Abstract
Purpose:
Following corneal epithelial abrasion, the co-dependent recruitment of neutrophils and platelets is beneficial to wound healing. In general, inhibition of neutrophil recruitment limits not only platelet recruitment but also delays healing. However, topical application of IL-20 inhibits neutrophil recruitment without delaying wound closure. Whether platelet recruitment is normal under these conditions and accounts for the normal rate of wound closure is unclear. The purpose of this study was to evaluate the effect of IL-20 on platelet recruitment after corneal epithelial abrasion in the mouse.
Methods:
Adult female C57BL/6 mice were anesthetized. A golf-club spud was used to make a 2mm central corneal abrasion. Over a 24h period, once every 4h, wounded mice were given topical applications of recombinant mouse IL-20 (rIL-20) dissolved in phosphate buffered saline (PBS) (200ng/mL) and control mice received PBS. Corneas were prepared for immunofluorescence microscopy and the number of infiltrating neutrophils and platelets was determined. Some injured corneas were cultured for 6h in the presence of rIL-20 to evaluate CXCL1 chemokine levels using an ELISA kit.
Results:
Topically applied rIL-20 resulted in a 70% reduction in platelet and neutrophil recruitment as compared to PBS (p<0.05). The inhibition of recruitment was comparable for intravascular and extravascular platelets. The neutrophil chemoattractant, CXCL1, was significantly elevated after corneal abrasion at 6h post-injury and this increase was inhibited by 67% in the presence of rIL-20.
Conclusions:
In the injured cornea, IL-20 suppresses neutrophil and platelet recruitment while epithelial wound healing is sustained. The reduction in CXCL1 expression after IL-20 treatment likely explains the inhibition of neutrophil and platelet recruitment since platelet recruitment is tightly linked to neutrophil recruitment. Collectively, the data suggest IL-20 maybe a potential therapeutic for suppressing inflammation while supporting corneal epithelial wound healing.
Keywords: 480 cornea: basic science •
765 wound healing •
557 inflammation