EFFECT OF GROWTH-FACTORS ON THE PROLIFERATION OF FIBROBLASTS FROM THEMEDIAL COLLATERAL AND ANTERIOR CRUCIATE LIGAMENTS

Growth factors have been shown to stimulate fibroblast division and th us may influence Ligament healing. We analyzed the effects of individu al growth factors on the proliferation of fibroblasts from the medial collateral and anterior cruciate ligaments of the rabbit in vitro in o rder to identify growth factors that might enhance proliferation of fi broblasts and to compare the responses of the fibroblasts from the two Ligaments to these growth factors. Through measurement of the uptake of [H-3]-thymidine into DNA, fibroblasts from these ligaments that had been treated with epidermal growth factor and basic fibroblast growth factor were found to proliferate nearly eight times more than control fibroblasts. Additionally, the fibroblasts of both ligaments prolifer ated at similar rates when exposed to platelet-derived growth factor-A A, platelet-derived growth factor-BB, basic fibroblast growth factor, insulin-like growth factor-1, and interleukin-1-alpha. However, epider mal growth factor and transforming growth factor-beta caused the fibro blasts from the medial collateral ligament to proliferate at a rate 1. 3-1.4 times greater than that of fibroblasts from the anterior cruciat e ligament. The reverse was true with acidic fibroblast growth factor, which stimulated the fibroblasts from the anterior cruciate ligament to proliferate at a rate 1.3-1.6 times greater than that of fibroblast s from the medial collateral ligament. This study demonstrated that gr owth factors can stimulate cell division in ligaments and may be effec tive in enhancing ligament healing but that these differences were not great enough to explain fully the clinical differences observed betwe en healing of the medial collateral and anterior cruciate ligaments.