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Aims: Although low and high intensity sub-sonic vibrations (SSV) have been shown to facilitate wound healing, very few studies have investigated the effects of SSV on 3T3-L1 preadipocytes. Therefore, the present study was undertaken to investigate the influence of SSV on the proliferation and maturation of 3T3-L1 preadipocytes., Main Methods: To evaluate the effect of SSV on 3T3-L1 cell proliferation, the cells were maintained in an apparatus that administered SSV (0.5 V) for 3 days at a frequency of 10, 20, 30, or 40 Hz. In addition, to study the effect of SSV on 3T3-L1 cell maturation, the cells were stimulated with SSV for 6 days at a frequency of 10, 20, 30, or 45 Hz., Key Findings: Sub-sonic vibrations inhibited the proliferation of 3T3-L1 preadipocytes at frequencies of 20 and 30 Hz. Triglyceride levels in cells subjected to SSV at frequencies ranging from 10 to 30 Hz increased compared with those measured in control cells. The expression of adipogenic genes, such as PPAR-γ and C/EBP-α, markedly increased in response to SSV at 20 Hz and 30 Hz during maturation., Significance: These results suggest that SSV affected adipogenic gene expression at 20 and 30 Hz., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Aims: The nuclear receptor peroxisome proliferator-activated receptor (PPAR) gamma plays an important role in adipocyte differentiation. Its ligands, including thiazolidinediones, improve insulin sensitivity in type 2 diabetes. We investigate the effect of magnolol, an ingredient of Magnolia officinalis on adipogenesis and glucose uptake using 3T3-L1 cells., Main Methods: The effect of magnolol on adipocyte differentiation was quantified by measuring Oil Rd O staining using 3T3-L1 cells and C3H10T1/2 cells. And real-time PCR and western blot were used to determine the expression of PPARgamma or PPARgamma target genes, respectively. The effect of magnolol on glucose uptake was performed using 3T3-L1 adipocytes., Key Findings: Magnolol dose-dependently enhanced adipocyte differentiation in 3T3-L1 cells and C3H10T1/2 cells. In the early stage of adipogenesis, magnolol induced gene expression of C/EBPdelta, C/EBPalpha and PPARgamma2 and during adipocyte differentiation, it also induced the expression of PPARgamma target genes such as aP2, LPL and adiponectin. In addition, magnolol it also increase expression of PAPRgamma target gene such as C/EBPalpha and aP2 at mRNA and aP2 protein level in mature adipocytes. In PPARgamma ligand binding assays, magnolol exhibited binding affinity to PPARgamma but its activity was weaker than rosiglitazone. At the same time, magnolol-induced adipogenesis was inhibited by co-treatment of GW9662 both 3T3-L1 cells and C3H10T1/2 cells. In mature 3T3-L1 adipocytes, magnolol increased basal and insulin-stimulated glucose uptake accompanied by the up-regulation of mRNA and protein level of Glut4., Significance: Our results suggest that magnolol could improve insulin sensitivity through the activation of PPARgamma as a ligand.