The source of fibronectin in corneal wound healing was investigated in rabbits by inducing experimental bullous keratopathy using benzalkonium chloride. The location of fibronectin was detected by indirect immunofluorescent microscopy. One day after irrigation with benzalkonium chloride, no endothelial cells were found and epithelial damage was observed. Specific fluorescence for fibronectin was observed at the limbal area, which suggests the vascular origin of fibronectin, and at the stromal side of Descemet's membrane. On day 3, endothelial healing became active. Fibronectin from limbal circulation was much more prominent than at day 1, and it diffused into the central portion of the cornea. Both the endothelial and stromal side of Descemet's membrane stained for fibronectin. On day 7, fibronectin from limbal circulation decreased, as did fibronectin in the stroma. Retrocorneal membrane was observed and stained strongly for fibronectin. Our study demonstrates that fibronectin was released from limbal blood vessels and diffused into the stroma, and that endothelial cells may synthesize fibronectin during the healing process.
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