In vivo binding of topically applied human bFGF on rabbit corneal epithelial wound.

We present the results of the first evaluation of human placenta extracted basic fibroblast growth factor (bFGF) in a rabbit corneal epithelium wound-healing model. Healing dose-response experiments after selective epithelial wounding with iodine vapors demonstrated that bFGF accelerated the repair process in a saturable manner. Corneal binding of topically applied 125I-labeled bFGF was investigated using radioassay and autoradiographic techniques. Basic FGF was shown to bind specifically to denuded epithelial basement membrane in a very stable fashion and not to the intact epithelium. No transfer of the topical bFGF to the aqueous humor or any intraocular structure could be observed. The stability of this interaction was further demonstrated by reextracting and characterizing the labeled factor from treated corneas. The specificity of the fixation was documented by in vivo topical competition with unlabeled bFGF or heparin. We propose that bFGF-basement membrane interactions play a role in corneal wound healing.