Interleukin 17A(IL17A)is reported to be involved in many inflammatory processes,but its role in aortic valve diseases remains unknown.We examined the role of IL17A based on an ApoE-/-mouse model with strategies as fed with high-fat diet or treated with IL17A monoclonal antibody(mAb).12 weeks of high-fat diet feeding can elevate cytokines secretion,inflammatory cells infiltration and myofibroblastic transition of valvular interstitial cells(VICs)in aortic valve.Moreover,diet-induction accelerated interleukin 17 receptor A(IL17RA)activation in VICs.In an IL17A inhibition model,the treatment group was intra-peritoneally injected with anti-IL17A mAb while controls received irrelevant antibody.Functional blockade of IL17A markedly reduced cellular infiltration and transition in aortic valve.To investigate potential mechanisms,NF-κB was co-stained in IL17RA+VICs and IL17RA+macrophages,and further confirmed by Western blotting in VICs.High-fat diet could activate NF-κB nuclear translocation in IL17RA+VICs and IL17RA+macrophages and this process was depressed after IL17A mAb-treatment.In conclusion,high-fat diet can lead to IL17A upregulation,VICs myofibroblastic transition and inflammatory cells infiltration in the aortic value of ApoE-/-mice.Blocking IL17A with IL17A mAb can alleviate aortic valve inflammatory states.