Immunochemical and Mechanical Characterization of Cartilage Subtypes in Rabbit

Abstract

S U M M A R YCartilage is categorized into three general subgroups, hyaline, elastic, and fibrocartilage, based primarily on morphologic criteria and secondarily on collagen (Types I and II) and elastin content. To more precisely define the different cartilage subtypes, rabbit cartilage isolated from joint, nose, auricle, epiglottis, and meniscus was characterized by immunohistochemical (IHC) localization of elastin and of collagen Types I, II, V, VI, and X, by biochemical analysis of total glycosaminoglycan (GAG) content, and by biomechanical indentation assay. Toluidine blue staining and safranin-O staining were used for morphological assessment of the cartilage subtypes. IHC staining of the cartilage samples showed a characteristic pattern of staining for the collagen antibodies that varied in both location and intensity. Auricular cartilage is discriminated from other subtypes by interterritorial elastin staining and no staining for Type VI collagen. Epiglottal cartilage is characterized by positive elastin staining and intense staining for Type VI collagen. The unique pattern for nasal cartilage is intense staining for Type V collagen and collagen X, whereas articular cartilage is negative for elastin (interterritorially) and only weakly positive for collagen Types V and VI. Meniscal cartilage shows the greatest intensity of staining for Type I collagen, weak staining for collagens V and VI, and no staining with antibody to collagen Type X. Matching cartilage samples were categorized by total GAG content, which showed increasing total GAG content from elastic cartilage (auricle, epiglottis) to fibrocartilage (meniscus) to hyaline cartilage (nose, knee joint). Analysis of aggregate modulus showed nasal and auricular cartilage to have the greatest stiffness, epiglottal and meniscal tissue the lowest, and articular cartilage intermediate. This study illustrates the differences and identifies unique characteristics of the different cartilage subtypes in rabbits. The results provide a baseline of data for generating and evaluating engineered repair cartilage tissue synthesized in vitro or for post-implantation analysis.

Differentiation of human embryonic stem cells on three-dimensional polymer scaffolds

“…Addition of TGF-␤ to the medium induced formation of tissue that secreted a cartilage-like glycosaminoglycan extracellular matrix (15), as demonstrated by safranin-O staining (Fig. 2).…”

Parathyroid hormone 1–34 inhibits terminal differentiation of human articular chondrocytes and osteoarthritis progression in rats

“…Samples were digested with enzymes for epitope retrieval before incubation with primary antibodies. The method for enzyme digestion was modified from that described previously (20). The optimal condition for enzyme digestion for type II collagen immunostaining was a mixture of 2.5% hyaluronidase and 1 mg/ml of Pronase in PBS (pH 7.4; Sigma) at 37°C for 1 hour.…”

Mechanical evaluation of bacterial nanocellulose as an implant material for ear cartilage replacement

“…articular cartilage, nasoseptal cartilage) (Mow and Guo, 2002;Rotter et al, 2002) and fibrocartilage (e.g. meniscus) (Joshi et al, 1995) are well documented, yet there is little data available for ear cartilage (Naumann et al, 2002). In comparison to hyaline and fibrocartilage, elastic cartilage contains significantly more elastin (Naumann et al, 2002), which is known to be a highly resilient protein, and which plays a mechanically functional role in tissues like heart valves (Lee et al, 2001) and skin (Oxlund et al, 1988).…”

“…meniscus) (Joshi et al, 1995) are well documented, yet there is little data available for ear cartilage (Naumann et al, 2002). In comparison to hyaline and fibrocartilage, elastic cartilage contains significantly more elastin (Naumann et al, 2002), which is known to be a highly resilient protein, and which plays a mechanically functional role in tissues like heart valves (Lee et al, 2001) and skin (Oxlund et al, 1988). For this reason, a profile of the mechanical properties of ear cartilage is required, since using published mechanical properties of hyaline cartilage or fibrocartilage may not be an appropriate substitute.…”