Experimental model for stimulation of cultured human osteoblast-like cells by high frequency vibration

Reliable and reproducible experimental methods for studying enhancement of osteoblast proliferation and metabolic activity in vitro provide invaluable tools for the research of biochemical processes involved in bone turnover in vivo. Some of the current methods used for this purpose are based on the ability of the osteoblasts to react metabolically to mechanical stimulation. These methods are based on the hypothesis that intracellular metabolic pathways could be influenced by the excitation of cytoskeletal components by mechanical cell deformation. Based on the same assumptions we developed a new experimental approach of biomechanical stimulation of cultured osteoblast-like cells by vibration. This method is based on the use of a specially designed vibration device that consists of an electric shaker with horizontally mounted well plate containing cell cultures. We used a first passage explant outgrowth of human osteoblast-like cell cultures, originating from samples of cancelous bone, collected from femoral necks of six donors during surgical arthroplasties of osteoarthritic hips. Well plates with replicates of cultured cells were exposed to a sine shaped vibration protocol in a frequency range of 20 - 60 Hz with displacement amplitude of 25 (+/-5) mum. We found that vibration at a distinct set of mechanical parameters of 20 Hz frequency and peak to peak acceleration of 0.5 +/- 0.1 m/sec(2) is optimal for cell proliferation, and at 60 Hz frequency with peak to peak acceleration of 1.3 +/- 0.1 m/sec(2) for metabolic activity. The presented easily reproducible experimental model should improve and simplify further research on the interactions between mechanical stimuli and intracellular biochemical pathways in osteoblasts.