Kaempferol Protects Against Sodium Iodiate-induced Retinal Pigment Epithelial Cells And Retinal Damage By Inhibiting The MAPK And NF-κB Signaling Pathways

Objective To demonstrate that kaemperol has protective effect on sodium iodiate-induced retinal pigment epithelial cells and retinal damage in vitro and in vivo respectively by inhibiting the MAPK signaling pathway and regulating inflammatory factors.Methods In vitro experiments,sodium iodate was added to ARPE-19 cells to establish a damage model,which was divided into control group,model group(SI),and treatment group(kaemperol+SI).Cell viability was detected by MTT assay.Hoechst33342 staining was used to observe the apoptosis.Western blotting was used to detect the expression of MAPK signaling pathway related proteins and inflammatory factors in cells.In vivo experiments were divided into control group,model group(SI),and treatment group(kaemperol+SI).On 1st,7th,14 th,21st days after injection of sodium iodate in mouse,the thickness and morphology change of retina were observed by OCT,on 21 st days by ERG measuring the amplitude of a and b wave to reflect the function of RPE cells,to HE staining to observe the RPE cells and retinal damage,and then discussing kaempferol in AMD’s role in the development.Results In vitro experiment: The absorbance value measured in MTT test was directly proportional to the number of living cells,which could detect the survival and growth of cells,compared with the control group,the measured absorbance value of the kaempferol only group was not reduced,and the safe concentration of kaempferol on RPE cells was 0-100μmol·L-1.The absorbance value of the model group was lower than that of the control group(P<0.05),and that of the treatment group was higher than that of the model group(P<0.05).Hoechst33342 staining showed that the number of apoptotic cells in the model group was higher than that in the control group(P<0.05),and the number of apoptotic cells in the treatment group was lower than that in the sodium iodate model group(P<0.05).Western blotting showed that the ratios of p-ERK1/2/ERK1/2 、 p-p38/p38 、 p-JNK/JNK and the protein expressions of NF-κB、i NOS、TNF-α in the model group were all higher than those in the control group(p <0.05),and the ratios of p-ERK1/2/ERK1/2、p-p38/p38、p-JNK/JNK and the protein expressions of NF-κB、i NOS、TNF-α in the treatment group were lower than those in the model group(p <0.05).This indicated that kaemperol could inhibit the decrease of cell activity,the increase of cell apoptosis,and the phosphorylation of p38,ERK1/2 and JNK,as well as the expression of NF-κB,i NOS,TNF-α caused by the action of sodium iodide.In vivo experiments:OCT showed increased retinal thickness in the treatment group compared to the model group(P<0.05).HE staining showed that,compared with the model group,the retinal thickness of the treatment group increased(P<0.05),the retinal structure was clearer,and the deposition of drusen decreased.ERG showed that the amplitude of wave a and wave b in the model group was lower than that in the control group(P<0.05),and the amplitude of wave a and wave b in the treatment group were higher than that in the sodium iodic model group(P<0.05).Wave a originated from the retinal photoreceptor rods and cones,and wave b originated from bipolar cells,reflecting the functional changes of this specific cell layer.It indicated that kaemperol could improve the morphology and function of RPE cells and retina induced by sodium iodateConclusions Kaempferol protects sodium iodate-induced retinal pigment epithelial cells and retinal damage by inhibiting the MAPK signaling pathway and regulating inflammatory factors.