Article ID: 2023-001
Diabetic foot ulcers (DFUs) pose a risk of amputation and death, and its effective management requires promotion of early wound healing. Low-frequency vibration (LFV) was found to be effective against DFUs and promoted blood flow in diabetic wounds by improving glycometabolism. Previous studies have revealed that ultrasound (US) therapy also promotes wound healing in DFUs; however, it is unclear whether it improves glycometabolism during wound healing. This study investigated the efficiency of LFV and US therapy in promoting glucose uptake in 3T3-L1 adipocytes. First, we analyzed the cytotoxicity and variation in lipid droplets after US irradiation of 0, 0.5, 1.0, and 3.0 W/cm2 at 3 MHz with a 20% duty cycle. We concluded that US irradiation did not change the cytotoxicity at any intensity; however, US irradiation of 3.0 W/cm2 decreased lipid droplets in 3T3-L1 adipocytes (p＜0.05). As a result of reduction in lipid droplets by high-intensity US irradiation, we selected lower-intensity US (1.0 W/cm2) for further experiments. Next, we investigated 2-deoxyglucose (2-DG) uptake and the relative intracellular Ca2＋ fluorescence ratio between the control, LFV, and US group. The results showed that 2-DG uptake and relative intracellular Ca2＋ fluorescence ratio were enhanced in the LFV group (p＜0.05, 0.01, respectively). In contrast, the US group did not promote 2-DG uptake and Ca2＋ influx in adipocytes. These results indicated that exposure of adipocytes to LFV improved glycometabolism, whereas high-intensity US irradiation reduced the number of lipid droplets.
