维生素D与癌症: 研究现状和展望

  目的  探讨铁对大鼠血清25-（OH）D₃、1，25-（OH）₂D₃水平以及大鼠肾脏维生素D受体（VDR）表达的影响。  方法  30只刚断乳雄性SD大鼠适应性喂养7 d，按体重随机分为对照组（n = 6）和模型组（n = 24），对照组大鼠饲喂正常饲料，模型组饲喂缺铁饲料，连续6周。造模成功后将模型组大鼠按血红蛋白（Hb）水平随机分为缺铁组、低、中和高铁组，每组6只；对照组与缺铁组大鼠灌胃生理盐水，低、中和高铁组大鼠分别给予11、33和99 mg/kg的右旋糖酐铁灌胃；连续4周后，8 % 水合氯醛麻醉大鼠，腹主动脉取血，分离血清，取动物肾脏组织， – 80 ℃冻存备用；采用酶联免疫试剂盒法检测大鼠血清25-（OH）D₃、1，25-（OH）₂D₃水平，生化试剂盒法检测大鼠肾脏组织铁含量，Western blot和免疫组化法检测大鼠肾脏维生素D受体（VDR）蛋白表达水平。  结果  与对照组比较，造模后模型组大鼠Hb水平降低，差异有统计学意义（P < 0.05）；与缺铁组比较，低、中和高铁组大鼠Hb水平明显升高（P < 0.05）；与对照组比较，缺铁组大鼠血清中25-（OH）D₃、1，25-（OH）₂D₃水平下降，VDR蛋白表达水平降低，差异有统计学意义（P < 0.05）；与缺铁组比较，低、中和高铁组大鼠血清中25-（OH）D₃、1，25-（OH）₂D₃水平升高，差异有统计学意义（P < 0.05）；随着干预铁的浓度增加，VDR蛋白的表达呈逐渐上调趋势。  结论  机体铁含量影响VD₃的活化以及肾脏VDR蛋白的表达。

Association between vitamin D receptor (FokI) genetic variant rs2228570 and iron profile in hemodialysis patients

  Objective  To investigate the effect of iron on serum 25-hydroxyvitamin D3 (25-(OH)D₃), 1,25-dihydroxyvitamin D3 (1,25-(OH)₂D₃) and the expression of vitamin D receptor (VDR) in rat kidney.   Methods   With 7 days′ adaptive feeding, thirty newly weaned male Sprague-Dawley (SD) rats were randomly divided into a control group (n = 6) and a model group (n = 24) according to body weight. The rats in the control group were fed with normal diet and those in the model group were fed with iron deficiency diet for 6 weeks. After successful modeling, the rats in model group were randomly divided into four group (6 rats in each group) with iron deficiency, and low, moderate and high iron according to hemoglobin (Hb) content. The rats in the control group and the iron deficiency group were given normal saline, and the rats in the low, moderate and high iron groups were given iron dextran at dosages of 11, 33 and 99 mg/kg by gastric gavage, respectively. After 4 weeks, the rats were anesthetized with 8% chloral hydrate. Blood samples of the rats were collected from the abdominal aorta for serum isolation and kidney tissue specimens were collected and stored at – 80 ℃ for later detections. Serum 25-(OH)D₃ and 1,25-(OH)₂D₃ were detected with enzyme-linked immunosorbent assay (ELISA) kit method. Renal tissue iron content of the rats was measured with biochemical kit method. Protein expression of vitamin D receptor (VDR) in the rats′ kidney was determined with Western blot and immunohistochemistry method.   Results   The model rats′ Hb was significantly lower than that of the control rats (P < 0.05); the Hb of the rats in low, moderate and high iron groups were significantly increased compared to that of the rats in the iron deficiency group (all P < 0.05). Significantly decreased serum 25-(OH)D₃/1,25-(OH)₂D₃ and VDR in kidney were detected in the rats of iron deficiency group contrasting to those of the rats in control group (P < 0.05 for all). In the rats of low, moderate and high iron groups, serum 25-(OH)D₃ and 1,25-(OH)₂D₃ increased significantly (P < 0.05 for all) and with the increases of serum 25-(OH)D₃ and 1,25-(OH)₂D₃, the VDR in kidney was gradually up-regulated in comparison with those in the rats of iron deficiency group.   Conclusion  In rats, iron content affects the activation of VD₃ and the expression of VDR protein in kidney.