虚弱骨に対するカルシトニン, 活性型ビタミン D_3 の併用療法に関する光顕的ならびに電顕的研究 : 下顎頭の変化

Abstract

Three-week-old male rats of Wistar strain were given a calcium-deficient diet and bone debility was induced in them experimentally. The rats were then given additional daily injection of ECT (0.2u/kg, intramusculary injection), a synthetic eel calciton in derivative, and 1α-OH-D_3 (0.1μg/kg, oral administration), an analogue of active type vitamin D_3, three times a week for four weeks. The effect of the combined treatment on the mandibular condyle at growth stage was investigated. The results were as follows : I. Histopathological findings A. CMR findings Granular trabeculae of primary spongiosa in the calcium-deficient diet + ECT + VD_3 group showed an increasing tendency in comparison with the calcium-deficient diet group. Trabeculae of secondary spongiosa in the calcium-deficient diet + ECT + VD_3 group was thicker but calcification was about the same in degrees as compared with that. B. Light microscopic findings The caltilage layers in the calcium-deficient diet + ECT + VD_3 group were thinner due to decrease in hypertrophic chondrocytes in comparison with the calcium-deficient diet group. Increase in calcified matrices surrounding hypertrophic chondrocytes and in findings of erosions of calcified matrices by chondroclasts were seen sporadically. Though trabeculae were thin and many portions of low calcification layers were seen. II. Electron microscopic findings In the scanning electron microscopic obsevation of cartilage layers, cartilage lacunal walls in the calcium-deficient diet + ECT + VD_3 group were occupied by calcospherites and portions with distinct bone lacunae were found in numbers, as compared with the calcium-deficient diet group. In the transmission electron microscopic observation, osteoblasts in the calcium-deficient diet + ECT + VD_3 group showed an increasing tendency and findings of high organelle activities were seen, as compared with the calcium-deficient diet group. Osetocytes showing osteocytic osteolysis that was found in the calcium-deficient diet group decreased in the calcium-deficient diet + ECT + VD_3 group. Osteoclasts in the calcium-deficient diet + ECT + VD_3 group showed conditions of restraint of their organelle activities as compared with the calcium-deficient diet + ECT group and the calcium-deficient diet + VD_3 group. In the calcium-deficient diet + ECT + VD_3 group, scattered findings of many cell clusters appearing to be young osteoclasts were charactertistic in comparison with the calcium-deficient diet group. On the basis of the foregoing findings, the combined treatment method of ECT and 1α-OH-D_3 for bone debility in the mandiblar condyle showed acceleration of growth of cartilage layers and bone construction, but it did not necessarily produce desirable results.