Vitamin C protects against lysophosphatidylcholine-induced expression of monocyte chemoattractant protein-1 in cultured human umbilical vein endothelial cells

Background and Purpose: It is well documented that oxidized low-density lipoproteins (LDLs) can stimulate human vascular endothelial cells to produce monocyte chemoattractant protein-1 (MGP-1). Vitamin C is known to be an important antioxidant for vasodilatation. The purpose of this study was to determine whether pretreatment with vitamin C could protect against oxidized-LDL-induced expression of MCP-1 in cultured human umbilical vein endothelial cells (HUVECs). Methods: Cultured HUVECs were used for desired experiments before passage 4. Lysophosphatidylcholine (lysoPC), an oxidized component of LDL, was designated as the stimulator for MCP-1 synthesis from cultured HUVECs. MCP-1 concentrations in the cultured media were determined by enzyme-linked immunosorbent assay. MCP-1 RNA was evaluated by a semi-quantitative reverse transcriptase-polymerase chain reaction. Results: HUVECs secreted MCP-1 within 30 minutes after exposure to 50 μM lysoPC. Compared with samples treated with lysoPC alone, pretreatment with vitamin C in concentrations of 50, 100, 150, and 200 μM, reduced levels of MCP-1 in the culture medium by 44%, 51%, 60%, and 67%, respectively, while levels of MCP-1 mRNA decreased by 15%, 18%, 80%, and 82%, respectively. Conclusions: Our findings imply that pretreatment with vitamin C can suppress lysoPC-induced expression and secretion of MCP-1 in cultured HUVECs. Therefore, vitamin C is protective against lysoPC-mediated inflammatory insults to the vascular endothelium in vitro.