天然和氧化型极低密度脂蛋白对巨噬细胞胞内游离钙浓度的影响

The Effects of Native and Oxidized Very Low Density Lipoprotein on intracellular Free Calcium Concentration in Macrophages

为了更好地阐明极低密度脂蛋白，尤其是氧化型极低密度脂蛋白在动脉粥样硬化发病过程中的作用机制，本文利用双波长显微分光光度计，检测了天然和氧化型极低密度脂蛋白对巨噬细胞内游离钙浓度（［Ｃａ２＋］ｉ）的影响。结果显示，极低密度脂蛋白和氧化型极低密度脂蛋白均能刺激巨噬细胞［Ｃａ２＋］ｉ升高。极低密度脂蛋白可增加巨噬细胞［Ｃａ２＋］ｉ的５７％，而氧化型极低密度脂蛋白则增加巨噬细胞［Ｃａ２＋］ｉ的１１５％。这表明极低密度脂蛋白和氧化型极低密度脂蛋白均可通过引起巨噬细胞［Ｃａ２＋］ｉ升高而介导细胞的一系列生物学功能，但后者的作用比前者更强。这与氧化型极低密度脂蛋白能明显促进巨噬细胞的生物学功能，包括迁移和分泌细胞因子相一致。

Aim To well understand the mechanism of native and oxidized very low density lipoprotein (VLDL) and OVLDL) in the atherogenesis, we investigated the influences of VLDL and OVLDL on intracellular free calcium concentration ([Ca2+]i).Methods Very low density lipoprotein was isolated from normal blood donors by density gradient ultracentrifugation, and oxidized by CuCI2 with a final concentration of 10 μmol/L. Rabbit peritoneal exudate macrophages were collected. For determination of [Ca2+]i , fura-2 fluorescence and microfluorimetry were used.Results Both VLDL and OVLDL significantly increased [Ca2+]i in macrophages. VLDL induced an increase of 57% in [Ca2+]i , where as OVLDL induced an increase of 115% in [Ca2+]i.Conclusions It suggests that VLDL and OVLDL induce many biological functions by stimulating increase of [Ca2+]i in macrophages, but the latter are more stronger than the former. This corresponds to the fact that OVLDL induces stronger biological functions including migration and secreting cytokines.