ULTRASTRUCTURE OF RABBIT SEMILUNAR CARTILAGES

Abstract

A light and transmission electron microscopical study of 6-8 mo. old rabbit semilunar cartilages showed more resemblance of cells in this tissue to chrondrocytes than to fibroblasts. The prominent organelles in these cells were rough endoplasmic reticulum and Golgi complex. An unusual finding was the occurrence of filamentous material in Golgi sacs and vesicles, and collagen fibrils within smooth membrane-bound tubular structures, apparently within the cells. Collagen fibrils forming fibers, fiber bundles and lamellae constituted the major component of the menisci. Protein-polysaccharide particles and associated fine filaments were found in the interfibrillary matrix and in the sparse territorial matrix adjacent to the chondrocytes. Numerous immature elastic fibrils and rare mature elastic fibers with an electron-lucent amorphous core were also found in the general matrix among the collagen fibrils.