Comparison of equine tendonq- and bone marrow-derived cells cultured on tendon matrix with or without insulin-like growth factor-I supplementation

Objective To compare in vitro expansion, explant colonization, and matrix synthesis of equine tendon- and bone marrow-derived cells in response to insulin-like growth factor-I (IGF-1) supplementation. Sample-Cells isolated from 7 young adult horses. Procedures-Tendon- and bone marrow-derived progenitor cells were isolated, evaluated for yield, and cultured on autogenous cell-free tendon matrix for 7 days. Samples were analyzed for cell viability and expression of collagen type I, collagen type III, and cartilage oligomeric matrix protein mRNAs. Collagen and glycosaminoglycan syntheses were quantified over a 24-hour period. Results-Tendon- and bone marrow-derived cells required 17 to 19 days of monolayer culture to reach 2 passages. Mean SE number of monolayer cells isolated was higher for tendon-derived cells (79 +/- 0.9 X 10(6)) than for bone marrow-derived cells (1.2 +/- 0.1 X 10(6)). Cell numbers after culture for 7 days on acellular tendon matrix were 1.6- to 2.8-fold higher for tendon-derived cells than for bone marrow-derived cells and 0.8- to 1.7-fold higher for IGF-I supplementation than for untreated cells. New collagen and glycosaminoglycan syntheses were significantly greater in tendon-derived cell groups and in IGF-I-supplemented groups. The mRNA concentrations of collagen type I, collagen type III, and cartilage oligomeric matrix protein were not significantly different between tendon- and bone marrow-derived groups. Conclusions and Clinical Relevance-In vitro results of this study suggested that tendonderived cells supplemented with IGF-I may offer a useful resource for cell-based strategies in tendon healing. (Am J Vet Res 201273:153-161)