Chondrons from articular cartilage: I. Immunolocalization of type vi collagen in the pericellular capsule of isolated canine tibial chondrons

TLDR

Type VI collagen localization in the pericellular capsule is linked to chondron integrity and chondrocyte protection during compressive loading. Intact canine tibial chondrons were isolated by low‑speed homogenization and stained with a polyclonal anti‑type VI collagen antibody via indirect immunofluorescence. Anti‑type VI collagen antibody localized to the capsule surrounding chondrocytes, with weaker staining in tail‑like extensions and inter‑chondron connections; frayed collagen bundles and controls showed no staining.

Abstract

ABSTRACT A heterogeneous population of intact chondrons extracted from low-speed homogenates of canine tibial cartilage were stained by indirect immune-fluorescence methods with a polyclonal antibody to type VI collagen. In each of the four chondron groups examined, anti-(type VI collagen) anti-serum was concentrated in the capsule immediately adjacent to the chondrocyte complex. A constant but weaker fluorescent reaction persists in ‘tail-like’ extensions common to single and double chondrons and in the medial connections between adjacent chondrons in linear columns and aggregated clusters. Frayed collagen bundles typical of chondron preparations did not react with the antibody. Similarly, chondrons reacted with normal rabbit serum, or treated by type VI collagen extraction procedures, showed no staining reaction. The differential localization of type VI collagen in the pericellular capsule is discussed in relation to the maintenance of the chondron’s integrity and to the protection of the chondrocyte during dynamic compressive loading.