Exp Mol Med.  2011 Jun;43(6):367-373. 10.3858/emm.2011.43.6.040.

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

• Kang KS
• Lee SJ
• Lee H
• Moon W
• Cho DW

• KMID: 1107378
• DOI: http://doi.org/10.3858/emm.2011.43.6.040

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 and poly-L-lactic acid 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/cm2 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, osteocalcin, RUNX2, and osterix 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.

Keyword

bioreactors; cell differentiation; cyclic strain; physical stimulation; tissue engineering; ultrasound

MeSH Terms

Animals
Bioreactors
*Bone Regeneration
Cell Differentiation
Cell Line
Cell Proliferation
Lactic Acid/chemistry
*Mechanical Processes
Mechanotransduction, Cellular/physiology
Mice
Osteoblasts/cytology/*metabolism
Polyesters/chemistry
Polymers/chemistry
Tissue Engineering/methods
Tissue Scaffolds/chemistry/utilization