Abstract
Purpose: :
The Purpose of this study was to investigate the influence of amniotic membrane transplantation (AM) with our without mesenchymal stem cell (MSC) transplantation on corneal woundhealing after severe corneal burn.
Methods: :
MSC were isolated from 3 weeks old female Lewis rats and cultured until passage 4. Then, they were analyzed for their marker profile by flow cytometry and used for experiments. Those were as follows: 12 weeks old rats were anaesthetized and a corneal burn was done in one eye using 0.1N NaOH for 1 min. After intense rinsing with water the rats were divided into 4 treatment groups: 1st group no intervention, 2nd group lid suture, 3rd group double layer of AM sutured onto the cornea + lid suture, 4th group 1 layer of AM covered with MSC plus a second layer of AM on top of the first sutured onto the cornea + lid suture. The ocular surface was evaluated every 3-4 days for 4 weeks. Each week, rats of all groups were euthanized and corneal mRNA expression of acute inflammatory and angiogenic cytokines was analyzed.
Results: :
In ocular surface evaluation, rats in group 2, 3 and 4 showed a significantly faster epithelialisation (p<0,001) and less corneal opacity than group 1 (p<0,05). There was no difference between group 2-4 concerning these parameters. Corneal vaskularisation did not significantly differ between group 1- 4. mRNA expression of the MMP-2 and TSP1- gene peaked 2 weeks after the injury in group 1 while the treated groups showed lower or no up-regulation. IL-6 showed a strong up-regulation after 1 week in group 2-4, while up-regulation in the control group (group 1) occurred after 3 weeks. Concerning VEGF-expression, there was slight up-regulation throughout the follow-up in all 4 groups with no significant differences.
Conclusions: :
Treatment groups showed significantly better clinical outcome than the control (group 1). Interestingly, there was no significant difference between the treatment groups regarding our clinical outcome measures. MSC or AM transplantation did not further improve the clinical outcome in comparison to lid suture alone. These results correlated with the regulation of the gene expression. Future studies using AM and MSC in the acute phase after corneal burn may either use later time points after injury or repeated transplantation of AM +/- MSC in order to check for more beneficial effects of these treatments.
Keywords: wound healing • cornea: epithelium • neovascularization