Repressive effects of a capacitive-resistive electric transfer (CRet) hyperthermic apparatus combined with provitamin C on intracellular lipid-droplets formation in adipocytes

摘要

Purpose: The aim of this study was to evaluate inhibitory effects of L-ascorbic acid-2-O-phosphate-Nasub2/sub (APS), a pro-vitamin C, combined with hyperthermia on adipogenic differentiation of mouse stromal cells, OP9. Materials and methods: OP9 preadipocytes were differentiated with serum replacement, administered with APS, and simultaneously treated with hyperthermia using a capacitive-resistive electric transfer (CRet) apparatus, which was conducted repeatedly twice a day. After 2 days, intracellular lipid droplets were stained with Oil Red O, then observed by microscopy and assessed spectrophotometrically. Results: After stimulation by serum replacement for 2 days, lipid droplets were accumulated surrounding nucleus of OP9 cells. When APS of 0.15–0.6?mM was administered without hyperthermia, the amount of lipid droplets was markedly suppressed to 50.5%～?11.3% versus the undifferentiated control, and diminished huge aggregates of lipid droplets. In OP9 cells treated by hyperthermia at 42°C for 0.5?min, 1?min or 3?min in the absence of APS, adipogenesis was suppressed abruptly in a time-dependent manner to 95.4%, 18.7% or ?5.5%, respectively. Whereas, the percentage of adipogenesis was 96.8% in OP9 cells treated by mild hyperthermia alone at 41°C for 1?min. The simultaneous application of APS and hyperthermia at 41°C for 1?min markedly suppressed the accumulation of lipid droplets to 25.7%～?66.2%. By scanning electron microscopy (SEM) observation, the surface of OP9 cells treated with APS and hyperthermia appeared to have the morphological property of undifferentiated OP9 cells. Conclusion: Combined treatment of APS and mild hyperthermia suppresses adipogenesis in OP9 cells, particularly in lipid droplets accumulation during spontaneous differentiation of OP9 preadipocytes.