Abstract:

This work aimed to investigate the effect of endoplasmic reticulum stress (ERS) on accelerating vascular
endothelial cell injury under glucosamine treatment, and to study whether quercetin improves the cell damage and function via
regulating ERS related molecules. Human umbilical vein endothelial cells (HUVEC) were exposed to 15 mmol/L glucosamine
to induce cell injury. Different groups of HUVEC cells were created by the following treatments: 15 mmol/L mannitol as
isotonic control, 5 μg/mL tunicamycin as positive control group, 15 mmol/L glucosamine and varying doses of quercetin
(5, 10, 20, 50 μmol/L and 100 μmol/L). The cell survival rate, the concentrations of ICAM-1, VCAM-1 and ET-1 in culture
supernatants, the expression of ERS and apoptosis related molecules were determined. Compared with the normal control
group, glucosamine significantly suppressed cell growth, and increased the concentrations of ICAM-1 and ET-1 (P ＜ 0.05).
In addition, it upregulated the expression levels of ERS and apoptosis related proteins in HUVEC cells. However, quercetin (especially
at the dose of 20 μmol/L) significantly reduced concentrations of ICAM-1 and ET-1 (P ＜ 0.05), downregualted the expression
levels of ERS and apoptosis related proteins and the cell proliferation was enhanced. Glucosamine might promote and aggravate
vascular endothelial cell injury by activating ERS while quercetin might improve vascular endothelial cell by inhibiting ERS
signal pathway which may reduce inflammation and apoptosis.

Key words: human umbilical vein endothelial cells (HUVEC), endoplasmic reticulum stress (ERS), glucosamine, quercetin