Paracetamol inhibits copper ion-induced, azo compound-initiated, and mononuclear cell-mediated oxidative modification of LDL.

The effects of paracetamol and sodium salicylate on the susceptibility of LDL to oxidative modification were studied. LDL was subjected to Cu(2+)-, azo compound-, or peripheral blood mononuclear cell-initiated oxidation in the absence and presence of paracetamol and salicylate. Paracetamol (100 mumol/L; 25 micrograms LDL/mL) reduced the rate of formation of conjugated dienes and the amount of conjugated dienes formed during Cu(2+)-induced oxidation by 67% and 58%, respectively. Paracetamol (400 mumol/L; 100 micrograms LDL/mL) reduced the generation of lipid peroxides during Cu(2+)-induced oxidation by 43% (P < .05), the relative electrophoretic mobility in agarose gels by 16% (P < .05), and the amount of oxidized LDL taken up by J774 macrophages by 22% (P < .05). Paracetamol (100 mumol/L; 100 micrograms LDL/mL) reduced the 2,2'-azobis-(2-amidinopropane hydrochloride)-initiated lipid peroxidation by 70% (P < .05) and the relative electrophoretic mobility by 34% (P < .05). Paracetamol (100 mumol/L; 100 micrograms LDL/mL) reduced the amount of lipid peroxides generated in LDL during mononuclear cell-mediated oxidation by 69% (P < .01) and the relative electrophoretic mobility by 38% (P < .01). In comparison, 10 mumol/L alpha-tocopherol reduced the amount of lipid peroxides formed during cellular LDL oxidation and the relative electrophoretic mobility by 52% and 65%, respectively (P < .05). In the absence of paracetamol, SOD and catalase inhibited the modification of LDL (P < .05), suggesting that superoxide anions and hydrogen peroxide might be involved in the cell-mediated modification pathway. In the presence of paracetamol, SOD showed no additional inhibitory effect.(ABSTRACT TRUNCATED AT 250 WORDS)