ultrasound effect on gene expression of sex determining region y-box 9 (sox9) and transforming growth factor β isoforms in adipose stem cells

Background: cartilage tissue engineering is a promising method for repair of cartilage defects. induction of chondrogenesis in mesenchymal stem cells (msc) is currently used in cartilage tissue engineering. among growth factors, transforming growth factor β (tgf-β ) is common chondrogenic inducer but toward hypertrophic chondrocyte. however, mechanical factors such as ultrasound could stimulate chondrogenesis. objectives:we aimed to investigate stimulation of endogenous tgf-β genes expression by low intensity pulsed ultrasound (lipus) in msc. materials and methods: in this experimental study, adipose tissue stem cells (asc) cultures were treated with or without lipus (30 mw/cm², 20 min/day) and with or without tgf- β 3 (10 ng/ml) for 4 or 14 days. chondrogenic gene expression of sox9 and members of tgf-β family ( 1, 2 and 3) was assessed in asc cultures at day 4 and 14 by real time pcr. results: the gene expression of sox9 significantly increased by lipus and tgf- treatment versus control cultures. exogenous tgf-β 3 treatment stimulated endogenous tgf-β 1 and 2 gene expressions more than lipus treated cultures at day 4. lipus, tgf- and lipus plus tgf-β treated cultures expressed same tgf-β 3 gene expression at day 4. the expression of tgf- β1 and 2 decreased by lipus in comparison to tgf- treated cultures at day 14. conclusions: our results suggest that lipus might initiate differentiation of asc without enhancing endogenous tgf- β genes in in-vitro.