Fish scale is a calcified tissue which is similar to those found in human bones. Recently, we developed a scale culture system in which osteoblasts and osteoclasts remain intact after being prepared. Using this system, we analyzed the bone metabolism under 2-, 4-, and 7-gravity (G) loading by centrifuge and compared with control (1-G). After loading for 5 and 10 min, the scales were incubated for 6 and 24 h. The osteoblastic and osteoclastic activities were then measured. The osteoblastic activity significantly increased under 2- and 4-G loading. This activity increased remarkably under 7-G loading. On the other hand, we found that the osteoclastic activity significantly decreased under 2-G loading. Under 4-G loading, there was no significant difference between G-loaded scales and control scales. The osteoclastic activity tended to increase under 7-G loading. These results were similar to our previous study of acceleration by vibration. Bone consists of osteoblasts, osteoclasts, and bone matrix. In our culture system including bone matrix, osteoblasts and osteoclasts reacted precisely to G loading by centrifuge. Therefore, we strongly believe that our culture system is useful for the analysis of bone metabolism under G loading.
2008 by Japanese Society for Biological Sciences in Space