Tensile strain induces integrin β1 and ILK expression higher and faster in 3D cultured rat skeletal myoblasts than in 2D cultures

According to previous research, integrin beta 1 and ILK play an important role in the extracellular matrix (ECM)-integrin-cytoskeleton pathway for mechanotransduction. The aim of this study was to investigate strain induced integrin beta 1 and ILK expression in three-dimensional (3D) and in two-dimensional (2D) cultured rat skeletal myoblasts. Sprague-Dawley (SD) rat skeletal myoblasts were isolated and seeded on the PLGA-collagen composite scaffolds. The 3D cultured and the conventionally 2D monolayer cultured myoblasts were loaded 2000 mu strain tensile strain at 0.5 Hz for 2 h, 4 h, 8 h, 12 In and 24 h, respectively with the self-made four-point bending system. The expressions of integrin beta 1 and ILK mRNA were measured by RT-PCR and the different changes between the 3D and 2D cultures were compared. The mRNA expression levels of both integrin beta 1 and ILK were up regulated after mechanical loading (P<0.05), meanwhile, it was higher and peaked faster in 3D cultures than in the 2D cultures. It can be concluded that the ECM-integrin-cytoskeleton pathway responds to tensile strain by elevated expression of integrin beta 1 and ILK, and the response is stronger in 3D cultures than in conventional 2D monolayer cultures. (C) 2009 Elsevier Ltd. All rights reserved.