ZINC-DEFICIENCY DOES NOT ENHANCE LDL UPTAKE BY P-388 D1 MACROPHAGES IN-VITRO

The aim of the study was to investigate the effect of zinc depletion o n the susceptibility of Wistar rat low-density lipoproteins (LDL) to p eroxidation and their uptake by macrophages, before and after in vitro oxidation. The rats were fed for 7 wk a Zn-adequate diet (100 ppm) ad libitum (AL), a Zn-deficient diet (0.2 ppm) ad libitum (ZD), or a Zn- adequate diet according to the pair-feeding method (PF). Zinc status w as determined and, for each group, blood was pooled, and LDL were isol ated and labeled with (125)Iodine. An aliquot of each LDL sample was o xidized using Fe-II 10 mu M/ascorbate 250 mu M. Oxidized and nonoxidiz ed (native) LDL were incubated with P 388 D1 macrophages, and their ra tes of uptake and degradation by macrophages were measured. Before oxi dation, LDL uptake and degradation were not modified by the diet, sugg esting that Zn deficiency did not modify rat LDL in vivo. After oxidat ion, both LDL uptake and degradation were significantly enhanced in th e three groups. Nevertheless, we did not observe a significant effect of Zn deficiency. This observation suggests that, in our experimental conditions, Zn deficiency did not modify LDL catabolism.