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背景:小肠锌吸收降低会导致皮炎、脱发、生长发育障碍等。低锌状态下如何保持小肠锌内稳态的作用途径至今尚不清楚,锌转运体的发现及相关研究为其提供了新的研究方向。目的:观察低锌浓度对二价金属离子转运体1和锌铁调控蛋白4mRNA表达的影响,分析低锌状态下小肠锌吸收的可能途径。设计:空白对照观察。单位:解放军第二军医大学海医系军队卫生学教研室。材料:实验于2004-10/2005-05在解放军第二军医大学军队卫生学教研室完成,人结肠腺癌细胞系Caco2购自上海中科院细胞所。方法:将Caco2细胞培养至一定浓度。①时间效应:应用反转录聚合酶链反应分别检测10μmol/LTPEN暴露时,0,2,4,6,8和10h时相点Caco2细胞二价金属离子转运体1和锌铁调控蛋白4mRNA的表达情况。②剂量效应:应用反转录聚合酶链反应分别检测0,2.5,5,7.5,10μmol/LTPEN暴露时,各组Caco2细胞二价金属离子转运体1和锌铁调控蛋白4mRNA的表达情况。主要观察指标:锌对Caco2细胞二价金属离子转运体1和锌铁调控蛋白4mRNA表达影响的时间和剂量效应。结果:①时间效应:与0h比较,2h和4h时二价金属离子转运体1mRNA表达水平没有明显变化,6h,8h和10h,二价金属离子转运体1mRNA均有显著升高(P<0.05)。锌铁调控蛋白4mRNA表达水平随着时间的延长而升高,6h达到峰值,为0h的2.1倍。②剂量效应:二价金属离子转运体1mRNA的表达量在TPEN浓度为2.5和5μmol/L时没有明显改变,7.5和10μmol/L时二价金属离子转运体1mRNA的表达量较对照组有显著升高(P<0.05)。锌铁调控蛋白4mRNA的表达量随着TPEN浓度的升高而升高,10μmol/L时锌铁调控蛋白4mRNA表达量为0μmol/L时的2.7倍。结论:Caco2细胞二价金属离子转运体1和锌铁调控蛋白4mRNA表达受锌的调控,并且有时间和剂量效应,但是锌铁调控蛋白4mRNA变化较二价金属离子转运体1mRNA变化敏感且迅速。低锌状态下,细胞可能通过上调二价金属离子转运体1和锌铁调控蛋白4mRNA表达水平而调节细胞锌内稳态。
Background: Reduced intestinal zinc absorption can lead to dermatitis, hair loss, growth and development disorders. How to maintain the zinc homeostasis in the low zinc state is still unclear. The discovery and related research of zinc transporter provide a new research direction. OBJECTIVE: To observe the effect of low zinc concentration on the expression of bivalent metal ion transporter 1 and zinc-iron regulatory protein 4 mRNA, and to analyze the possible pathways of zinc absorption in the small intestine under low zinc status. Design: Blank control observation. Unit: PLA Second Military Medical University Department of Marine Medicine Department of Hygienics. MATERIALS: The experiment was performed at the Department of Military Hygiene, Second Military Medical University, PLA from October 2004 to May 2005. The human colon adenocarcinoma cell line Caco2 was purchased from Shanghai Chinese Academy of Sciences. Methods: Caco2 cells were cultured to a certain concentration. ① Time effect: Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of divalent metal ion transporter 1 and zinc-regulated protein 4 mRNA in Caco2 cells at 0, 2, 4, 6, 8 and 10 h after exposure to 10 μmol / Express the situation. ② The dose-effect: The mRNA expression of divalent metal ion transporter 1 and zinc-iron regulatory protein 4 in Caco2 cells of each group were detected by reverse transcription polymerase chain reaction (RT-PCR) at 0,2.5,5,7.5,10μmol / LTPEN exposure. MAIN OUTCOME MEASURES: Time and dose effects of zinc on the expression of divalent metal ion transporter 1 and zinc-iron regulatory protein 4 mRNA in Caco2 cells. RESULTS: ① Time effect: Compared with 0h, there was no significant change in mRNA expression of bivalent metal ion transporter at 2h and 4h, and mRNA expression of bivalent metal ion transporter increased significantly at 6h, 8h and 10h (P <0.05) . Zinc and iron regulatory protein 4 mRNA expression levels increased with time, peaked at 6h, 2.1 times of 0h. ② The dose effect: The expression level of bivalent metal ion transporter 1 mRNA did not change when the concentration of TPEN was 2.5 and 5μmol / L, and the expression of bivalent metal ion transporter 1 mRNA was significantly increased compared with the control group at 7.5 and 10μmol / L High (P <0.05). The expression of Zinc-regulated protein 4 mRNA increased with the increase of TPEN concentration, and was 2.7-fold at 10μmol / L when the expression of Zinc-iron regulatory protein 4 mRNA was 0μmol / L. CONCLUSION: The expressions of divalent metal ion transporter 1 and zinc-iron regulatory protein 4 mRNA in Caco2 cells are regulated by zinc and have time and dose effects. However, the changes of zinc-iron regulatory protein 4 mRNA are more sensitive and rapid than that of divalent metal ions transporter 1 mRNA. In the low zinc state, the cells may regulate the zinc homeostasis by up-regulating the expression levels of divalent metal ion transporter 1 and zinc-regulated protein 4 mRNA.