Tendon healing in vitro: Promotion of collagen gene expression by bFGF with NF-κB gene activation

Abstract

Purpose: Matrix synthesis of intrasynovial tendon cells and activation of nuclear transcription factors are pivotal to promotion of flexor tendon healing. We investigated the effects of basic fibroblast growth factor (bFGF) on synthesis of type I collagen and activation of nuclear transcription factor κB (NF-κB) in an in vitro culture model of intrasynovial tenocytes. Method: Tenocytes obtained from explant culture of rabbit intrasynovial tendon segments were treated with bFGF at concentrations of 0, 2, and 10 ng/mL. Expression of type I collagen and NF-κB genes was determined by quantitative analysis of products of reverse-transcription polymerase chain reactions. Proliferation of the cells was assessed by incorporation of bromodeoxyuridine into the DNA of the cells. Results: Expression levels of type I collagen and NF-κB genes of tenocytes were increased significantly by bFGF. Cell proliferation as indicated by DNA labeling was promoted significantly by bFGF. Expression of the NF-κB gene increased proportionately to the amounts of bFGF stimulating the cells and was correlated with increases in proliferation rate of tenocytes. Conclusions: Results of this study show that expression of type I collagen and NF-κB genes is promoted manifestly by bFGF. The effects were proportionate to in vitro proliferation rates of tenocytes. The study indicated that matrix synthesis of flexor tendons can be promoted by bFGF and that NF-κB may play a pivotal role in initiating proliferation and type I collagen synthesis of tenocytes. (J Hand Surg 2003;28A:215-220. Copyright © 2003 by the American Society for Surgery of the Hand.)