ABSTRACT
Objective:To explore the effect of myricitrin on the injury of human retinal microvascular endothelial cells (HRMECs) induced by high glucose and its regulation mechanism.Methods:HRMECs were divided into normal control group, high glucose group and 12.5 μg/ml, 25.0 μg/ml and 50.0 μg/ml myricitrin groups.HRMECs transfected with pcDNA and pcDNA-circZNF292, respectively and then cultured in high-glucose medium containing 25 mmol/L D-glucose for 24 hours were assigned as pcDNA group and pcDNA-circZNF292 group.HRMECs transfected with siR-NC and siR-circZNF292, respectively and then cultured in medium containing 50.0 μg/ml myricitrin and 25 mmol/L D-glucose for 24 hours were assigned as myricitrin+ siR-NC group and myricitrin+ siR-circZNF292 group.The cell apoptosis rate was detected by flow cytometry.The concentration of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in cells were detected by enzyme-linked immunosorbent assay (ELISA) kits.The expression levels of circZNF292 and miR-23b-3p were detected by real-time fluorescence quantitative PCR.The targeting relationship between circZNF292 and miR-23b-3p was detected by dual-luciferase reporter assay.The relative expression levels of B-cell lymphoma-2 (bcl-2) and bcl-2-related X protein (bax) were assayed by Western blot.Results:Significant differences were found in the relative expressions of bax and bcl-2 proteins, cell apoptosis rate, MDA concentration, SOD activity, circZNF292 and miR-23b-3p among normal control group, high glucose group and 12.5 μg/ml, 25.0 μg/ml, 50.0 μg/ml myricitrin groups ( F=105.707, 111.835, 74.515, 109.651, 135.020, 219.919, 116.304; all at P<0.001).With the increase of myricitrin concentration, the relative expression levels of bax protein, cell apoptosis rate, MDA concentration and miR-23b-3p in cells gradually decreased, while the relative expression levels of bcl-2 protein, SOD activity and circZNF292 increased, with statistically significant differences among groups with different concentrations of myricitrin (all at P<0.05).In the co-transfected wild-type (WT)-circZNF292 cells, the relative luciferase activity in miR-23b-3p group was 0.35±0.03, which was lower than 0.96±0.09 in microRNA-negative control group, and the difference was statistically significant ( t=11.137, P<0.001).Compared with pcDNA group, the relative expression levels of bcl-2 protein, circZNF292 and MDA concentration in cells of pcDNA-circZNF292 group were significantly increased, and the relative expression levels of bax protein, miR-23b-3p, cell apoptosis rate and SOD activity were significantly decreased (all at P<0.05).The relative expression levels of bax protein, miR-23b-3p, cell apoptosis rate and MDA concentration were reduced and relative expression levels of bcl-2 protein, circZNF292 and SOD activity were enhanced in myricitrin group and myricitrin+ siR-NC group in comparison with high glucose group and myricitrin+ siR-circZNF292 group, showing statistically significant differences (all at P<0.05). Conclusions:Myricitrin can inhibit cell apoptosis and oxidative stress by regulating the expression of circZNF292/miR-23b-3p, thereby reducing the damage of HRMECs induced by high glucose.
ABSTRACT
Objective:To investigate the inhibitory effects of rosmarinic acid (RA) on high glucose-induced angiogenesis of human retinal microvascular endothelial cells (HRMEC) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome pathway-related proteins.Methods:The HRMEC were divided into control group, high glucose group, high glucose+ low concentration RA group, high glucose+ medium concentration RA group, and high glucose+ high concentration RA group, and were cultured in vitro with conventional medium, 30 mmol/L D-glucose medium, 30 mmol/L D-glucose+ 25 μmol/L RA medium, 30 mmol/L D-glucose+ 50 μmol/L RA medium and 30 mmol/L D-glucose+ 100 μmol/L RA medium accordingly.The 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to detect the cell proliferation.Transwell assay was performed to detect the cell migration.Matrigel assay was employed to determine the tube formation ability of cells.Western blot was utilized to detect the expression levels of NLRP3, apoptosis-associated speck like protein (ASC) and cysteinyl aspartate-specific protease-1 (Caspase-1). Enzyme-linked immunosorbent assay (ELISA) kit was used to detect the concentrations of interleukin (IL)-1β and IL-18 in supernatant of cell culture. Results:The cell proliferation rate, the number of migrated cells and the number of formed tubes were (100.00±0.92)%, 37.67±9.02 and 45.00±4.58 in the control group, (163.56±1.46)%, 117.33±7.23 and 95.00±9.54 in the high glucose group, (152.29±2.90)%, 78.67±4.04 and 84.67±1.53 in the high glucose+ low concentration RA group, (147.72±2.22)%, 65.33±4.16 and 71.00±3.61 in the high glucose+ medium concentration RA group, (132.47±0.74)%, 52.67±6.81 and 60.00±1.00 in the high glucose+ high concentration RA group, respectively.There were statistically significant differences in cell proliferation rate, the number of migrated cells and formed tubes among all groups ( F=537.07, 64.63, 45.58; all at P<0.001). Compared with the control group, the cell proliferation rate, the number of migrated cells and formed tubes were significantly increased in the high glucose group, high glucose+ low concentration RA group, high glucose+ medium concentration RA group and high glucose+ high concentration RA group, showing statistical significances (all at P<0.05). Compared with the high glucose group, the cell proliferation rate, the number of migrated cells and formed tubes were significantly decreased in the different concentrations RA groups (all at P<0.05). With the increase of RA concentration, the cell proliferation rate, the number of migrated cells and formed tubes were decreased, and there were statistical differences among high glucose+ low/medium/high concentrations RA groups (all at P<0.05). There were significantly differences in the relative expression levels of NLRP3, ASC and Caspase-1 proteins in cells and the concentrations of IL-1β and IL-18 in cell culture supernatant among all the five groups ( F=145.12, 422.82, 463.79, 2 019.96, 33 406.97; all at P<0.001). Compared with the control group, the relative expression levels of NLRP3, ASC and Caspase-1 proteins as well as the concentrations of IL-1β and IL-18 in cell culture supernatant were significantly increased in the high glucose group, high glucose+ low concentration RA group, high glucose+ medium concentration RA group and high glucose+ high concentration RA group (all at P<0.05). Compared with the high glucose group, the expression levels of NLRP3, ASC and Caspase-1 proteins as well as the concentrations of IL-1β and IL-18 were decreased in the different concentrations RA groups, and the differences were statistically significant (all at P<0.05). With the increase of RA concentration, the expression levels of NLRP3, ASC and Caspase-1 proteins as well as the concentrations of IL-1β and IL-18 were decreased, and there were statistically significant differences among high glucose+ low/medium/high concentrations RA groups (all at P<0.05). Conclusions:RA can inhibit proliferation, migration and tube formation of HRMEC induced by high glucose, and inhibit high glucose-induced activation of NLRP3 inflammasome signaling pathway.