Influence of dynamic mechanical strains on matrix protein expression by ligament fibroblasts

The anterior cruciate ligament (ACL) and medial collateral ligament (MCL) are two of the major stabilizing elements in the knee joint. Whereas the MCL readily heals post-traumatically, the ACL fails to exhibit a functional healing response after injury. This differential in the healing capability between these two tissues has been speculated to be a result of intrinsic differences between-the two types of fibroblasts. As with all biological tension-resisting structures, the mechanical properties of the ACL and MCL are crucial to their proper function. One of the factors that govern the tissue strengthening and wound healing processes of tissue are mechanical stimuli. Extracellular mechanical stresses and strains are transduced into the cell, initiate intracellular signal cascades, and ultimately influence the expression of various genes. Since the extracellular matrix (ECM) proteins determine the mechanical properties, this study focuses on the changes in mRNA levels of type I and type III collagen as well as fibronectin that are induced by mechanical stimulation.