Clinical evaluation and induced corneal vascularization study by native and anionic collagen membranes in rabbits corneas

Abstract

PURPOSE To evaluate the corneal vascularization (CV) and the clinical aspects induced by interlamellar graft with native (NCM) and anionic (ACM) collagen membranes in rabbits corneas. METHODS An interlamellar graft with a 0.25 x 0.25 cm NCM (group 1) or ACM (group 2) fragment was performed in the right eye (treated eye). In the left eye, an estromal tunnel was done (control eye). Sixteen rabbits were used, and they were subdivided into two experimental groups of eight animals each. The clinical evaluation was performed at the 1st, 3rd, 7th, 15th and 30th postoperative days. Corneal vascularization analysis was performed after 30 days by the Images Analizator System Leica Qwin-550. RESULTS After 7 days, corneal vascularization was observed at about 2.25 +/- 0.71 mm (NCM) and at about 1.0 +/- 1.69 mm (ACM), respectively, from the limbus in direction to the central cornea. After 15 days, CV increased in both groups (5.25 +/- 1.03 mm - NCM; 2.0 +/- 2.39 mm - ACM) and then progressively decreased until day 30 (2.25 +/- 2.10 mm - NCM; 0.75 +/- 2.12 mm - ACM). The statistical analysis indicated that the averages of the distances from the limb vessels to the grafts observed after 7 and 15 days had not differed statistically (p=0.17), and after 15 and 30 postoperative days had a tendency to differ statistically (p=0.09). The control eyes did not present any changes. CONCLUSION The interlamellar graft with native and anionic collagen membranes induced corneal vascularization when applied to rabbit corneas, but anionic collagen membrane induced a smaller corneal vascularization when compared to native collagen membrane. Although further studies are required, the results found in this study demonstrated the usefulness of interlamellar graft with native and anionic collagen membranes in keratoplasties. These membranes consists in one more graft option for the surgical treatment of corneal repair in rabbits and others animals, when other forms of medical and surgical treatment are not effective.