Oxidized Low Density Lipoprotein Induced the Injury of Endothelial Cells Via Lectin-Like Oxidized Low Density Lipoprotein Receptor-1

Aim To explore the injured effects of endothelial cells by oxidized low density lipoprotein and its mechanism via lectin-like ox-LDL receptor-1. Methods The specific ox-LDL receptor of cultured umbilical vein endothelial cells (hUVEC) was examed by their binding of 125 I-labeled ox-LDL and by the inhibiting effects of competitors on ox-LDL binding to Lectin-like ox-LDL receptor-1 (LOX-1). Lactate dehydrogenase (LDH) was determined by the method of 2,4-dinitryl-benzohydrazine. Cell viability were detected by trypan blue dye and observed under phase-difference microscope. Results hUVEC membrane was observed to possess a high-affinity ox-LDL binding site (Determined by Scatchard plot, its Kd is 38.4±18.8 mg/L and Bmax is 181.5±55.5 ng/10 6cells). Incubation of hUVEC with ascending dose of ox-LDL for 24 hours. The ascending doses of ox-LDL significantly increase LDH leakage into culture media (from 0.111±0.012 ku/g protein to 0.770±0.044 ku/g protein). Accordingly, viability of hUVEC decrease in response to ox-LDL (from 95.6%±3.8% to 80.7%±4.9%). The effects of ox-LDL is blocked partially by LOX-1 chemical blockers, polyinosinic acid and carrageenan. Conclusion hUVEC possess endothelial receptors for ox-LDL (LOX-1). Ox-LDL-mediated injury to hUVEC may be induced by LOX-1.