成長期ラットの運動負荷による脛骨骨幹端部への影響 : 電子顕微鏡学的検索

Abstract

The effect of physical exercise on the growth of metaphysis of tibia with electron microscope experimentally and also the effect of calcium intake with normal diet and calcium deficient diet after running exercise were investigated. The results were as follows : I. Scanning electron microscope findings Among normal diet group, bone formation remarkably increased in descending order of 2-exercise, 1-exercise and no exercise groups. In trabeculae, thickness, bone mass and form of arrangement remarkably increased in descending order of 2-exercise, 1-exercise and no exercise groups. The calcium deficient diet and no exercise groups as compared with the control showed thicker chondrocyte layers and increase in width of hypertropic zone in particular. Trabeculae continuing from subchondral bone formation zone showed active resorption findings and were formed thin. Among calcium deficient diet groups, however all groups showed about the same findings. II. Transmission electron microscope findings Among normal diet group, the number of osteoblasts showing active bone formation and osteocytes remarkably increased in 2-exercise, 1-exercise and no exercise groups. In the calcium deficient diet and no exercise groups in comparison with the control, osteoblasts were fewer in number and presented fibroblast-like morphology. The cytoplasm showed marked swelling of mitochondria and a marked increase in cristae. Osteocytes on the whole decreased, but many findings of osteoid osteocytes and young osteocytes were seen. Osteoclasts presented various morphology and were seen to increase and bone resorption was active. Mitochondria showed a tendency toward swelling and rough surfaced endoplasmic reticulum tended to enlarge. But, among calcium deficient diet group, all groups showed about the same findings. On the basis of the foregoing finding, physical exercise promotes the formation of bone matrix in the metaphysis of the tibia. It is therefore essential to take sufficient calcium.