ABSTRACT
OBJECTIVE: This study aimed to analyze cell viability and gene expression interleukin 6 and vascular endothelial growth factor after continuous ultrasound therapy of 1 and 3 MHz in L929 fibroblast cells. DESIGN: The L929 cells were cultivated in 12-well plates and divided into the following five groups: Group 1 (G1), nonirradiated; G2, 0.2 W/cm-1 MHz; G3, 0.5 W/cm-1 MHz; G4, 0.2 W/cm-3 MHz; and G5, 0.5 W/cm-3 MHz. The cells were irradiated at 24 and 48 hrs. Cell viability was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. The gene expression analysis was assessed using real-time polymerase chain reaction. RESULTS: The G2 and G3 showed a decrease in cell viability when compared with the G1 at 48 hrs (P < 0.01). The G4 and G5 presented an increase in viability (P = 0.01 and P = 0.03, respectively) in 24 to 48 hrs. The cells irradiated at an intensity of 0.5 W/cm-3 MHz at 48 hrs showed a 0.21-fold decrease in interleukin-6 gene transcripts and a 1.67-fold increase in vascular endothelial growth factor gene transcripts. CONCLUSIONS: Continuous ultrasound therapy with a frequency of 3 MHz at an intensity of 0.5 W/cm stimulates cell proliferation, decreases interleukin-6 gene expression, and increases vascular endothelial growth factor gene expression in L929 fibroblast cells.
