氧化型低密度脂蛋白诱导巨噬细胞凋亡

Oxidized low density lipoproteins induce apoptosis in macrophages 1

氧化型低密度脂蛋白诱导巨噬细胞凋亡牛喜林，张修武，郭兆贵（湖南医科大学分子药理研究室，长沙４１００７８，中国）关键词ＤＮＡ片断；细胞凋亡；低密度脂蛋白；腹腔巨噬细胞目的：研究氧化型低密度脂蛋白（ｏｘＬＤＬ）诱导巨噬细胞凋亡．方法：超速离心法分离人血...

IM: To examine whether oxidized low density lipoproteins (ox LDL) might induce apoptosis in mouse peritoneal macrophages (MPM). METHODS: Low density lipoproteins (LDL) were isolated from healthy human plasma by ultracentrifugation and oxidized by CuSO 4 10 μmol·L -1 . MPM were incubated in a medium containing ox LDL, LDL, or phosphate buffer solution (PBS) as control. DNA fragmentation was visualized by agarose gel electrophoresis and determined quantitatively using Hoechst 33258 fluorochrome. RESULTS: Ox LDL, not LDL, elicited typical apoptotic morphological changes (shrinkage of cytoplasm and condensation of chromatin) and DNA fragmentation in a time and dose dependent manner. Incubation for 24 h was necessary for ox LDL 200 mg protein ·L -1 to induce DNA fragmentation, and the maximal effect reached at 72 h. The DNA fragmentation after 24 h incubation with ox LDL at concentrations of 100, 200, and 400 mg protein·L -1 amounted to 6 0 % ( P >0 05), 9 3 % ( P <0 05), and 30 9 % ( P <0 01) , respectively vs PBS control. Dextran sulfate, a scavenger receptor blocker and cycloheximide, a protein synthesis inhibitor, exhibited no effect on DNA fragmentation. However, antioxidant butylated hydroxytoluene (BHT) 20 μmol·L -1 completely inhibited Cu 2+ mediated oxidation of LDL as well as the apoptosis inducing effect of Cu 2+ exposed LDL. Lysophosphatidylcholine (LPC), an active component in ox LDL, at concentration up to 60 μmol·L -1 , did not elicit DNA fragmentation in MPM. CONCLUSION: Ox LDL induces apoptosis in MPM without involving LPC.