Response of osteoblasts and osteoclasts in regenerating scales to gravity loading

Abstract

It is known that the teleost scale regenerates after being removed. We previously reported that the osteogenesis in regenerating scales was very similar to that in calvarial bone, which suggests that regenerating scale can be used as a model for osteogenesis to analyze the inte raction b e t we e n oste oblasts and osteoclasts. In the present study, we developed an assay system using regenerating scales by modifying our assay system with normal scales. The weight of one regenerating scale cannot be measured precisely because the rate of calcification in regenerating scales is lower than that in normal scales. In regenerating scales, thus, the respective marker enzyme activit y, i.e ., alkaline phosphatase (ALP) for osteoblasts and tartrate -resistant acid phosphatase (TRAP) for osteoclasts, was normalized by the surface area (mm 2 ) of each goldfish scale. With this modified method, we were able to detect ALP and TRAP activities with no variation in the lines of regenerating scales. In addition, we found that the ALP activity in the regenerating scales significantly increased under 3G acceleration loading by vibration, while the TRAP activity in the loaded regenerating scales significantly decreased. We strongly believe that the regenerating scale is a good material for the analysis of bone me tabolism unde r dif fe re nt gravit y environments.