Objective To explore the effect of SB431542 on monkey choroidal-retinal endothelial (RF/6A) cells in high glucose state and its mechanism of regulating mitochondrial autophagy by mediating the PINK1/Parkin pathway. MethodsCell experiments. The minimum effective drug concentration of SB431542 was determined by using the Cell Counting Kit-8 (CCK-8). RF/6A cells cultured in vitro were divided into normal group (NC group), mannitol group, high glucose group (HG group), high glucose with dimethyl sulfoxide group (HG + DMSO group), and high glucose + SB431542 group (HG + SB431542 group). CCK-8 and cell scratch assay were used to detect the proliferation and migration of RF/6A cells induced by high glucose. The expression of autophagosomes was detected by autophagy staining kit; the expression level of reactive oxygen species was detected by reactive oxygen species kit; the expression level of mitochondrial superoxide in cells was detected by MitoSOX fluorescent probe; the mitochondrial membrane potential level in cells was detected by JC-10 staining; the morphology of mitochondria was observed by MitoTracker staining, and the total area of mitochondria, average shape factor and branch length were quantitatively analyzed.Cellular immunofluorescence (IF) staining was used to detect the fluorescence expression of EndMT markers vimentin and VE-cadherin; Western blotting (WB) was used to detect the protein expression of vimentin, VE-cadherin, and mitochondrial autophagy-related proteins TOMM20, LC3, P62, PINK1, and Parkin; one-way analysis of variance was used for comparisons among multiple groups.ResultsThe minimum effective drug concentration of SB431542 was 5 μmol/L. SB431542 significantly inhibited the proliferation and migration of RF/6A cells induced by high glucose (F = 81.92、87.84, P＜0.000 1). SB431542 suppressed the expression of reactive oxygen species and mitochondrial superoxide induced by high glucose (F = 429.50, 450.20; P＜0.000 1), restored the mitochondrial membrane potential level (F = 315.3, P＜0.000 1), and restored the mitochondrial morphology (F = 209.50, P＜0.000 1). IF and WB confirmed that SB431542 inhibited the expression of Vimentin induced by high glucose (F = 117.30、51.11; P＜0.000 1) and upregulated the expression of VE-cadherin (F = 136.80、27.54; P＜0.000 1). WB further confirmed that SB431542 upregulated the protein expression of LC3, PINK1, and Parkin (F = 16.64, 37.72, 32.63; P＜0.05) and inhibited the protein expression of TOMM20 and P62 (F = 33.87, 67.77; P＜0.01). ConclusionSB431542 upregulates mitochondrial autophagy expression through activation of the PINK1/Parkin pathway, effectively restores mitochondria-related functions to maintain homeostasis, and inhibits high glucose-induced RF/6A cell proliferation,migration,and EndMT formation.