BACKGROUND: Bullous keratopathy has an increasing annual incidence, but its treatment is restricted by few sources of materials for corneal transplantation and high cost of operation. Additionally, some patients who present with serious symptoms have little chance of recovery and low success in corneal transplantation. Amniotic membrane from the corneal stroma has a rich source with low cost, which can effectively relieve the symptoms and improve the quality of life in patients.
OBJECTIVE: To observe the therapeutic efficacy of amniotic membrane implantation into the corneal stroma in the treatment of bullous keratopathy.
METHODS: Forty healthy adult New Zealand rabbits (half male and female) were randomly divided into four groups (A, B, C, D groups), with 10 rats in each group. Rabbit models of bullous keratopathy were made in the groups A, B, C. At 2 weeks after modeling, amniotic membrane implantation into the corneal stroma and corneal surface was performed in groups A and B, respectively, and in group C, corneal lamellar dissection was done but with no amniotic membrane transplantation. In group D, there was no surgical treatment (blank control). A slit lamp microscope with constant crack width and angle of light projection was used to observe the central corneal thickness, and corneal opacification degree, corneal epithelial bulla of rabbits were observed at different time in each group. Under microscope, the rabbit corneal endothelial cells and healing were observed at different time.
RESULTS AND CONCLUSION: At 1 day and 2 weeks after transplantation, the central corneal thickness of rabbits had significant differences in the four groups (P < 0.05). At 4, 8, 12 weeks after transplantation, the central corneal thickness of rabbits showed no difference between groups A and B as well as between groups C and D (both P > 0.05), but there was a significant difference between groups A, B and group C (P < 0.05). At 4 and 8 weeks after transplantation, the degree of corneal opacity was significantly better in group A than the other three groups (P < 0.05). There were obvious scars forming at the incision of rabbits in the group C. Compared with the other three groups, the bulla was improved better in the group A (P < 0.05). At 2 weeks after transplantation, bullous keratopathy relapsed in the group B, and symptoms of edema with bulla were still seen in groups C and D at 12 weeks after transplantation. These findings indicate that amniotic membrane implantation into the corneal stroma can effectively repair rabbit corneal endothelial cells and alleviate the symptoms of edema, but its specific mechanism need to be further studies.