Influence of zinc on expression of zinc transporter mRNA in Caco2 cells / 中国组织工程研究

ABSTRACT

BACKGROUND: Decreasing of absorption of zinc from small intestine can induce dermatitis, alopecia, growth and developmental disorder and so on. It is not very clear that how to keep homeostasis when there is low zinc concentration. The discoveries of zinc transporters and relative researches provide new study direction.OBJECTIVE: To study the effect of different zinc concentration on the expressions of divalent metal transporter 1 (DMT1) and human zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP) 4mRNA, and analyze the potential pathway of absorption of zinc from small intestine in low zinc concentration.DESIGN: Blank-controlled experiment.SETTING: Department of Military Hygiene, Navy Faculty, Second Military Medical University of Chinese PLA.MATERIALS The experiment was accomplished in Department of Military Hygiene, Navy Faculty of Second Military Medical University of Chinese PLA between October 2004 and May 2005. Materials were human colon adenocarcinoma cells Caco2 that were purchased from Shanghai Institute of Cell of Chinese Academy of Sciences.Time-dependent effect The expression of DMT1 and ZIP4 mRNA was detected with reverse transcription-polymerase chain reaction (RT-PCR) at 0,dependent effect The expression of DMT1 and ZIP4 mRNA were measured after the 0, 2.5, 5, 7.5 and 10 μmol/L TPEN exposure, respectively, by RT-PCR.MAIN OUTCOME MEASURES: Time-and dose-dependent effect of zinc on the expression of DMT1 and ZIP4 mRNA in Caco2 cells.RESULTS: ①Time-dependent effect Compared with 0 hour, the expression of DMT1 mRNA obviously increased at 6, 8 and 10 hours (P ＜ 0.05 ), but there was no significant change at 2 and 4 hours. The expression of ZIP4 mRNA markedly increased in all timing, and ZIP4 mRNA level at the 6th hour reached the peak with the prolongation of low zinc duration,which was 2.1 times ofthat at 0 hour. ②Dose-dependent effect The expression of DMT1 mRNA distinctly increased at the concentration of 7.5 and 10 μmol/L TPEN exposure as compared with that of the control group (P ＜ 0.05), but there was no significant change at 2.5 and 5 μmol/L. The ZIP4 mRNA expression increased with the increasing of the concentration of TPEN, the expression of ZIP4 mRNA was 2.7 times of that at 0 μmol/L. CONCLUSION: Zinc can regulate the expression of DMT1 and ZIP4 mRNA in Caco2 cells, and there is time-and dose-dependent effect. But the mRNA expression of ZIP4 is more sensitive and prompt than DMT1. Cells can upregulate the expression of DMT1 and ZIP4 mRNA to keep the homeostasis in low zinc condition.