RESPONSE OF LIGAMENTOUS FIBROBLASTS TO ME CHANICAL STIMULATION

Mechanical stimulation, as provided by physiotherapy or controlled mot ion is essentially the only factor able to improve anterior cruciate l igament (ACL) healing. We investigate the cellular effects of such sti mulus. Two types of stimulations are applied on canine ACL fibroblasts : repetitive stretch of an elastomeric adhesion substrate and a lamina r flow of culture media over the culture surface. Cell orientation, pr oliferation rate, synthesis and type of collagen as well as proteoglyc ans (PG) synthesis and hydrodynamic characteristics have been studied. According to our results, the fibroblasts tend to align perpendicular ly to the deformation axis of their substrate, and along a laminar flo w, The shear stress induced by the laminar flow does not modify signif icantly proliferation rate nor extracellular matrix synthesis. Substra te stretching however, increases proliferation rate, collagen synthesi s, mostly type III, and PG synthesis, principally of small sizes, The characteristics of fibroblasts submitted to repeated deformation match those of fibroblasts from ligament scar tissues. Their orientation pe rpendicular to substratum deformation differs from the one usually enc ountered in the undamaged tissue: aligned on the ligament axis.