The Effect And Mechanism Of IL-1Ra On Diabetic Corneal Epithelium Wound Healing

Purpose:Patients with diabetes mellitus(DM)often develop corneal complications and delayed wound healing.Interleukin-1β(IL-1β)involves in normal acute wound healing,as well as pathogenesis and low grade inflammation state of diabetes.Interleukin-1 receptor antagonist(IL-1Ra)blocks the signaling of IL-1β.How diabetes might alter innate immune/acute inflammatory responses to tissue injury,leading to delayed wound healing,and the role of IL-1β and IL-1Ra in diabetic wound healing remain mostly elusive.In this study,by investigating these unknown,we evaluated the therapeutic potential of IL-1Ra in diabetic corneal complications and explored the mechanism.Methods:1.Normal and streptozotocin-induced type 1 diabetic mice were used to assess theexpressions of Interleukin-1β(IL-1β)and IL-1Ra in homeostatic and healing corneas.2.Their role in mediating epithelial wound healing was defined by antibodyneutralization or siRNA downregulation.3.Exogenous IL-1Ra were used to treat diabetic delayed corneal wound healing.Ki-67,TUNEL,pAKT,NIMP-R14,NK1.1 and TUJ-1 were stained to assess apoptosis,proliferation,infiltration of neutrophils and natural killer cells as well as nerveregeneration in the corneas of normal and diabetic mice,respectively.4.Protein Array was performed and verified to identify related cytokines andchemokines of Interleukin-1 receptor(IL-1R)signaling in healing corneal epithelia.Resluts:1.The wound-induced expression of IL-1Ra,but not IL-1β,was suppressed in diabeticcorneas.2.In normoglycemic mice,IL-1β or IL-1Ra blockade delayed wound healing.3.Local administration of recombinant IL-1Ra significantly increased ki-67 expressionin corneal epithelial cells,decreased TUNEL staining,induced AKT Phosphorylation,increased cells numbers of NIMP-R14 and NK1.1 postive cells and increased TUJ-1stained nerve fiber density and length.4.C-X-C motif chemokine 10(CXCL10)level was downregulated in diabetic healingcorneas and restored by exogenous IL-1Ra treatment.CXCL10 was a chemokinerelated to IL-1R.Exogenous CXCL10 alleviated delayed wound healing in thediabetic but attenuated it in the normal corneas.Conclusions:The suppressed early innate/inflammatory responses instigated by imbalance between IL-1β and IL-1Ra is an underlying cause for delayed wound healing in the diabetic corneas.In addition to delayed reepithelization,diabetes weakened PI3K-AKT signaling,caused cell apoptosis,diminished cell proliferation,suppressed neutrophil and natural killer cell infiltrations,and impaired sensory nerve re-innervation in healing mouse corneas.Local administration of recombinant IL-1Ra partially but significantly reversed these pathological changes in the diabetic corneas.Local application of IL-1Ra accelerates wound closure of diabetic healing cornea.CXCL10 was involved in IL-1Ra mediated diabetic wound healing.