Fibroblast growth factor and epidermal growth factor receptors in ligament healing

Although recent in vivo studies indicate that basic fibroblast growth factor hastens the healing and strength of the medical collateral ligament after injury, in vitro studies with epidermal growth factor and basic fibroblast growth factor have shown increased fibroblast proliferation with the exogenous administration of these growth factors. Using an established spontaneously healing rabbit injury model, the surgical transection of the medial collateral ligament was undertaken in 12 anesthetized male adult rabbits. Immunohistochemical localization using monoclonal antibodies to the basic fibroblast growth factor receptor and epidermal growth factor receptor were used to identify the distribution and relative concentrations of the individual receptors at 3, 7, 14, and 28 days after surgery. Realizing that the trophic effects of basic fibroblast growth factor and epidermal growth factor are determined exclusively by their individual receptors, this study confirms the hypothesis that basic fibroblast growth factor and epidermal growth factor receptor proteins are present and increase during the early stages of medial collateral ligament healing. The understanding of this rabbit ligament injury model has far reaching implications to ligament healing seen in humans. By elucidating the spatial and temporal regulation of the basic fibroblast growth factor and epidermal growth factor receptor proteins, exogenous growth factor therapy, once approved for human use, potentially can be synchronized with maximal protein receptor levels.