ALVEOLAR BONE DYNAMICS IN THE RATS WITH AN EXPERIMENTAL OSTEOPOROSIS

本文报告了低钙饮食引起8周龄和44周龄大鼠下颌骨和股骨骨质疏松的实验结果。本研究旨在探讨低钙饮食对60周龄大鼠以及8周龄和44周龄大鼠是否诱发实验性骨质疏松，以及改变低钙饮食后的骨动力学变化。将大鼠从低钙饮食改为正常钙饮食后，按喂养方式分为三组。低钙组给予低钙饲料16周，低钙组在低钙饲料12周后给予正常饲料4周。制备四环素标记的股骨和下颌骨脱钙切片，进行接触显微放射照相和荧光显微镜观察。测量了骨灰中骨头的重量。此时，由于四环素的干扰，血中钙及股骨、下颌骨中钙的含量均无法测定，低钙组出现实验性骨质疏松，骨量减少。正常低钙组大鼠在正常饮食条件下可恢复低钙饮食引起的骨量减少。

We reported on the results of the experimental osteoporosis which the low-calcium diets brought about the condition of osteoporosis in the mandible as well as in the femur of the 8-week- and 44-week-old rats. However the degree of those influence was stronger in the 8-week-old rats than in the 44-week-old rats.The purpose of this study was to elucidate whether the experimental osteoporosis is induced in the 60-week-old rats as well as 8-week- and 44-week-old rats fed by low calcium diets, and to know the bone dynamics after the diets were changed from the low-calcium contents. dynamics after the diets were changed from the low-calcium contents to the normal calcium contents.The rats were divided to three groups by the feeding methods. In the one ( control group ) the rats were given the normal diets for 16 week, in the another one ( low-Ca group ) the rats were given the low-calcium diets for 16 weeks, and in the third one ( low-normal group ) the rats were given the normal diets for 4 weeks after the low-calcium diets for 12 weeks. The decalcified sections of the femoral bone and the mandibular bone, which were labeled by the tetracycline, we prepared to observe by the contactmicroradiogram and the fluorescent microscopy. The weight of bone laid in ashes was measured. In this time the calcium level in the blood and in the bone both of femur and mandible were unable to be measured because of the disturbance of the tetracycline.In the low-Ca group the experimental osteoporosis was induced and the bone mass was decreased. In the low-normal group the reduction of bone mass induced during the low-calcium diets could be recovered under the normal diets.