2024 Volume 38 Issue 2 Pages 55-64
The metabolism of bone tissue is regulated by mechanical stimuli. It has been reported that low-intensity, high-frequency vibratory stimuli can activate bone tissue metabolism. Identifying effective vibration conditions that enhance bone formation could potentially be exploited to prevent the onset and progression of osteoporosis, thereby improving quality of life in an aging society. Experiments using model animals have investigated the effects of various frequencies of vibratory stimuli, but there remains no consensus on the most effective frequency. In this study, we used a simple cell culture system to evaluate the calcium signaling response of osteoblasts subjected to micro-vibratory stimuli at different frequencies. Using a custom-developed vibration device, we applied vibratory stimuli to osteoblasts under microscopic observation and evaluated the calcium signaling response using a fluorescent calcium indicator. The vibratory stimuli were applied from 45 to 120 Hz in 15 Hz increments and from 120 to 45 Hz in 15 Hz decrements. The results of the experiment showed that the highest response rate was obtained at 60 Hz in the 45 to 120 Hz group, and at 105 Hz in the 120 to 45 Hz group. These results suggest that in an experimental system where the frequency is swept, the cells respond at the beginning of stimulation, and that habituation may contribute significantly thereafter.
