In vitro comparison of equine tendon- and bone marrow-derived cells expanded with FGF-2 prior to culturing with tendon matrix and IGF-I

Abstract

This study was performed to determine the effects of fibroblast growth factor-2 (FGF-2) on monolayer expansion of equine tendon- and bone marrow-derived cells prior to culture with autogenous acellular tendon matrix and insulin-like growth factor-I (IGF-I). Progenitor cells were isolated from six young adult horses, expanded in monolayers with FGF-2, and cultured with autogenous acellular pulverized tendon and IGF-I for seven days. Initial cell isolation and subsequent monolayer proliferation were assessed. In the cell: pulverized tendon cultures, cell viability, expression of collagen types I and II, and cartilage oligomeric matrix protein (COMP) mRNAs, collagen and glycosaminoglycans (GAG) syntheses were assessed. Tendon-derived cells proliferated significantly more rapidly in the initial monolayer expansion cultures in comparison to bone marrow-derived cells. Further, monolayer expansion with FGF-2 significantly increased the cell numbers of tendon-derived cells. Expression of collagen type I, collagen type III and COMP mRNAs was higher in tendon-derived cell groups than bone marrow-derived cell groups. However, IGF-I supplementation significantly increased collagen type I and type III mRNA expression in only the bone marrow-derived cell groups. IGF-I supplementation significantly increased collagen synthesis of bone marrow-derived cells. Monolayer expansion with FGF-2 followed by IGF-I supplementation significantly increased proteoglycan synthesis in tendon-derived cells. In summary, tendon-derived cell cultures generated more cells and showed increased matrix synthesis following monolayer expansion with FGF-2 when compared to bone marrow-derived cells. In vivo experiments using FGF-2 expanded tendon-derived cells are warranted to evaluate the effects on tendon healing.