Abstract
Purpose :
We have previously found that desonide disodium phosphate (DES) at low concentrations (i.e. 0.025%) appears to retain a significant anti-inflammatory activity on the ocular surface while sparing intraocular structures in a model of endotoxin-induced uveitis. Here, we sought to challenge our previous findings and investigated whether a formulation of xanthan gum (XNT) 0.2% containing DES 0.025% could reduce corneal damage in murine model of dry eye.
Methods :
Thirthy-two C57BL/6 female mice (8–12 w) were subjected for 7 days to a controlled environment with low humidity (20% RH) and constant airflow (20 l/min). A scopolamine patch (0.75 mg) was applied to the animals’ tails and renewed after 3 days. Naïve animals (CTRL-) were kept in standard housing conditions (50%–60% RH). Of the animals inside the chamber, positive control animals (CTRL+) were left untreated while the remaining groups received 10 µl q.i.d of eyedrops containing either 0.2% XNT alone or XNT 0.2% plus DES 0.025%. Fluorescein staining of the cornea was evaluated by slit lamp with a standardized grading system at baseline (t = 0) and after 3 and 7 days of treatment. Data represent the mean±s.d. of scores assigned to 8 mice per group. Statistics were by one-way ANOVA plus Bonferroni post-test.
Results :
Observations at day 3 showed that corneal staining of CTRL+ mice (5.7±2.3) was significantly worsened (p<0.001) with respect to CTRL- (1.5±1). Treatment with XNT 0.2% did not produce any remarkable amelioration over CTRL+, while XNT 0.2% plus DES 0.025% significantly reduced corneal score to 3.5±1.7 (p<0.05, vs CTRL+). Observations at day 7 showed that corneal scores of CTRL+ mice remained mostly unchanged in comparison to day 3. Conversely, in mice treated with XNT 0.2% either alone or in combination with DES 0.025% corneal damage was significantly reduced by 44±17 (p<0.05) and 69±18 (p<0.01), respectively.
Conclusions :
Eyedrops containing XNT were shown to reduce corneal damage caused by iposecretive/evaporative stress in a model of dry eye in mice. Notably, the addition of DES 0.025% to XNT eyedrops improved the effect exerted by XNT alone by producing an earlier onset of the protective action on corneal epithelium. These findings support the hypothesis that a low concentration of DES may have ancillary action to that of XNT in the treatment of inflammatory ailments of the ocular surface.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.