Effect of mechanical forces on extracellular matrix synthesis by bovine urethral fibroblasts in vitro.

The role of mechanical forces in normal physiological processes is just beginning to be elucidated. Using a system developed in our laboratory, we can apply precise and reproducible mechanical deformations (biaxial strain) to cells. These deformations alter cell activities in a reproducible fashion and may mimic the physical environment found in portions of the urinary tract. At a low strain of 1.8% no change in the synthesis of types I and III collagen by urethral fibroblasts was found. However, at a high strain (4.9%) types I and III collagen showed a significant increase in synthesis compared to controls (type I, 1.4 +/- 0.25 microgram. versus 0.9 +/- 0.27 microgram., p = 0.053; type III, 110 +/- 7 ng. versus 88 +/- 10 ng., p = 0.036). In addition, fibronectin synthesis was increased at low and high strains when compared to controls (low strain 3.20 +/- 1.03 micrograms. versus 1.46 +/- 0.15 microgram., p = 0.042; high strain 8.90 +/- 1.09 micrograms. versus 3.12 +/- 0.69 microgram., p = 0.001). We have shown at the cellular level that mechanical force applied to fetal bovine urethral fibroblasts results in an increase in the amount of collagen synthesis and fibronectin synthesis. These findings suggest that alterations in the physical environment of cells found in the urethral wall can affect biochemical processes including those that govern the synthesis of structural macromolecules such as collagen.