SYNOPSIS
The relationship between mechanical stress and cell differentiation is as yet unexplained. We applied mechanical reciprocating motions to mouse ES-D3 cells with a stressing mechanism. The amount of osteocalcin, which is a marker of the bone differentiation and myocardial pulse rate, was measured upon the differentiation of embryoid bodies (EBs) through three-dimensional culture in a collagen gel matrix. The mechanical stress did not have an effect on the differentiation of EBs in to myocardium. However, the amount of osteocalcin in the group to which mechanical stress was applied for 4 hours was about half of that in the control group.
It is expected that stem cells are involved in oral tissue differentiation caused by external forces based on analysis using embryonic stem cells.

Key words: mechanical reciprocating motion, mouse ES cell, myocardial pulse rate, osteocalcin, differentiation