カルシウムの摂取不足による下顎頭軟骨の成長に関する実験的研究

抄録

Calcium deficient food and low calcium-deficiency food were given for three weeks to Wistar rats of 6-week old corresponding to human school age period and to those 9-week old corresponding to adulthood, and bone debility was induced in them. Then a singular therapy with standard food containing calcium was used, and formation of bone matrix affecting the growth of cartilage of mandibular condyle was investigated. The results were as follows : I. Body weight The rats, 6-week old and 9-week old, were divided into their respective groups and maintained to 12-week old and 15-week old. As a result, no significant differences (p<0.01) were found in any group. The body weight was 6-week old<9-week old. II. Radiological findings 6-week old In the calcium deficient food group as compared with the controls, the trabeculae were found increased in the central and posterior portions but running irregularly. The low calcium-deficiency food group showed the same regularity of trabeculae as the controls. 9-week old In the calcium deficient food group as compared with the controls, the osseous layer was uneven in thickness and the trabeculae were running irregularly. The low calcium-deficiency food group showed about the same findings as the controls. III. Findings on Ca and P analysis on the X-ray Microanalyzer Relative Ca ratio and P ratio were determined by quantitative analysis by point analysis. 6-week old The controls and low calcium-deficiency food group showed about the same relative Ca ratios, but the calcium deficient food group showed low values. Relative P ratios were in the order of the low calcium-deficiency food group>controls>calcium deficient food group. 9-week old Relative Ca ratios were in the order of controls>calcium deficient food group=low calcium-deficiency food group. Relative P ratios were in the order of controls>low calcium-deficiency food group>calcium deficient food group. IV. Histopathological findings 6-week old In the calcium deficient food group as compared with the low calcium-deficiency food group, chondroclasts were restricted in the hypertrophic chondrocyte layer, and intrachondral ossification directly below the invasion zone was decreased. 9-week old In the calcium food group as compared with the controls, intrachondral ossification was restricted. In the low calcium-deficiency food group as in the controls, calcification of the matrix in growing chondrocyte layer was progressed and growth of the mandibular condyle by the mechanism of intrachondral ossification was seen. V. Hematologic findings 6-week old and 9-week old No changes were found in electrolyte in blood serum and in biochemical examinations in any group. Comparison between 6-week old and 9-week old K was high in value (p<0.01) for 6-week old in the low calcium-deficiency food group. Cl was high in value (p<0.01) for 6-week old in the controls and calcium deficent food group. CPK was high in value (p<0.01) for 9-week old in all groups. ALP was high in value (p<0.01) for 6-week old in all groups. On the basis of the foregoing findings, growth of the cartilage of mandibular condyle is affected by insufficient intake of calcium in the growing stage. In the low calcium-deficiency food group especially, findings of recovery of formation of bone matrix related to growth of the cartilage of mandibular condyle were evident.