[Pathological study of experimental osteoporosis]

Effects of uni- or bi-lateral resection of the sciatic nerve followed by calcium deficiency on the bone structure of the adult male rat were studied and the mechanism of the development of osteoporosis was discussed. After the evaluation of the thickness of the cortex and trabecula of the lower leg bone by X-ray morphometry, the bone was excised, calcium and phosphate contents of the bone were analyzed and histopathological and ultrastructural examinations were made on the calcaneus and the lower leg bone. Reduction of the bone trabecular area and of the thickness of the cortex, a loss of dry weight and of calcium and phosphate contents and decrease in the number of osteoblasts and osteocytes were induced to the bone with sciatic denervation. The ultrastructural changes of the osteogenic cells were also observed. The osteoblasts turned to be smoothly surfaced showing only a few cytoplasmic projections were connected loosely each other. These changes were enhanced by calcium deficiency. We concluded from these results that the disturbance of nerve connection and the calcium deficiency contributed to the development of experimental osteoporosis of rats.