膳食补锌对胎盘及母鼠小肠金属硫蛋白MT-1和MT-2mRNA表达的影响

EFFECT OF ZINC SUPPLEMENTATION ON EXPRESSION OF METALLOTHIONEINS MT-1 AND MT-2 mRNA IN PLACENTA AND SMALL INTESTINE OF PREGNANT RATS

目的:探讨孕期膳食补锌对大鼠胎盘及小肠中MT-1和MT-2mRNA表达的影响。方法:18只SD孕鼠随机分为正常对照组(ZC)和补锌组(ZS)。两组进食常规饲料,ZC组(n=9)饮用去离子水,ZS组(n=9)饮用补锌水(含1.26mmol/L锌)。分别于孕9.5d和孕17.5d时,取血、胎盘和母鼠小肠。以原子吸收分光光度法测定血清锌浓度;以半定量逆转录聚合酶链反应(RT-PCR)测定胎盘及小肠中MT-1和MT-2mRNA的表达。结果:孕9.5d和孕17.5d时,ZS组血清锌浓度均显著高于对照组。胎盘组织中MT-1和MT-2mRNA的表达均呈现出发育性改变趋势;ZS组各时间点MT-1和MT-2mRNA的表达均显著高于ZC组。ZS组母鼠小肠中,在孕9.5d时,ZS组和ZC组MT-1mRNA的表达无差异;孕17.5d时补锌组MT-1及各时间点MT-2的mRNA表达均显著增高。结论:膳食补充锌上调胎盘及母体小肠组织中MT-1和MT-2mRNA的表达。

Objective： To investigate the effect of zinc supplementation on expression of MT-1 and MT-2 mRNA in placenta and small intestine of pregnant rats. Method： Eighteen healthy pregnant SD rats were randomly divided into two groups, normal control （ZC） and zinc supplement group （ZS）. Rats in both groups were fed the same normal diet. Rats in ZC group drank deionized water and those in ZS group drank the water supplemented with 1.26 mmol/L Zn. At gestational 9.5d and 17.5d, serum zinc was determined by atomic absorption spectrophotometer and the expression of MT-1 and MT-2 mRNA of placenta and small intestine was examined by RT-PCR. Results： Serum zinc levels at gestational 9.5d and 17.5d were higher in ZS group. Relative expression of both MT-1 and MT-2 mRNA in placenta, MT-1 mRNA at gestational 17.5d and MT-2 mRNA at each time point were higher in ZS group. At gestational 9.5d, there was no difference between two groups in expression of MT-1 mRNA. Conclusion： The expression of MT-1 and MT-2 mRNA in placenta and small intestine was up-regulated by dietary zinc supplementation during pregnancy.