Effects of ultrasound stimuli on mechanical and biological properties of ligament fibroblasts
Research hypothesis: Ultrasound stimulation on ligament fibroblasts will increase their elastic modulus, cell proliferation, migration, and synthesis of extracellular matrix (ECM) (Collagen type I, type III and Fibronectin). Data shows the elastic modulus (Pa); cell proliferation (# Cell/mL) on 2nd, 4th, 6th and 10th day of culture; cell migration length (um); synthesis of proteins: collagen type I (ng/mL), type III (ng/mL) and Fibronectin (ng/mL) of treated and control cells. Following ultrasound stimulation (at either 1.0 W/cm2 (Group A) or 2.0 W/cm2 (Group B) for five days every 24 hours, Control cells (Group C) were manipulated identically with ultrasound off) the elastic modulus of ligament fibroblasts decreased (Group A, 22%; Group B, 31%) (p<0.05). Cell proliferation and migration increased by 10% and 4%, (Group A), and decreased by 13% and 11%, (Group B) (p<0.05). Synthesis of type I collagen was increased 100% following high intensity ultrasound stimulation, but no type III collagen synthesis was detected in cells stimulated with low intensity ultrasound or in control cells. Fibronectin production was significantly increased following ultrasound stimulation (79%, Group A; 61%, Group B). Most cells were viable (85%, Group A; 77%, Group B; 86%, Group C).