Department of Food Science and Nutrition, College of Life Sciences, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
Department of Anatomy, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait.
Nutrients. 2018 Feb 26;10(3):264. doi: 10.3390/nu10030264.
A negative association between blood lead and vitamin D concentrations has been reported, however, experimental data on the effect of lead (Pb) on vitamin D metabolism is scarce. We investigated the effects of Pb on serum vitamin D metabolites, vitamin D activating enzymes and vitamin D receptor (VDR) in rats. Newborn Wistar rat pups were exposed to 0.2% Pb-acetate via their dams' drinking water from post-natal day (PND) 1 to 21 and directly in drinking water until PND30. Serum 25-hydroxyvitamin D was analyzed with LC-MS/MS and 1,25-dihydroxyvitamin D with an immunoassay. Tissue expression of vitamin D activating enzymes and VDR were measured by Western blot and immunohistochemistry. Serum 25-hydroxyvitamin D was significantly decreased at both PND21 and PND30, whereas 1,25-dihydroxyvitamin D was decreased ( < 0.05) only at PND21 in the Pb-exposed rats. Expression of renal 1-α-hydroxylase was decreased by Pb only at PND21 ( < 0.05) but the brain 1-α-hydroxylase was not affected. Hepatic 25-hydroxylase expression was significantly decreased at PND21 but significantly increased at PND30 by Pb exposure. VDR expression in the brain was increased at both PND21 and PND30 ( < 0.05). These results suggest that Pb interferes with vitamin D metabolism by affecting the expression of its metabolizing enzymes.
已有研究报道血液铅浓度与维生素 D 浓度之间呈负相关，但关于铅（Pb）对维生素 D 代谢影响的实验数据却很少。我们研究了 Pb 对新生 Wistar 大鼠血清维生素 D 代谢物、维生素 D 激活酶和维生素 D 受体（VDR）的影响。从出生后第 1 天（PND）到第 21 天，新生大鼠通过母鼠饮用水摄入 0.2%的醋酸铅，然后直接在饮用水中摄入至 PND30。通过 LC-MS/MS 分析血清 25-羟维生素 D，通过免疫测定法分析 1,25-二羟维生素 D。通过 Western blot 和免疫组织化学法测量维生素 D 激活酶和 VDR 的组织表达。血清 25-羟维生素 D 在 PND21 和 PND30 时均显著降低，而 1,25-二羟维生素 D 仅在 PND21 时在 Pb 暴露组中降低（<0.05）。Pb 仅在 PND21 时降低肾脏 1-α-羟化酶的表达（<0.05），但脑 1-α-羟化酶不受影响。肝 25-羟化酶表达在 PND21 时显著降低，但在 PND30 时因 Pb 暴露而显著增加。脑 VDR 表达在 PND21 和 PND30 时均增加（<0.05）。这些结果表明，Pb 通过影响其代谢酶的表达来干扰维生素 D 代谢。
