EFFECT OF CADMIUM ON BONE REPAIR IN YOUNG-RATS

The effect of cadmium (Cd) in drinking water on repair of bone at a si te of hole injury to the tibia of young rats was followed using quanti tative methods. The rats (3-4 wk old) were given 20 ppm and 200 ppm Cd for 5 wk and compared to a control group. A slight reduction (about 1 0%) in body weight and water and food consumption was observed in cadm ium-exposed rats as compared to control rats. Clinical chemistry tests in the blood and histology of kidney, liver, and bone did not indicat e changes related to Cd toxicity. A significant reduction (43%) in alk aline phosphatase (AIP) and tartarate-resistant acid phosphatase (TRAP ) (46%) enzymatic activity was observed at 4 and 7 d postiniury respec tively, in the site of injury in the rats receiving 200 ppm Cd in drin king water as compared to control rats. Calcium accumulation in the ne wly formed repair tissue at the site of injury was also significantly reduced (53%) at 13 d postinjury in the Cd-treated (200 ppm) rats as c ompared to control rats. It is concluded that Cd probably exhibits an effect on the bone repair process as reflected by reduction in ALP act ivity (osteoblastic cells) and mineralization at the site of injury in the tibia of young rats.