Effects of oxidized low-density lipoprotein on relaxation function and fenestrae regulation in human liver sinusoidal endothelial cells

Abstract

Objective To investigate the effect of oxidized low-density lipoprotein(oxLDL) on the relaxation function and fenestrae regulation in human liver sinusoidal endothelial cells(HLSECs). Methods Cells were treated with 100 mg/L oxLDL(oxLDL group). Meanwhile, the normal group was established and untreated. After incubation of HLSECs for 24 h, real time quantitative reverse transcription- polymerase chain reaction (qRT - PCR) and Western blotting were used to detect the mRNA and protein expression of endothelial nitric oxide synthase(eNOS), endothelin-1(ET-1) and caveolin-1(Cav-1) in HLSECs. The fenestra morphology, number and distribution in the cells were visualized by using scanning electron microscopy. Data were analyzed with t test. Results Compared with the those in control, the mRNA expression of ET-1 and Cav-1 overexpressed by 2.62- and 2.49-folds(2.62±0.32 vs 1.00±0.00 and 2.49±0.27 vs 1.00±0.00), and the protein expression of ET-1 and Cav-1 overexpressed by 2.31- and 2.96-folds(1.34±0.10 vs 0.58±0.03 and 0.71 ±0.03 vs 0.24±0.02) in oxLDL group, respectively; the mRNA and protein expression of eNOS significantly decreased by 45% and 54% (0.55 ±0.12 vs 1.00± 0.00 and 0.34±0.02 vs 0.74± 0.04) in response to oxLDL versus control(t=32.54, 26.62, 6.29, 16.71, 22.09, 15.20, all P<0.05). The fenestra morphology of HLSECs has changed obviously in oxLDL group, oxLDL caused a significant decrease in the porosity, diameter and number of fenestrae compared with those in the control group, even the fenestrae were disappeared in some regions. Conclusions oxLDL can upregulate the expression of ET-1 and Cav-1, downregulate the expression of eNOS. These effects promote the process of relaxation dysfunction and defenstration of HLSECs. Key words: Oxidized low-density lipoprotein; Liver sinusoidal endothelial cells; Relaxation function; Fenestrae