Effects of combined mechanical stimulation on the proliferation and differentiation of pre-osteoblasts

Abstract

We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 pre-osteoblasts were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with polycaprolactone (PCL) and poly-L-lactic acid (PLLA) using the salt leaching method. The cells were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10 % strain for cyclic strain and 1.0 MHz and 30 mW/cm 2 for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. Mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly up to 10 days when measured with the cell counting kit-8. However, gene expression analysis of collagen type-I (COL-I), osteocalcin (OC), RUNX2, and osterix (OSX) revealed that the combined mechanical stimulation accelerated the matrix maturation of MC3T3-E1 cells. These results indicate that the combined mechanical stimulation can enhance the differentiation of pre-osteoblasts more efficiently than simple stimuli, in spite of no effect on cell proliferation.

Activation of Fak Expression in Influencing Bone Density by Exercise Training for Decreasis Osteoporotic Risk

“…It then follows the process of differentiation which leads to the formation of bone matrix. The results were not different from the results of research [9] that an increase on the expression of genes responsible for the differentiation of osteoblast gene RUNX2. It leads the process of osteoblast differentiation that leads to bone formation in cultured osteoblast cells by mechanical stress.…”

“…It leads the process of osteoblast differentiation that leads to bone formation in cultured osteoblast cells by mechanical stress. Although mechanical stress can induce osteoblast differentiation and osteogenesis however osteoblast activity enhancement mechanisms are not known yet [9].…”

Combined Effect of Three Types of Biophysical Stimuli for Bone Regeneration

“…[12][13][14][15][16] We hypothesized that combining these biophysical stimuli could be a more powerful method for enhancing osteogenic potential induced by each individual stimulus synergistically. 17 The developed bioreactor was able to generate and transfer both individual and combined biophysical signals using three different stimuli to cells on the 3D scaffolds. This study used previously selected stimulation conditions.…”

Development of an Indirect Stereolithography Technology for Scaffold Fabrication with a Wide Range of Biomaterial Selectivity

“…Phase inversion 20 and salt leaching, 21 which are two methods typically used for traditional scaffold fabrication, were combined with the proposed indirect SL technology to construct dual-pore scaffolds having designed global and local pores. 17 The fabrication procedures are described below.…”