Use of a gel biopolymer for the treatment of eviscerated eyes: experimental model in rabbits

Abstract

Purpose: To evaluate histologically the integration process of cellulose gel produced by Zoogloea sp when implanted into rabbits' eviscerated eyes. Methods: This experimental study employed 36 eyes of 18 rabbits subjected to evis ceration of their right eyes. The sclerocorneal bag was sutured and filled with biopolymer from sugar cane in the gel state. All animals were clinically examined by biomicroscopy until the day of their sacrifice which occurred on the 7 th , 30 th , 60 th , 90 th , 120 th , or 240 th day. The eyeballs obtained, including the left eyes considered controls were sent for histopathological study by optical macroscopy and microscopy. Tissue staining techniques used included hematoxylin-eosin, Masson trichrome (with aniline), Gomori trichrome, Van Gienson, Picrosirius red, and periodic acid-Schiff (PAS). Results:No clinical signs of infection, allergy, toxicity, or extrusion were observed throughout the experiment. The corneas were relatively preserved. Macroscopic examination revealed a decrease of ~ 8% in the volume of the bulbs implanted with the biopolymer. After cutting, the sclerocorneal bag was solid, compact, elastic, and resistant to traction, with a smooth and whitish surface, and showed no signs of necrosis or liquefaction. The episcleral tissues were somewhat hypertrophied. The histological preparations studied in different colors revealed an initial lymphoplasmacytic infiltration, replaced by a fibroblastic response and proliferation of histiocytes, along with formation of giant cells. Few polymorphonuclearneutrophils and eosinophils were also found. Neovascularization and collagen deposition were present in all animals starting from day 30; although on the 240 th day of the experiment the chronic inflammatory response, neovascularization and collagen deposition had not yet reached the center of the implant. Conclusion: In this model, the cellulose gel produced by Zoogloea sp proved to be biocompatible and integrated into the orbits. Morphometric, immunohistochemical and biodegradability studies should be performed in the future. Keywords

The biopolymer sugarcane as filling material of critical defects in rats

“…Comparative observational studies in animals between the polymer and other materials, commonly used in humans, showed biopolymer superiority, although even without data for completion of statistical studies 18,19 .…”

Biocompatibility of the bacterial cellulose hydrogel in subcutaneous tissue of rabbits

“…The bacterial cellulose presented a high biocompatibility in the three cytotoxicity assays 2. Bacterial cellulose has demonstrated effectiveness as a conductor cell and inducing the healing process 3-6. It has also been used in different areas of surgery such as urethral reconstruction 7 , bio-sling for treatment of urinary incontinence 8,9 , bulking agent in orthopedics, ophtalmology and urology [10][11][12] . Patches in the femoral vein 13 , mesh as an anti-adherent barrier in peritoneal surgery have also been used 14 .…”

Effect of sugarcane biopolymer in vocal fold of rabbits. Comparative study with calcium hydroxyapatite

“…In both cases collagen deposition maintained the integrity of the dura mater and volume of the eye 17,18 . This finding suggests that the mass effect achieved by the injection of SCB may persist after the resorption of the polymer.…”

“…In both cases the SCB was replaced by collagen fibers, which retained at least partially the mass effect of the substance on the applied site 17,18 . In a recent work, Leão et al 19 studied the inflammatory reaction caused by the injection of the vocal fold SCB in rabbits.…”