Experimental Study Of The Effect Of Oxidized Low Density Lipoprotein On Macrophages

Objective: To investigate the effect of oxidized low density lipoprotein(ox LDL) on macrophages and their secretion of macrophage migration inhibitory factor(MIF). As well as the clinical significance of MIF.Methods:(1) Preparation of monocytes derived macrophages(MDMs), co-culture with ox LDL at concentrations of 25ug/ml, 50ug/ml, and 75ug/ml, respectively. MDMs cultured without ox LDL were normal controls(NC). MDM proliferation was detected using cell counting kit-8 assay(CCK-8 assay); supernatant MIF was examined using ELISA.(2) Preparation of MDMs derived from THP-1 cell lines which were transfected with NF-?B-LUC plasmids, co-culture with ox LDL as above-mentioned, NF-?B pathway activity was tested by luciferase test.(3) MDMs containing NF-?BLUC plasmids were co-cultured with ox LDL, self-control study was performed at the same concentration of ox LDL, with or without adding NF-?B pathway inhibitor BAY 11-7082 at the concentration of 10 u M to culture medium. Supernatant MIF was detected. Shp65-MDMs were constructed to verify the importance of NF-?B pathway.(4) The evaluation of MIF serum level in patients with post inventional restenosis.Results:(1) Compared with NC, significantly increased MDM proliferation occurred 12 hours after co-culture with ox LDL, the proliferation increased by 17.7%, 27.8% and 41.2%, respectively at 48 hours(P<0.001); supernatant MIF level increased simultaneously, reaching 1.49,1.67 and 2.09 folds, respectively at 48 hours, as compared with NC(P<0.001).(2) Compared with NC, significant activation of NF-?B pathway was detected 12 hours after co-culture with ox LDL, the activation was increased by 38.1%, 60.3% and 61.1%, respectively at 48 hours(P<0.001).(3) Compared with NF-?B pathway inhibitor BAY 11-7082-free group, supernatant MIF level decreased significantly at 12 hours in BAY 11-7082 group, it decreased by 58.6%, 69.3%, 69.7% and 73.5%, respectively at 48 hours(P<0.001).(4) The MIF serum level in restosis patients triumphed that in healthy people and first admission ASO patients.Conclusions: ox LDL at concentrations of 25 to 75ug/ml could promote MDM proliferation and MIF secretion, this effect was enhanced with prolonged co-culture time. The increased MIF secretion induced by ox LDL might be achieved through activation of the NF-?B pathway. Serum MIF level might somehow relate to the occurrence of post interventional restenosis.