Properties of Collagen in OIM Mouse Tissues

Abstract

The deletion of the f 2 chain from type I collagen in the oim mouse model of osteogenesis imperfecta has been shown to result in a significant reduction in the mechanical strength of the tail tendon and bone tissue. However, the exact role of the f 2 chain in reducing the mechanical properties is not clear. We now report that the stabilizing intermolecular cross-links in bone are significantly reduced by 27%, thereby contributing to the loss of tensile strength and the change in stress-strain profile. We also report that, in contrast to previous studies, the denaturation temperature of the triple helical molecule and the intact fibers are 2.6° and 1.9°C higher than the corresponding tail tendon collagen from wild-type mice. The increase in hydroxyproline content accounts, at least in part, for the increase in denaturation temperature. The f 2 chain clearly plays an important part in stabilizing the type I collagen triple helix and fiber packing, but further studies are required to determine the precise mechanism.