Jennifer J. Warnock, Aaron Stoker, Derek B. Fox, James L. Cook.
University of Missouri, Columbia, Missouri, United States

ACVS Abstract 2007 

Osteoarthritic synovium may be biologically primed to undergo chondrogenic differentiation, which could be useful for meniscal fibrocartilage tissue engineering. We hypothesized that osteoarthritic fibroblast-like synoviocytes (FLS) cultured in monolayer and treated with chondrogenic growth factors would have higher fibrocartilage extracellular matrix gene expression, matrix production, and expression of fetal chondrogenic genes.

Normal and osteoarthritic FLS were cultured in monolayer alone (groups NC and OC respectively) and in the presence of chondrogenic growth factors (Basic Fibroblast Growth Factor, for 3 days, followed with Transforming Growth Factor b-1 and Insulin-like Growth Factor- 1 for 13 days (groups NGF and OGF respectively). Extracellular matrix production and cellularity were measured using glycosaminoglycan, hydroxyproline, and double stranded DNA spectrophotometric assays.

Real-time reverse transcriptase PCR was used to identify relative expression of collagen I, aggrecan, SOX-9, Frzb, and Rgs-10 genes as a ratio to GADPH. Hydroxyproline was higher in growth factortreated groups than non-treated groups and higher in NGF versus OGF (P=0.037). Collagen I was expressed in all groups, but was higher in NC (P=0.028) and NGF (P<0.001) groups. Glycosaminoglygan content was greatest in NGF and OGF groups (P<0.001) with no difference between the two. Aggrecan expression was higher in treated groups than controls, but not significantly different between NGF and OGF groups. OGF groups had the highest expression of SOX-9, Rgs-10, and Frzb (P<0.001).

In vitro fibrochondrogenesis was enhanced by growth factor stimulation, and was similar in osteoarthritic FLS and normal FLS. Growth factor induced transcription of embryonic chondrogenic genes may be involved in the process of in vitro chondrogenesis, and these genes may be targets for future fibrocartilage engineering.