虚弱骨に対する生理活性物質の影響に関する X 線的, 光顕的ならびに電顕的研究 : とくに下顎頭の変化
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概要
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Three-week-old rats of Wistar strain were given a calciumdeficient diet for three weeks and experimental condition of bone dibility was induced in them. The rats were then given a normal diet containing calcium and 1 α-OH-D_3, a physiologically active substance, was administered at the same time for two weeks, and the effects of the administration on the mandibular condyle at growth stage were examined. The results were as follows : 1. General tissue findings In comparison with the controls on a normal diet, the calcium-deficient diet group showed irregular borders between erosive zone and hypertrophic zone. Bone trabeculae of subchondral bone formation zone decreased in number. The calcium-deficient diet + a normal diet group showed active subchondral bone formation and many findings of hypocalcification of bone layers. Although bone trabeculae were thin, they increased in number and increase in osteoblasts on the surface of trabeculae was marked. The calcium-deficient + a normal diet + Vitamin D_3 group showed decrease in number of hypertrophic chondrocytes, but increase in volume ofcalcified matrix surrounding hypertrophic chondrocytes and in findings of erosions of calcified matrix by chondroclasts. Subchondral bone formation was active and bone trabeculae were more in number, but they were still thin. 2. Transmission electron microscopic findings In the calcium-deficient diet group in comparison with the controls on a normal diet, osteoblasts were fewer in number and presented fibroblasts-like morphology. The cytoplasm showed marked swelling of mitochondria and a marked increase in cristae. Osteocytes were found in spacious bone lacunae, had well-developed rough surfaced endoplasmic reticulum, and showed unclear lamina limitans in part. Osteoclasts were more in number and many ruffled borders were well developed and active in bone resorption. In the calcium-deficient + a normal diet group in comparison with the calcium-deficient diet group, osteoblasts increased in number and the organelle were active. Young osteocytes increased and osteoclasts also increased in number. In the calcium-deficient diet + a standard diet + Vitamin D_3 group, osteoblasts were about circular in form and increased in number. They showed marked development of rough surfaced endoplasmic reticulum and mitochondria. Osteoblasts in close proximity of osteoclasts increased in number and many findings of increased distances between osteoblasts were seen. Significantly, osteocystes ranged from the young to the matured.
- 九州歯科学会の論文
- 1990-12-25