Abstract
Purpose: :
To analyze the effect of topical Cyclosporine on corneal nerve regeneration after lamellar flap surgery in murine corneas.
Methods: :
A 2.0 mm lamellar corneal flap was created in Thy-1 YFP murine neurofluorescent corneas (n=20) using a preset 50 um diamond blade for initial incision and a Grieshaber UltraVit spatula for lamellar dissection. Mice were divided into study group and control group with n=10 in each group. Study group received Cyclosporine 0.1% eye drops twice a day and control group received Optive eye drops, twice daily for 6 weeks each. Using Stereolumar microscope, sequential in vivo images were taken at baseline, 2 weeks, 4 weeks and 6 weeks. Maximum intensity projection of z-stacks were used to calculate nerve fiber length density, neurite extension and corneal T-cell infiltration. Neurite extension was calculated as percent increase in nerve fiber density between weeks 6 and week 2, using Neurolucida software. YFP+ T-cells were enumerated in the cornea.
Results: :
In the control group, mean nerve fiber length density at 2 weeks and 6 weeks was 15.151mm/mm2 and 21.123 mm/mm2, respectively, while in study group mean nerve fiber length density at 2 weeks and 6 weeks was 12.95 mm/mm2 and 16.734 mm/mm2, respectively. Neurite extension increased by 41.04% (+/- 0.14) over a period of 4 weeks in control group and by 28.27% (+/- 0.07) in the study group. Average number of YFP+ T-cell infiltrates observed in the control group at 2 weeks and 6 weeks were 8 and 9, respectively and1 and 1 in the study group. Neurite extension and T-cell infiltration was significantly lower in the study group (p<0.05).
Conclusions: :
Cyclosporine inhibits inflammatory cell infiltration as well as retards the nerve regeneration in uncomplicated lamellar flaps. Mild T-cell infiltration may be facilitative towards nerve regeneration.
Keywords: cornea: basic science • cornea: stroma and keratocytes • regeneration