Abstract
We have maeasured the orientation of the collagen fibers in articular cartilage by using H-2 double-quantum-filtered (DQF) spectroscopic imaging that depicts exclusively water interacting with oriented structures. Cartilage and bone plugs 7-8 mm in diameter were obtained from fresh bovine femoral lateral and medial condoyles. The size and orientational dependency of the quadrupolar splitting allows us to estimate the oriented structure of the collagen fibers. In the absence of load, a large quadrupolar splitting is observed in the calcified zone (1320 ± 230 Hz) and a smaller splitting in the radial zone (450 ± 80 Hz). The splitting disappears in the transitional zone and reappears in the superficial zone (160 ± 40 Hz). When the cartilage was rotated by 90 degree and was set its surface parallel to the static magnetic field, the splitting of the calcified and deep layers are halved while the splitting of the surface layer is increased. This is an indication that the fibers align perpendicular to the bone at the deep layer and parallel at the surface. Under static loads, the increase of the splitting at the surface and the thickening of this zone continues which indicate flattening of the collagen fibers near the surface. On the other hand, the splitting at the deep layer completely collapses that may be a result of the crimping of the collagen fibers in this layer. [J Physiol Sci. 2008;58 Suppl:S198]
