RESUMEN
We studied fibroblast activity during tendon healing with an in vitro tendon culture model. Tendons were embedded in a translucent collagen gel matrix whose porous nature permitted free nutrient diffusion, fibroblast migration out of the tendon, and microphotographic documentation of fibroblast activity. Experiments were performed using one or more tendons cultured in the same collagen gel. We identified three zones of fibroblast activity in the gel. Zone I was an area of randomly dispersed cells directly adjacent to the tendon where collagen synthesis and remodeling were probably taking place. In zone II, spindle-shaped fibroblasts were aligned pointing away from the cut tendon end forming a sunburst-like aggregate of cells. Zone II fibroblasts were responsible for formation of migration trails by exerting a mechanical force on the collagen matrix, which was evident as a local gel contraction. Zone III was the leading edge of the sunburst populated by the fastest moving fibroblasts, which responded to guidance by other cut tendon ends. We speculate that the collagen gel used in the culture system may help maintain a chemotactic concentration gradient that allows fibroblasts to locate other distal cut tendon surfaces also embedded in the collagen gel.
Asunto(s)
Técnicas de Cultivo , Fibroblastos/fisiología , Tendones/patología , Cicatrización de Heridas/fisiología , Animales , Adhesión Celular , Movimiento Celular , Pollos , Fibroblastos/patología , Adherencias Tisulares/patología , Adhesión del TejidoRESUMEN
Normal neck motion is a complicated phenomenon. A primary motion results from an applied force or torque. Secondary coupled motions also result as a consequence of the primary motion. These resulting coupled motions were measured in isolated cervical motion segments using three-dimensional videophotogrammetry with a coordinate system fixed in space. A cross coupling algorithm provided error correction and conversion from local to true cartesian coordinates. The data were analyzed by computer, and the true coupled motions resulting from any applied force were obtained. A second group of specimens was facetectomized, and the experiments were repeated. After facetectomy, a moment about the anteroposterior axis resulted in marked reduction in lateral displacement, decrease in vertical displacement, and decrease in rotation about the vertical axis. Results were significant at P less than 0.01 and represent a significant decrease in coupled motions resulting from lateral bending. At P less than 0.05, a laterally applied force causes less lateral displacement and lateral flexion, but more longitudinal displacement. Flexion and extension movements are not significantly altered after facetectomy.