Effect of insulin-like growth factor 1 and basic fibroblast growth factor on DNA synthesis and collagen production in cultured anterior cruciate ligament cells

This study was undertaken to investigate the effects of insulin-like growth factor 1 (IGF-1) and basic fibroblast growth factor (bFGF) on the DNA and matrix synthesis of cells out-grown from the anterior cruciate ligament (ACL). Five batches of ACL cells from five 8-week-old Japanese white rabbits were isolated and maintained in culture until the fifth passage. We analyzed the effects of various concentrations of IGF-1 (1–1000 ng/ml) on [³H]-thymidine uptake in the cells at the first and fifth passages, and collagen content in the cell layer at the third passage, in the presence or absence of bFGF (10ng/ml). In the absence of bFGF, IGF-1 caused a significant increase in the synthesis of DNA and collagen in the ACL cells. IGF-1 and bFGF, in combination, synergistically increased the DNA synthesis of ACL cells, whereas such synergistic enhancement was not observed in their, collagen production. The amounts of [³H]-thymidine incorporated into the cells incubated with IGF-1 (500ng/ml) and bFGF (10ng/ml) combined were 1.3–1.5 times greater at first passage and 1.3–1.9 times greater at fifth passage than the sum of these with the growth factors used individually. Based on this in vitro finding, we consider it clinically relevant that IGF-1 and bFGF, when used together, have the capability to enhance the primary healing of ruptured ACL. Presented at the 11th Annual Meeting for Orthopaedic Research of the Japanese Orthopaedic Association, Kagoshima, Japan, October 17, 1996.