Tissue plasminogen activator modifies healing of glaucoma filtering surgery in rabbits

The healing response after glaucoma filtering surgery was analyzed immunohistochemically in rabbit eyes that had been treated with tissue plasminogen activator immediately after surgery and in the fellow eyes that had not been so treated. In the untreated eyes, at 1 day after surgery, fibronectin-like immunoreactivity was seen in the scleral fistula tract but not in the subconjunctival space of the filtering bleb. At 3 days immunoreactivity for fibronectin, collagen III, and collagen I could be seen in the bleb and fistula tract. By 14 days staining for collagen I and collagen III filled the surgical site, but fibronectin could only be seen in the fistula tract. In the eyes treated with tissue plasminogen activator immediately after surgery, the deposition of fibronectin and collagen III in the subconjunctival space and fistula tract was apparently delayed and diminished. This delayed and reduced deposition was correlated with the delayed clinical failure of surgery in these eyes. These results suggest that alteration of the biochemical changes in the extracellular matrix occurring after filtering surgery may influence the success of this surgery.