Submicroscopic Structure of Equine Articular Cartilage

Abstract

The articular cartilage of knee and tarsal joints was studied by transmission electron microscopy in two 2-and two 8-year-old male horses. Samples were collected from regions subjected to mechanical loading.The superficial layer in both age categories was characterized by spindle-shaped chondrocytes distributed throughout the whole layer and lying parallel to the surface. The 8-year-old horses showed signs of arthrosis, such as uncovering of cells which, consequently, came into contact with the joint cavity, disappearance of the chondrosynovial membrane, presence of fissures in the intercellular matrix and, occasionally, cell necrosis. These changes were associated with a thickening of collagen fibrils.The middle layer was characterized by oval chondrocytes, surrounded by a narrow pericellular matrix, located in the extracellular matrix and by rounded cells sending out short projections into the intercellular matrix. The cytoplasm of both cell types contained cell organelles, glycogen and bundles of intermediate filaments as well as crystals, probably of protein origin, which assumed rhombic, rhomboid or trapezoidal shapes.The deep layer consisted of isogenetic groups of chondrocytes aligned in columns perpendicular to the cartilage surface. The cells were localized in lacunae with a narrow pericellular space. Their numerous projections extended into the intercellular matrix. The cytoplasm showed distinct bundles of intermediate filaments encircling the nucleus. In the vicinity of the tide mark, fibrocytes were observed. The extracellular matrix in this layer was composed of thick bundles of collagen fibrils.

Equine Articular Chondrocytes on MACT Scaffolds for Cartilage Defect Treatment

“…Our study revealed many similarities between equine and human chondrocyte constructs (Nürnberger and Marlovits, ; Nuernberger et al., ), indicating a similar growth behaviour of the cells. This correlation points to the similarity of the equine and human parameters, that is, the transplant material, the seeding strategy and the chondrocytes (Horký and Tichý, ; Nürnberger et al., ). The only difference between the behaviours of equine and human cells was that the equine chondrocyte seemed to be metabolically more active and produced more ECM.…”

Giant crystals inside mitochondria of equine chondrocytes

“…The current study is to our knowledge the first one characterizing extensive protein crystals in mitochondria of chondrocytes. In one publication describing the ultrastructure of equine cartilage, crystals were mentioned and shown in ultrastructural images of equine chondrocyte (Horký and Tichý 2002 ) but without any description of their subcellular localization and structure. Shape and size of those crystals were the same as in this study, and samples were also taken from articular cartilage of horse.…”

Cartilage Regeneration Using a Fibrin and Autologous Cultured Chondrocytes Mixture in a Canine Model

“…A transmission electron microscope was used to observe the ultrastructure of the regenerated cartilage generated in each experimental animal which had been injected with fibrin and chondrocyte.The regenerated cartilage was washed with DPBS(Dulbecco's Phosphate-Buffered Saline, Gibco, Gaithersburg, MD, USA), was then fixed using a universal fixative (formaldehyde/glutaradehyde) and post-fixed using osmium tetroxide (Sigma, Poole, UK), and was finally embedded in resin.The serial sections were mounted on oval, 2-mm, one-hole grids and were stained with uranyl acetate and lead citrate in order to be able to perform electron microscopy (Leica,Wetzlar, Germany) [19][20][21].…”