Effect of local application of basic fibroblast growth factor on ligament healing in rabbits.

OBJECTIVE

The effect of basic fibroblast growth factor (bFGF) on healing of a 4-mm defect in the medial collateral ligament of rabbits was studied.

METHODS

Fibrin gel containing 0 (vehicle only), 0.1, 1, or 10 micrograms of recombinant human bFGF was applied to the defect during the surgical procedure. Controls did not receive fibrin gel. Four rabbits in each group were sacrificed 1, 2, 3, and 6 weeks after surgery. Repair tissues were subjected to gross and histologic examinations, and expression of type I procollagen messenger RNA was evaluated using in situ hybridization after 2 and 3 weeks.

RESULTS

bFGF promoted formation of repair tissue and was associated with early filling of the ligament defect. Tissue maturation was significantly delayed after 3 and 6 weeks in the high-dose bFGF groups. In the low dose group, in contrast, tissue maturation was similar to that in controls at all time points, by both gross and histologic examination. In situ hybridization studies showed that type I procollagen mRNA expression was reduced in all bFGF groups.

CONCLUSION

Our data demonstrate that a single local application of bFGF promoted early formation of repair tissue in injured medial collateral ligaments. High doses of bFGF reduced repair tissue maturation, suggesting that in clinical uses the dose may play a significant role.