Dexamethasone Drug Eluting Nanowafers Control Inflammation in Alkali-Burned Corneas Associated With Dry Eye

PURPOSE. To evaluate the efficacy of a controlled release dexamethasone delivery system for suppressing inflammation in an ocular burn + desiccating stress (OB+DS) model. METHODS. Nanowafers (NW) loaded with Dexamethasone (Dex, 10 mu g) or vehicles (2.5% Methylcellulose; MC) were fabricated using hydrogel template strategy. C57BL/6 mice were subjected to unilateral alkali ocular burn with concomitant desiccating stress for 2 or 5 days and topically treated either with 2 mu L of 0.1 % Dex or vehicle four times per day and compared with mice that had MC-NW or Dex-NW placed on their corneas. Clinical parameters were evaluated daily. Mice were euthanized after 2 or 5 days. Quantitative PCR evaluated the expression of inflammatory cytokines IL-beta and IL-6 and matrix metalloproteinases (MMP) in whole cornea lysates. Myeloperoxidase activity (MPO) was measured using a commercial kit in cornea lysates. RESULTS. Both Dex drop and Dex-NW groups had significantly lower corneal opacity scores compared with their vehicles. Both Dex drops and Dex-NW significantly decreased expression of IL-1 beta, IL-6, and MMP-9 RNA transcripts compared with vehicle drops or wafers 2 and 5 days after the initial lesion. A significant lower number of neutrophils was found in both Dex treatment groups and this was accompanied by decreased MPO activity compared with vehicle controls. CONCLUSIONS. Dex-NW has efficacy equal to Dex drops in preserving corneal clarity and decreasing expression of MMPs and inflammatory cytokines of the corneas of mice subjected to an OB+DS model.