Abstract
Male Wistar rats three-week-old corresponding to the human weaning period and fiveweek-old corresponding to the early childhood were given calcium deficient food and low calcium food, and bone debility was induced. Then food was changed to balanced standard food and the effect of food on ossification in the cartilage in the mandibular condyle at the growth stage was investigated. The results were as follows : I. Roentgenological findings As compared with the control groups of 9-week old and 11-week old rats, the low-calcium food group showed decrease in trabeculae and irregular running. As compared with the calcium deficient food group, the state of bone construction in the mandibular condyle cartilage was improved. In comparison of the 9-week old group with the 11-week old group, the 9-week old showed clear dense osseous layers, increase in trabeculae, and regularity. II. Histopathological findings As compared with the 9-week old and 11-week old control groups, in the low calcium food group, calcification of cartilage matrix in the chondrocyte layers and growth of the mandibular condyle were still restrained. As compared with the calcium deficient food group, in the low calcium food group, demarcation of chondrocyte layers became clear ; especially, maturing of chondrocytes (A) and promotion of chondroclasts (B) were seen ; calcification of cartilage matrix was active ; and the trabeculae in the subchondral bone formation zone became thick. In comparison of the 9-week old with the 11-week old, in the 11-week old, growth of the mandibular condyle was expedited. III. Scanning electron microscope findings The low calcium food group, as compared with the 9-week old and 11-week old groups, did not yet show sufficient recovery. As compared with the calcium deficient food group, however, demarcation of chondrocyte lacunae became clear ; fusion of clacospherites was strong ; bone resorption surfaces decreased in the subchondral bone formation zone ; smooth bone formation surfaces were formed actively ; and bone construction was expedited in the low calcium food group. In comparison of the 9-week old with the 11-week old, the 11-week old showed more calcification, more matured bone matrix, and active reconstruction of bone construction. IV. Hematological findings Serum Ca of the 9-week old control group showed high values. The low calcium food group of the 11-week old showed high GOT values. Between the 9-week old group and the 11-week old group, significant differences were found in serum Ca and ALP values between the control and calcium deficient food groups, and in serum P values between the calcium deficient food group and the low calcium food group On the basis of the foregoing findings, storing in the body sufficient calcium in the early childhood and balanced dietotherapy would expedite growth and bone construction of the mandibular condyle once fell into debility.
