Histomorphometric study on the osteocyte lacuno-canalicular network in animals of different species. II. Parallel-fibered and lamellar bones.

The shape, size and density of osteocyte lacunae in parallel-fibered and lamellar bone were histomorphometrically analyzed in relation to the organization of the collagen fiber texture and the animal species (frog, sheep, dog, bovine, horse and man). The following parameters were measured under the light microscope (LM) by a computer-assisted image analyzer: 1) shape, size and distribution of osteocyte lacunae; 2) osteocyte lacuno-canalicular density. In close agreement with our previous studies, which includes woven bone, it resulted that in all animals (even in frog) osteocyte lacunae have a rounded globous shape in woven bone and an oval shape in both parallel-fibered and lamellar bone; in the latter, however, they are more flattened, only located in loose lamellae and thus regularly distributed in rows. Osteocyte lacunar density is higher in woven-fibered, intermediate in parallel-fibered and lower in lamellar bone, whereas no correlation seems to exist with the animal species. In conclusion, these results suggest that osteocyte shape, size and density seem to depend mainly on collagen fiber texture rather than on the animal species. The role of osteocyte-recruitment on the spatial organization of collagen fibers in bone tissues is discussed.