Role Of IL-17 In Diabetic Retinopathy:in-vivo Studies

Background and Aims: Diabetic retinopathy(diabetic retinopathy,DR)is the main complication of diabetic population,which can lead to irreversible visual impairment and is one of the important causes of blindness and incapacity of young and middle-aged people all over the world [1].It has been reported that patients with type 2 diabetes have a 50% or less than60% risk of DR,while patients with type 1 diabetes have a high risk of DR[2].Therefore,it has become a major problem for the development of ophthalmology in China and even the world to deeply study the mechanism of the generation and development of DR and explore new ways to prevent and treat it.At present,the pathogenesis of DR is not clear,it is generally believed that it is mainly composed of microangiopathy,inflammatory reaction and neurodegenerative changes.these factors interact with each other and participate in the pathological process of DR [3,4].During the past decades,a number of studies have suggested that inflammation plays an important role in the generation and development of DR [5-7].Interleukin-17(IL-17,IL-17A)is an inflammatory cytokine involved in the generation and development of some autoimmune and inflammatory-related diseases [8-10],however,what role does it play in the generation and development of DR? It still remains unclear.Therefore,this work is to confirm whether IL-17 can further reveal the signal transduction pathway of retinal Müller cells damaged by IL-17 by affecting the function of retinal Müller cells,and to provide a new perspective for the pathogenesis of DR inflammation.It also provides basic experimental data for the potential clinical application of IL-17 inflammatory signal blocker in the treatment of DR.Methods:In the first part,diabetic mice were induced by intraperitoneal injection of streptozotocin(STZ).Three months later,different concentrations of anti-IL-17 A monoclonal antibody,were injected into vitreous cavity.m Ab or m Ab against IL-17 A receptor.The mice preparing for retinal angiography were killed 2 weeks after intravitreal injection,while the other mice were killed 2 days after intravitreal injection.Analysis of(high performance liquid chromatography analysis,by Western blot,enzyme-linked immunosorbent assay(ELISA)and high performance liquid chromatography Detection and comparison of retinal Müller cells in different treated DR models by HPLC,immunohistochemistry and TUNEL staining.The expression level of various proteins and the apoptosis of ganglion cells;The severity of retinopathy in DR mice was observed by retinal leukocyte adhesion test and retinal angiography.In the second part,Ins2Akita(Akita)male heterozygote mice were able to develop insulin-dependent diabetes on their own.Different doses of mouse recombinant IL-17 A,anti-IL-17 A m Ab or Ad-Act1-sh RNA or Ad-GFP were injected into the vitreous cavity of Akita mice,respectively.By the same method as the first part,the expression levels of various proteins in retinal Müller cells,the apoptosis of ganglion cells and the severity of retinopathy in DR models treated with different treatments were detected and compared.Results: In the first part,the expression of IL-17 A and IL-17 A receptors was up-regulated in the retina of DR induced by STZ,Intravitreal injections with anti-IL-17 A m Ab or anti-IL-17 RA m Ab in DR model mice reduced Müller cell dysfunction,vascular leukostasis,vascular leakage,tight junction protein downregulation and ganglion cell apoptosis in the retina.In the second part,compared with WT mice,the expression of IL-17 A and IL-17 RA in retinal Müller cells was up-regulated and the IL-17RA/Act1/TRAF6/IKK/NF-κ B signaling pathway was enhanced in the diabetic animal model of Akita mice.And IL-17 A will further strengthen the role of the signaling pathway.IL-17 A aggravates the activation and dysfunction of retinal Müller cells,the disintegration of blood-retinal barrier and the apoptosis of retinal ganglion cells in Akita mice through Act1 signaling system.Conclusion: IL-17 exacerbates DR-like pathology by affecting the activation and function of retinal Müller cells,and aggravates Müller cell functional impairment in diabetic mice via IL-17RA/Act1/TRAF6/IKK/NF-κ B pathway.The treatment targeting IL-17,Act1 gene and IKK blocker may provide a new direction for the prevention and treatment of DR in the future.