Mechanical and biochemical characterization of cartilage explants in serum-free culture

Abstract

Allografts of articular cartilage are both used clinically for tissue-transplantation procedures and experimentally as model systems to study the physiological behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. Chemical mediators in poorly defined culture media can stimulate cells to quickly degrade their surrounding extracellular matrix. This is particularly true of juvenile cartilage which is generally more responsive to chemical stimuli than mature tissue. By carefully modulating the culture media, however, it may be possible to preserve allograft tissue over the long-term while maintaining its original mechanical and biochemical properties. In this study juvenile bovine cartilage explants (both chondral and osteochondral) were cultured in both chemically defined medium and serum-supplemented medium for up to 6 weeks. The mechanical properties and biochemical content of explants cultured in chemically defined medium were enhanced after 2 weeks in culture and thereafter remained stable with no loss of cell viability. In contrast, the mechanical properties of explants in serum-supplemented medium were degraded by ( approximately 70%) along with a concurrent loss of biochemical content (30-40% GAG). These results suggest that long-term maintenance of allografts can be extended significantly by the use of a chemically defined medium.

Requirement for Serum in Medium Supplemented with Insulin-Transferrin-Selenium for Hydrodynamic Cultivation of Engineered Cartilage

“…[21][22][23][24] In agreement with previous reports, 7,20,35,37,39,40 our data revealed that the serum-free and low-serum ITSsupplemented groups resulted in constructs with similar In the first 2 weeks of the cultivation, the serum-free cultures showed more significant decrease in dry weight and increase in water content than the other groups. By day 28, both wet and dry weights of the serum-free constructs were lower than those of the serum-containing constructs, whereas the values of the serum-containing groups were comparable to each other.…”

“…34,35 Low-serum or serum-free media supplemented with ITS have been widely used in the in vitro cultivation of chondrocytes [36][37][38] and development of engineered cartilage. 7,20,35,37,39,40 In these studies, ITS has been shown to be suitable as a partial 7,35,40,41 or full 35,39 serum substitute for chondrocyte growth in the absence of exogenous growth factors or cytokines. Most of these studies, however, were evaluated under static conditions or, in a few cases, under conditions of dynamic compressive loading 7,20,35 ; none of these studies employed or investigated the role of hydrodynamic forces.…”

Influence of Temporary Chondroitinase ABC-Induced Glycosaminoglycan Suppression on Maturation of Tissue-Engineered Cartilage

“…For reference, GAG content is 6-8% w.w. and collagen content is 10-15% w.w. for similar immature cartilage from which the chondrocytes were isolated in this study. 29,30 The 4-week CABC treatment group fared poorly in comparison, producing equilibrium and dynamic moduli of only *100 kPa and 1 MPa, respectively, by day 70, and similarly reduced GAG and collagen content ( Fig. 2A).…”

A Novel Macroporous Polyvinyl Alcohol Scaffold Promotes Chondrocyte Migration and Interface Formation in anIn VitroCartilage Defect Model

“…In deciding on the culture conditions, we decided to use a relatively simple, but established, static culture system with a welldefined culture media. 36 Though this media maintain chondrocyte phenotype and cartilage tissue properties, the lack of growth factors is not representative of a physiologic condition. Studies in the literature have demonstrated that although in vitro cartilage-cartilage interface strength is low, the interface strength can increase 10-fold in vivo in the FIG.…”