Fibroblast-collagen-matrix contraction: growth-factor signalling and mechanical loading.

Fibroblast-collagen-matrix contraction provides a unique way to study reciprocal geometric and mechanical interactions between fibroblasts and extracellular matrix. Such interactions are difficult to appreciate or examine in routine cell culture because the culture surface is usually fixed in place. Forces exerted on collagen fibrils by cells cause isometric tension to develop in the cells if the collagen resists deformation; by contrast, the cells remain mechanically unloaded in the absence of matrix resistance. Recent evidence suggests that the state of cellular mechanical loading determines the mechanism that cells use to regulate contraction.