Objective: To study the mechanism of intraocular pressure (IOP) decline after allogeneic transplantation of trabecular meshwork (TM) in primate experimental glaucoma.
Methods: The experimental open-angle glaucoma models were created in 8 rhesus monkey eyes by repeated pangoniophotocoagulation on functional TM using argon laser. After 2, 3, 5 months respectively, avidin-gold or self-erythrocytes, which acted as tracers of the aqueous humor outflow, were perfused into the anterior chamber under normal pressure and volume conditions. 30 minutes later, 2.5% glutaraldehyde was perfused into the anterior chamber under the same conditions. Allograft TMs and photocoagulated area (serving as the control) were observed by light, transmission, scanning electron microscopy and ultrahistochemistry study.
Results: The IOP of 5 eyes of 6 experimental eyes became normal. A blood reflux into Schlemm's canal was seen by gonioscopy in 4 eyes. The surface of TMs from graft showed the normal uveal TM cords and intertrabecular spaces. Erythrocytes were found in the intertrabecular spaces and Schlemm's canal. Avidin-gold and vacuolar containing gold were observed in the cells of TM and Schlemm's canal. The TMs of photocoagulated area appeared to be fewer and narrower intertrabecular spaces. The uveal cords of this zone were confused. The content of acid mucopolysaccharides in the grafts was closer to normal than that in the photocoagulated areas.
Conclusion: TM of allogeneic transplantation not only can survive but also function as an aqueous humor outflow pathway. We consider that this operative procedure can be used for treatment of some cases with glaucoma cautiously.