title: 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 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/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, 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.
authors.affiliation: Department of Mechanical Engineering POSTECH Pohang 790-751, Korea.
authors.forename: Kyung Shin
authors.initials: KS
authors.lastname: Kang
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Hak Sue
authors.initials: HS
authors.lastname: Lee
authors.forename: Wonkyu
authors.initials: W
authors.lastname: Moon
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Cho
mesh_terms: D000818:Animals; D019149:Bioreactors; D001861:Bone Regeneration; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D019344:Lactic Acid / Q000737:chemistry; D055595:Mechanical Phenomena; D040542:Mechanotransduction, Cellular / Q000502:physiology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D011091:Polyesters / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry / Q000706:statistics & numerical data
chemical_list: D011091:Polyesters; D011108:Polymers; C016240:polycaprolactone; D019344:Lactic Acid; C033616:poly(lactide)