Abstract
Abstract: :
Purpose:To evaluate the cellular reaction around a new aqueous shunt after implantation in rabbit eyes. This device has a microporous structure and was developed to direct the flux of aqueous humor to the subconjunctival space. Methods:Nine pigmented rabbits weighing 2.0 to 2.6 Kg were operated on for a regular trabeculectomy procedure. The feet of the aqueous shunt were placed through the fistula into the anterior chamber angle and the device was covered with the scleral flap. Four rabbits were anesthetized and sacrificed 1 month after the surgery, 2 rabbits after 2 months and 3 rabbits were sacrificed 3 months postoperatively. All the eyes were enucleated and fixed by immersion in 10% neutral buffered formalin. After dehydration and embedding in paraffin, the globes were sectioned and stained with hematoxylin-eosin, Periodic acid-Schiff and Masson’s trichrome stains. The sections were then examined under a light microscope (Olympus, Optical Co. Ltd., Japan). The histological examination focused on the cellular reaction of the anatomical structures of the anterior chamber angle and on the formation of fibrous tissue (encapsulation) of the shunt in the anterior chamber and subconjunctival space. Results:Postoperative dislocation of the device was observed in some rabbits because of the size of the device being relatively large for the rabbit eye. One month postoperatively, a low-grade cellular infiltrate (monocytes) and fibroblasts, and some newly formed capillaries were observed around the shunts. After 2 and 3 months, the histopathological findings were compatible with a low-grade foreign-body reaction, composed of epithelioid cells and occasional foreign-body giant cells. Significant fibrous tissue formation with encapsulation of the device was not observed. Conclusion:This new aqueous shunt was designed to be implanted during a regular trabeculectomy. Our preliminary results suggest that significant fibrous tissue formation and encapsulation around the devices does not occur.
Keywords: 444 intraocular pressure • 601 trabecular meshwork • 316 animal model