UC Irvine

A novel, inexpensive, and uniformly characterized uniaxial stretch device was developed to study the cellular response to mechanical stretch. This device showed a pure uniaxial stretch regime with orders of magnitude difference between the stretched and non-stretched axis. In this thesis bone marrow derived mouse macrophages were cultured on the device for 24 hours under a 1 Hz signal at either 5, 10, 15, or 20% peak strain. These cells were also stimulated with pro-inflammatory cytokines to polarize them to M1 macrophages. These cells responded by aligning and elongating in the direction of strain while their inflammatory signaling produced mixed results. Stretch amplitudes from 5 to 20% did not indicate any significant differences leading to the conclusion that the sensitive range for macrophages may be below 5% peak strain. Adhesion time affected TNF-alpha; secretion but the application of stretch did not have any additional change. Adhesion time also did not affect the stretch induced elongation or orientation of macrophages. Rat neonatal cardiomyocytes were also tested on the device and were found to organize themselves both under tension and compressive strain. Adhesion time did slightly affect the organization of cardiomyocytes. The stretch produced by the device is uniform and effects the shape and organization of these two cell types, coupled with the simplicity of the device, this tool can be used to elucidate stretch induced phenotypic changes.