Bone growth changes in pyridoxine-deficient rats.

Male and female rats were fed a commercial diet lacking pyridoxine. Using radiological and histological methods the growth of the long bones in the pyridoxine-deficient rats from 2 wk to 6 mth of age was compared with that in paired-fed and in paired-weight-gain control rats of the same age and sex given the same diet supplemented by daily injections of pyridoxine hydrochloride. Measurements of tibial bone length were significantly reduced in the deficient male rats but not females, possibly due to the reduced requirements for growth in the female. Thin epiphyseal plates were a feature of the limb radiographs in all the pyridoxine-deficient rats. Histologically the growing long-bone ends showed a diminished activity of endochondral ossification with thin epiphyseal cartilage and fewer shorter, broad and irregular bone trabeculae in the metaphyses of the deficient rats. These metaphyseal changes resemble those described in starvation.