Abstract
In the present study, we explore the effects of a lower infrasonic intensity on biological features of osteoblast-like MC3T3-E1 cells in vitro. Cells were seeded into plate at a density of 1 × 104/ml and were exposed to 100 decibel (dB) infrasonic pressures at several different frequencies, 4, 12, and 20 Hz, respectively for 30 min daily. After five days, cell proliferation was determined by cell counting. Alkaline phosphatase activity (ALP) was detected by a biochemical analysis and the synthesis of osteocalcin (OCN) was measured by a radio-immunological assay. Cell numbers increased significantly from the third day when infrasonic stimuli were used at frequencies of 4 or 12 Hz (P<0.05), and from the fifth day at the frequency of 20 Hz (P<0.05). Although ALP activities were low both in infrasonic exposed groups and the control group (p>0.05), OCN activity was much higher in each infrasonic exposed group compared to the control group (P<0.01). It was concluded that 100 dB infrasonic exposures might promote osteoblast-like cells growth and secretion activity in vitro.