MAINTENANCE OF EQUINE ARTICULAR-CARTILAGE EXPLANTS IN SERUM-FREE AND SERUM-SUPPLEMENTED MEDIA, COMPARED WITH THAT IN A COMMERCIAL SUPPLEMENTED MEDIUM

Objective-To evaluate the effects of a commercially defined, serum-fre e medium additive on equine articular cartilage explants, compared wit h effects of serum-free and serum-supplemented media. Animals-Articula r cartilage from a 3-year-old, mixed breed horse euthanatized for reas ons other than musculoskeletal disease or sepsis. Procedure-Media were changed every 48 hours, and the glycosaminoglycan (GAG) content was d etermined in media collected at each time point. Glycosaminoglycan syn thesis by explant chondrocytes, and residual GAG content of articular cartilage (as a measure of explant GAG loss) were determined at the en d of the study (day 8). Results-Articular cartilage explants in serum- free medium and the commercial supplemented medium had significantly l ower GAG synthesis and GAG content than did those incubated in serum-s upplemented medium. There were no significant differences in GAG synth esis and content between serum-free and commercial supplemented medium groups. When comparing medium GAG content for all treatment groups, t he GAG content in serum-free medium on day 8 was significantly greater than that in commercial supplemented medium, but significant differen ces were not evident in percentage of release of GAG (as an indicator of GAG degradation) among all 3 treatment groups. Conclusions-Commerci al supplemented medium had effects on articular cartilage matrix GAG l oss into medium equal to those of serum-supplemented medium (eg, both lost articular cartilage explant GAG to a similar degree). However, re sidual articular cartilage GAG content was higher in serum-supplemente d medium, as was GAG synthesis. Commercial supplemented medium appears to either lack the proper ingredients to maintain steady-state GAG sy nthesis, or lacks proper concentrations of these ingredients.