The Effect Of OxHDL₃ On Tissue Type Plasminogen Activator Expression In Human Umbilical Vein Endothelial Cells

OBJECTIVETo investigate the change of tissue type plasminogen activator expression induced by oxidized high density lipoprotein 3 and the preliminary mechanisms involved.METHODSHUVECs were incubated with oxHDL3 at different concentrations 0 10 2040 80 120 mg/L and different time(0 6 12 24 48h). t-PA mRNA and protein expression were determined by RT-PCR , ELISA and immunocytochemistry, respectively. Western blot detected the phosphorylation of p38 MAPK and assay of NF- B p65 in the nuclear.HUVECs were pre-treated with p38 MAPK inhibiter(SB203580) and NF- B inhibiter BAY11-7085 to investigate the mechanisms.RESULTS1: Compared with the 0mg/ L oxHDL3 group, oxHDL3 can decrease the expression of t-PA mRNA. The t-PA production decrease most significantly in the group using 80 mg/L oxHDL3 treated for 24 hours.oxHDL3 caused a significantly decreased t-PA mRNA expression by 30% and 19%, at the level of 80mg/L respectively (P<0.05).The result of ELISA show that oxHDL3 can also decrease the expression of t-PA protein. The t-PA production decrease most significantly in the group using 80 mg/L oxHDL3 treated for 24 hours.oxHDL3 caused a significantly decreased t-PA protein expression by 34% and 35%, at the level of 80mg/L respectively (P<0.05). The result of immunocytochemistry show that compared with the control group, oxHDL3 caused a significantly decreased t-PA protein expression by 40% and 42%, at the level of 80mg/L respectively (P<0.05).2: Compared with the control group and HDL3 group, oxHDL3 can increase thephosphorylation of p38 MAPK and the assay of NF- B p65 in the nuclear. Compared with the control group, the phosphorylation of p38 MAPK and the assay of NF- B p65 increase by 40% and 45% , at the level of 80mg/L respectively (P<0.05). Compared withHDL3 (80mg/L)group,increase by 22% and 31% , at the level of 80mg/L respectively (P<0.05).3: Compared with oxHDL3 (80mg/L)group, the expression of t-PA mRNA and proteinincrease significantly (P<0.05) in the group which pre-treated with p38 MAPK inhibitor(SB203580) and NF- B inhibitor BAY11-7085 .CONCLUSIONS1.oxHDL3 can inhibit the expression of t-PA mRNA and protein in human umbilical vein endothelial cells .2.The inhibitory effect on tPA mRNA and protein expression induced by oxHDL3 may have relationships with p38 MAPK and NF- B signaling pathways.