The Effect of the Diet Therapy on Endochondral Ossification in the growing stage

2003 Fiscal Year Final Research Report Summary

• Project/Area Number: 14571960
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Kyushu Dental College
• Principal Investigator: NISHIDA Ikuko Kyushu Dental Dollege, School of Dentistry, Assistant Professor, 歯学部, 講師 (80198465)
• Co-Investigator(Kenkyū-buntansha): KIMURA Mitsutaka Kyushu Dental College, School of Dentistry, Professor, 歯学部, 教授 (70047801)
• Project Period (FY): 2002 – 2003
• Keywords: growing stage / Calcium / Ipriflavone / Endochondral Ossification / rat

Research Abstract

It is well-known tact that sufficient calcium intake is necessary for the osteogenesis in the growing stage. However, by national nutrition survey in Japan, the calcium intake is obviously insufficient during most time of life. On the other hand, it is important to increase the bone mineral content as much as possible in the growing stage to prevent osteoporosis. In recent years, ipriflavone (IF) which can inhibit bone resorption and stimulate bone formation is notided. In this study, we reported the effect of calcium and IF on endochondral ossification in growing stage by observing the histopathological and ultrastructural findings.
Insufficient calcium intake raised the debilitated bone in growing stage. The sufficient recovery findings were not obtained, however, even if high calcium diet was given afterwards. In the light microscopy findings, the calcification matrix surrounding chondrocytes in hypertropic zone and the chondroclast that erodes calcification matrix increased, when IF was taken with the high calcium diet. Moreover, in the bone matrix, the metabolize process to bone matrix from cartilage tissue was promoted by increase the number of osteoblast, and the trabeculae were thick and arranged regularly. In the SEM findings, the territorial matrix and distinct border were clear. In the wall of chondral lacunae, multiple distinct calcospherites agglutinated each other.
In the bone matrix, there was widely the bone formation, and there were abundant bone lacunae, which were rounded by regular collagen fibrils. In the TEM findings, the number and the activity of the osteoblast increased. In the cytoplasm, there were well developed Golgi apparatus, mitochondria. The osteoclast were located away from the bone surface. The ruffled border of them were poorly developed. Thus, the bone resorption was inhibited. Mature osteocytes, which had a high nucleus-to-cytoplasm ratio, increased.
In this study, we found that taking IF with calcium the improve the development of chondrocytes and calcifying calcification matrix. And, in the bone matrix, prevent the bone resorption and improve the bone formation. Thus, it was shown that endochodral ossification could be recovered by taking IF with calcium, in growing stage.