摘要Icariin,a flavonoid glycoside,is extracted from Epimedium.This study aimed to investigate the vascular protective ef-fects of icariin in type 1 diabetic rats by inhibiting high-mobility group box 1(HMGB1)-related inflammation and exploring its poten-tial mechanisms.The impact of icariin on vascular dysfunction was assessed in streptozotocin(STZ)-induced diabetic rats through vas-cular reactivity studies.Western blotting and immunofluorescence assays were performed to measure the expressions of target pro-teins.The release of HMGB1 and pro-inflammation cytokines were measured by enzyme-linked immunosorbent assay(ELISA).The results revealed that icariin administration enhanced acetylcholine-induced vasodilation in the aortas of diabetic rats.It also notably re-duced the release of pro-inflammatory cytokines,including interleukin-8(IL-8),IL-6,IL-1β,and tumor necrosis factor-alpha(TNF-α)in diabetic rats and high glucose(HG)-induced human umbilical vein endothelial cells(HUVECs).The results also unveiled that the pro-inflammatory cytokines in the culture medium of HUVECs could be increased by rHMGB1.The increased release of HMGB1 and upregulated expressions of HMGB1-related inflammatory factors,including advanced glycation end products(RAGE),Toll-like re-ceptor 4(TLR4),and phosphorylated p65(p-p65)in diabetic rats and HG-induced HUVECs,were remarkably suppressed by icariin.Notably,HMGB1 translocation from the nucleus to the cytoplasm in HUVECs under HG was inhibited by icariin.Meanwhile,icariin could activate G protein-coupled estrogen receptor(GPER)and sirt1.To explore the role of GPER and Sirt1 in the inhibitory effect of icariin on HMGB1 release and HMGB-induced inflammation,GPER inhibitor and Sirt1 inhibitor were used in this study.These inhib-itors diminished the effects of icariin on HMGB1 release and HMGB1-induced inflammation.Specifically,the GPER inhibitor also negated the activation of Sirt1 by icariin.These findings suggest that icariin activates GPER and increases the expression of Sirt1,which in turn reduces HMGB1 translocation and release,thereby improving vascular endothelial function in type 1 diabetic rats by in-hibiting inflammation.