LIPUS inhibits preadipocyte proliferation and increases apoptosis. Primary cultured preadipocytes were treated with different doses of ultrasound (500, 800, 1100, 1400, 1700, and 2000 cycles) and different duration (0.5, 1, and 1.5 min). (A) Preadipocyte proliferation was evaluated with the CCK-8 assay. Ultrasound doses reaching 1700 cycles (average sound intensity 109.44 mW/cm2) led to a remarkable reduction of preadipocyte proliferation. (B) Effects of LIPUS on preadipocytes proliferation were evaluated at different points in time and the 1-min duration was determined to be the optimal duration. (C, D) The early apoptosis rate was analyzed by flow cytometry using Annexin-V-FITC staining. LIPUS treatment increased the number of early apoptotic preadipocytes compared to control treatment. All values are expressed as the mean ± SEM of three independent trials. For (A and B), data were analyzed with one-way ANOVA analysis, for (C), data were analyzed with independent t test. *P<0.05, **P<0.01, ***P<0.001.