Title High fat-induced upregulation of LOX-1 expression in RF/6A cells with high glucose

Abstract

AIM: To investigate the effect of oxidized low-density lipoprotein (ox-LDL) on the expression of lectin-like receptor of ox-LDL (LOX-1) and intercellular adhesion molecule-1 (ICAM-1) in the monkey choroid-retinal endothelial cell line RF/6A under high-glucose conditions. METHODS:RF/6A cells were grown in normal or high-glucose (25 mM) medium for 2 days. In parallel, RF/6A cells were grown in medium with high glucose and ox-LDL (25 or 50 μg/ml) or normal medium with ox-LDL (50 or 75 μg/ml), the concentrations of which were determined by initial screening based on migration and immunofluorescence. LOX-1 and ICAM-1 expression was determined by western blot analysis. The maximal effect on RF/6A cells was observed with a concentration of 25 mmol/l glucose and incubation for 48 h. Based on the immunofluorescence assay, the expression of LOX-1 was upregulated under high glucose compared with that under normal glucose and more pronounced with a glucose concentration of 50 μg/ml. Western blot indicated significant LOX-1 overexpression and blocked ICAM-1 activation under high-glucose conditions with or without ox-LDL in RF/6A cells.RESULTS: In the normal glucose+ox-LDL group (50 and 75 μg), LOX-1 expression increased as compared with that in the control group (P<0.01 and P<0.05, respectively). In the high glucose group (25 and 50 μg), expression of LOX-1 and ICAM-1 increased as compared with that in the control group (P>0.05 and P>0.01, respectively). CONCLUSION:These findings indicated that a certain concentration of ox-LDL blocks high-glucose-induced retinal vascular endothelial injury by inhibiting the upregulation of ICAM-1 expression due to a high-glucose environment. Thus, dyslipidemia may play an important role in the development of diabetic retinopathy, emphasizing the importance of active regulation of blood lipids in diabetic retinopathy therapy.