A computer-controlled system for mechanostimulation of tissues in culture: a preliminary study of protein synthesis...

During pericardial development or disease, changes in diastolic filling pressure and chamber volumes lead to changes in pericardial stress/strain state. These changes may be transduced into altered cellular synthesis of connective tissue proteins. To study the underlying mechanisms, we have constructed a system in which tissue strips may be subjected to a range of physiologically relevant load-elongation waveforms while being maintained under optimal tissue culture conditions. One sample grip is attached to a 500 g load cell and the other to a linear stepper motor. Load or stroke waveforms and feedback control are achieved under computer control. For preliminary studies, strips of fetal ovine pericardium (127-132 days gestation) and juvenile bovine pericardium (6 months) were subjected to ramp-and-hold loading for 24 hr in culture medium containing tritiated proline. At the end of the experiment, pericardial collagen and elastin were purified biochemically and assessed for tritium content. Preliminary results indicate that loading produced a significant 16% decrease in collagen synthesis (p < 0.02, cpm/mg wet weight) but no change in elastin synthesis. This novel system is a valuable tool for further studies of mechanotransduction in developing, normal, and pathological cardiac tissues.