-40E) group; and a 400 mg/kg diet (Cd-400E) group. Experimental animals were maintained on their respective diets for 20 weeks and were simultaneously administered 50 ppm $Cd^{2+}$ dissolved in the drinking water. At the end of the trial, the average hematocrit value in the Cd-0E group was 28.13% lower than in the normal group. However, the average hematocrit value in the Cd-400E group was significantly higher than in the Cd-0E and Cd-40E groups. WBC levels in the cadmium-poisoned groups were lower than in the normal group, but Cd-400E group levels were significantly higher than in the Cd-0E and Cd-40E groups. The contents of calcium of tibia has no significant difference between normal group and cadmium exposed group at $10^{th}$ week After 20 weeks, the calcium contents of the tibia in the Cd-0E and Cd-40E groups were lower than in the normal group by 25.5% and 22.1 %, respectively, although the calcium contents of the tibia in the Cd-400E group were higher than in the normal group. After 10 weeks, the calcium contents of the femur in the Cd-0E and Cd-40E groups were 19.25% and 15.45% lower than in the normal group, respectively, but the calcium contents of the femur in the Cd-400E group were at the same levels as in the normal group. The levels of calcium in the femur after 20 weeks were similar to the 10-week levels. Calcium levels of the urine in the Cd-0E and Cd-40E groups were 3.92 fold and 2.92 fold higher, respectively, than in the normal group, but levels in the Cd-400E group were significantly lower than in either the Cd-0E group or the Cd-40E group. Calcium levels of the feces in cadmium-poisoned groups were significantly higher than in the normal group, although levels in the Cd-400E group were significantly lower than in the Cd-0E and Cd-40E groups. Phosphorous levels of the blood in the Cd-0E group were 17% lower than in the normal group, although levels in the Cd-400E group were significantly higher than in the Cd-0E group. Phosphorous levels of the urine in the Cd-0E and Cd-40E groups were significantly higher than in the normal group, while Cd-400E group levels were found to be at the same level as in the normal group. Cadmium contents of the tibia in the Cd-40E and Cd-400E groups were 13% and 17% lower, respectively, than in the Cd-0E group. Regarding cadmium levels in the femur, only the Cd-400E group achieved lower levels (10% lower) than the Cd-0E group. In conclusion, vitamin E supplementation resulted in a suppression of the release of calcium from bone, and a reduction in the excretion of calcium via the urine and feces, thus having a normalizing effect on calcium metabolism in rats with chronic cadmium poisoning.