成年期の虚弱脛骨骨幹皮質骨におけるカルシウム含有食, 1α-OH-D_3 の併用療法に関する実験的研究 : 骨基質形成

抄録

Nine-week-old male Wistar-strain rats were used, corresponding to adulthood in human beings. Calcium deficiency and low calcium diet were fed for 3 weeks, followed by activated Vitamin D_3 for 1 week, and standard diet for another 3 weeks. The effect on formation of bone matrix was investigated, and results were as follows. 1. Body weight No significant differences were revealed among the three groups after 7 weeks of study. 2. Radiographic findings and bone density Calcium deficiency group showed thinner width of interosseous and medial cortice than control group. Bone density showed no significant differences among the three groups. 3. Histopathological findings Bone matrix of diaphyseal cortex was shown densely distributed in control group, inner and outer circumferential lamellae thick, and Haversian system well-formed. Calcium deficiency group showed such findings of bone loss as decreased width of outer circumferential lamellae, decreased Haversian system number, and cavitated osteocytic lacunea. Formation of bone matrix in low calcium group was shown almost the same as in control group. 4. SEM findings Many osteocytic lacunae were seen on superficial layer of interosseous and medial cortice in control group, collagen fibers and deposition of calcifying vesicles were present. Calcium deficiency group showed no significant differences morphologically compared with control group, but the bone contour showed small. Osteocytic lacunae showed indistinct borders with the from surrounding matrix, and irregular-shaped resorptive lacunae were seen. In low calcium group, no changes were found in interosseous and medial cortice compared with control group. The regular-arranged collagen fibers were seen in bone formative layer, the collagen fibric network got dense in superficial area. 5. Hematologic findings Electrolytic, biochemical, and endocrinological examinations showed no significant differences among the three groups. From the aforementioned results, combined treatment with calcium-containing dietary and activated Vitamin D_3 helps with the improvement of bone structure in bone loss resulting from calcium deficiency, as long as bone formation is normal until the adulthood with standard diet feeding. With low calcium diet, bone metabolism was shown to function well, and resulting bone matrix formation almost the same as control group.