Tensile strain induces integrin beta1 and ILK expression higher and faster in 3D cultured rat skeletal myoblasts than in 2D cultures.

According to previous research, integrin beta1 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 beta1 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 microstrain tensile strain at 0.5Hz for 2h, 4h, 8h, 12h and 24h, respectively with the self-made four-point bending system. The expressions of integrin beta1 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 beta1 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 beta1 and ILK, and the response is stronger in 3D cultures than in conventional 2D monolayer cultures.