Corneal protein repair after amniotic membrane photo-tissue bonding versus amniotic membrane graft in the treatment of corneal ulcer (an experimental study)

Corneal alkali burns persist as a significant challenge in our field, often leading to a prolonged treatment course with various sight-threatening problems. This work, of utmost importance, aimed to apply the photo-tissue bonding technique (PTB) to weld the amniotic membrane (AM) to the corneal surface versus an amniotic membrane graft (AMG) and explore its safety in saving corneal protein against alkali burn.Methods Twenty-seven rabbits with an induced corneal ulcer using 1 mol/L NaOH solution. Nine rabbits were used as an ulcer group without treatment, and the rest (n = 18) were subjected to two treatment protocols with AM. The first was attaching the AM to the corneal ulcer through photo-tissue bonding using 532 nm and rose Bengal stain as a photosynthesizing agent. The second was using cyanoacrylate glue as a tissue adhesive. The corneal total protein (TP), refractive index (RI), DNA fragmentation, and oxidative stress index (OSI) were evaluated. Results: The cornea's TP showed a significant decrease (p˂0.001) immediately, 1 week, and 2 weeks after ulcer induction (-58.9%, -64.4%, and - 72.6%, respectively). The treatment with AM PTB showed improvement immediately (-45.2%, p˂0.001), after one week (-27.4%, p˂0.01), and after two weeks (-14.38%, p˂0.05). Moreover, the treatment with AMG showed improvement after the same periods with percentage changes of -52.05%, (p˂0.001), -41.8% (p˂0.001), and - 32.2%, (p˂0.01) with respect to the control. Moreover, RI of corneal protein showed improvement after two weeks of treatment with AM PTB (3%, p˃0.05) and AMG (7%, p˃0.05), respectively. The corneal protein DNA base pairs improved 88.49% for AM PTB and 82.35% for the AMG group. The oxidative stress was shifted towards an antioxidative state in AM PTB (-3.9%, P > 0.05) and the AMG group (15.9%, P < 0.05). Conclusion: The AM PTB technique used in corneal ulcers showed promising improvement in total corneal proteins, refractive index, DNA fragmentation, and OSI than AMG using cyanoacrylate glue. These results strongly support the use of AM PTB for ophthalmic purposes, suggesting its potential to enhance clinical research and practice for patients with corneal ulcers and ocular surface diseases.