Task: Question Answering
Input (English): Context: It is well documented that oxidized low-density lipoproteins (LDLs) can stimulate human vascular endothelial cells to produce monocyte chemoattractant protein-1 (MCP-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).', '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.', 'HUVECs secreted MCP-1 within 30 minutes after exposure to 50 microM lysoPC. Compared with samples treated with lysoPC alone, pretreatment with vitamin C in concentrations of 50, 100, 150, and 200 microM, 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.\Question: Does vitamin C protect against lysophosphatidylcholine-induced expression of monocyte chemoattractant protein-1 in cultured human umbilical vein endothelial cells?
Output (English): 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.