Effect of Radiation on Bone

Rats subjected to 600 R total body radia-tion were studied. Changes in the epi-physeal cartilage were examined from the morphologic and enzymatic aspects, and were correlated with changes in the mar-row contents and underlying bone. Changes noted were specific for radiation damage and were not caused by nutritional defi-ciencies. Previous studies on the effect of X-irradia-tion on the long bones have included the mode of action, the changes in endochon-dral bone formation, and alterations in the marrow after single or fractional doses.1-5 The results of these studies were variable. Many authors reported a stunting of growth, whereas others believed that irradi-ation did not produce such an effect. De-creases or increases in both osteoblasts and osteoclasts were other changes in dispute. These variations were in part due to the radiation dose used, the animal species studied, the age of the animal, and the du-ration of the postirradiated time studied. The present study was undertaken to deter-mine the early effect of a moderate dose of irradiation on the bones of young animals. Materials and Methods Ninety white male weanling rats of the Holtzman strain, averaging 45.7 gm of body weight each, were alloted to three groups of 30 each. Group A was exposed to 600 R total body radiation. Group B were pair-fed rats (nonirradiated; inanition controls). Food consumption of the irra-diated rats in group A was measured dail