沉默调节因子相关酶1(SIRT1)对近视豚鼠脉络膜血管密度及内皮素-1表达的影响OA

Objective To investigate the regulatory effect of sirtuin 1(SIRT1)on choroidal vascular density in the lens-induced myopia(LIM)models of guinea pigs and explore its potential molecular mechanisms.Methods The lens in-duction method was used to establish a myopia model in the left eye(experimental eye)of guinea pigs,with the right eye as the self-control eye.The LIM group and blank control group were set up,respectively.Immunofluorescence staining was performed to evaluate the changes in choroidal vascular density after modeling.Choroidal endothelial cells in primary guinea pigs were isolated and purified using the density gradient centrifugation method.The cells were divided into the control group[treated with dimethyl sulfoxide(DMSO)],the SIRT1 agonist group(treated with SRT1720+DMSO),and the SIRT1 inhibitor group(treated with EX527+DMSO).The cell counting kit-8 cytotoxicity experiment screened the optimal concen-tration of cell drugs(the optimal concentrations of SRT1720 and EX527 were 12.5 μmol·L-1 and 10.0 μmol·L-1,respec-tively).Flow cytometry was used to detect the expression levels of reactive oxygen species(ROS)in choroidal tissue and in vitro cells of guinea pigs.Real-time fluorescence quantitative polymerase chain reaction,enzyme-linked immunosorbent assay,and Western blot were used to measure the mRNA and protein expression levels of SIRT1,endothelin-1(ET-1),and hypoxia-inducible factor-1α(HIF-1α)in choroidal tissue and in vitro cells of guinea pigs.Results Compared with the blank control group,the LIM group showed a significant reduction in choroidal vascular fluorescence signal and vascular density,a significant increase in ROS expression levels in the choroidal tissue and the mRNA and protein expression levels of ET-1 and HIF-1α,and a significant decrease in the expression level of SIRT1 protein,and the differences were statistically significant(all P＜0.05).Compared with the control group,the SIRT1 inhibitor group showed increased expression levels of ROS,ET-1 mRNA and protein in cells,while the SIRT1 agonist group showed decreased expression levels of ROS,HIF-1αmRNA and protein,and SIRT1 protein in cells,and the differences were statistically significant(all P＜0.05).Compared with the SIRT1 agonist group,the SIRT1 inhibitor group showed a decrease in both SIRT1 mRNA and protein expression lev-els in cells and an increase in the mRNA and protein expression levels of ET-1 and HIF-1α,and the differences were statisti-cally significant(all P＜0.05).The Western blot analysis results showed that there were statistically significant differences in the expression of SIRT1,ET-1,and HIF-1α proteins in the choroidal tissue and cells of guinea pigs in each group(all P＜0.05).Conclusion The decrease in choroidal vascular density in myopic guinea pigs is related to the downregulation of SIRT1 expression in the choroidal tissue.Its mechanism may be that the downregulation of SIRT1 expression leads to in-creased oxidative stress in choroidal endothelial cells,and accumulated ROS stabilizes and activates HIF-1α protein to drive ET-1 expression,ultimately leading to choroidal vascular dysfunction and reduced blood perfusion.