锌缺乏及补锌对小鼠胚胎HOX3.5基因表达的影响

为研究锌缺乏及补锌对小鼠胚胎HOX3 5基因表达的影响 ,将昆明种雌性小鼠随机分为缺锌组(ZD)、缺锌后补锌组 (ZR)和常锌对照组 (ZN)。ZD组及ZR组喂饲含锌量为 (3 0± 0 5 )mg kg的缺锌饲料 ,但ZR组小鼠从孕第 7天开始改喂含锌量为 30mg kg的常锌饲料。ZN组小鼠一直食用常锌饲料。经 2 5天喂养后 ,与同系成年雄鼠交配。于妊娠第 12天时处死动物 ,并立刻剖腹取出胎鼠。用地高辛标记的探针 ,采用原位杂交方法检测小鼠胚胎HOXC4(3 5 )基因mRNA在鼠胚冰冻切片上的表达量。结果发现 :ZD、ZR组HOX3 5基因阳性表达的面密度及其平均光密度明显低于ZN组 (P <0 0 5 )。提示 :锌缺乏时可导致HOX3 5基因表达量下降 ,这种调控作用乃发生在胚胎发育的早期 ,从孕早期 (孕 7天 )开始补锌仍无法纠正

Effect of zinc deficiency and zinc replenishment on HOX3.5 gene expression in mouse embryos

The effect of zinc deficiency and zinc replenishment on HOX3.5 gene expression in mouse embryos was investigated. Sixty Kunming female mice (25-30 g) were divided into three groups: zinc-deficient groups (ZD), zinc-replenished group (ZR) and zinc normal controlled group (ZN). ZD mice fed with ZD diet (Zn 3.0 +/- 0.5 mg/kg), ZN mice fed with ZN diet (Zn 30 mg/kg), and ZR mice fed with ZD diet at first and then with ZN diet from the 7th day of pregnancy. After feeding different diet for 25 days, the mice were made to copulate (female: male = 2:1). At the 12th day of pregnancy, the mice were killed and the embryos were stored at -70 degrees C. The content of mRNA of HOX3.5 in the embryos were determined by in situ hybridization with digxigenin-labeled cDNA probes. The result showed that the expression on area density and L-density (average optical density) of Hox3.5 in ZD and ZR groups were decreased in comparing with those in ZN group (P < 0.05). It was suggested that the decreased HOX3.5 gene expression by zinc deficiency might influence the normal growth of mouse embryos, and this effect might occurr in the early stage of embryo development, which can not be prevented by replenishing zinc at the 7th day of pregnancy.