Protective Effects And Mechanisms Of Naringenin Administration In Animal Models Of Retinal Injury

Objective:This study was designed to investigate the neuroprotective effect of naringenin administration on the acute retinal Ischemia/reperfusion(I/R)model and chronic Ocular hypertensive(OHT)model,and the possible mechanism involved.To provide a new therapeutic drugs or dietary supplements and potential therapeutic targets for the prevention or treatment of glaucoma or related diseases in which neuroinflammation is a key pathogen.Methods:In this study,male C57BL/6 mice(6-8 weeks)were used as experimental subjects.Intraocular pressure(IOP)was increased in the right eye for 1 hour followed by subsequent perfusion to establish the right acute retinal I/R model.The chronic OHT model was established by injecting microbeads into the anterior chamber of the right eye.In both models,the left eyes were the control(CON)groups.During the experiment,mice were given vehicle,naringenin(NAR)at low concentration(100mg/kg/ day)or high concentration(300 mg/kg/ day).According to the difference in model and administration,they were divided into the CON groups: CON+vehicle,CON+100 NAR,and CON+300 NAR group,and experimental groups: I/R(OHT)+Vehicle,I/R(OHT)+100 NAR,and I/R(OHT)+300 NAR group.Hematoxylin eosin(HE)staining,RBPMS,and glial fibrillary acidic protein(GFAP)immunofluorescen-ce staining were used to evaluate retinal damage degree of I/R and OHT injury.The expression levels of GFAP,CD38,Sirtuin1(SIRT1),and NOD-like receptor protein 3(NLRP3)were detected by Western blotting(WB)to explore their mechanism of action.Results:In the OHT model,microbeads induced an increase in IOP in the right eye,and both high and low concentrations of naringenin reduced IOP at different stages.However,in the cumulative IOP comparison,only high concentrations of naringenin show significant IOP reduction.The thickness of the GCL,the number of cells in the GCL,and the number of RGCs labeled by RBPMS are significantly reduced after injury,in both the I/R and OHT models.High concentrations of naringenin inhibited retinal thickness thinning and cell count reduction caused by the microbead and I/R.A high concentration of naringenin also reduces RGCs loss in the whole retina,induced by the I/R model and the OHT model.A lower concentration of naringenin only improves RGCs loss in the peripheral retina induced by the I/R model.At the same time,high concentrations of naringenin significantly inhibit astrocyte activation and reduce the expression of GFAP protein in the retina.In addition,high concentrations of naringenin inhibited the increased expression of NLRP3 and CD38 proteins induced by I/R and OHT damage,while upgrading the expression of the SIRT1 protein.Conclusion:This study is the first to show that naringenin can reduce IOP elevation induced by microbead in the OHT model,providing a novel idea for the application of naringenin in the treatment of glaucoma.Naringenin protected retinal GCL thickness and cell counts,and RGCs survival in the I/R model and the OHT model.The mechanism may be that naringenin inhibits the activation of retinal astrocytes and mediates the CD38/SIRT1 signaling pathway,which plays an anti-inflammatory role.Naringenin may be a potential therapeutic drug or dietary supplement for the prevention and treatment of glaucoma.