大鼠心脏二价金属转运体1表达量的不同发育期变化及其调节

Developmental expression and regulation of divalent metal transporter 1 in rat heart

目的 :研究二价金属转运体 1(divalent metal transporter 1,DMT1)在大鼠心脏中的表达及其受膳食铁调节的情况。方法 :采用 RT- PCR和 Western blot技术 ,观察 DMT1在雄性 Sprague- Dawley大鼠心脏中的表达。结果 :两种亚型的 DMT1m RNA(non- IRE形式和 IRE形式 )在不同年龄 (7、2 1、6 3和 196 d)的大鼠心脏中均有表达 ,随着大鼠年龄的增加 ,DMT1m RNA的表达量增加 ,并且其表达量与心脏中的铁含量呈正相关。出生 2 1d的大鼠用高铁或低铁饲料喂养 6周后 ,分别造成心脏铁超载和铁缺乏模型。高铁组、低铁组与对照组相比 ,心脏 DMT1m RNA的表达量没有明显变化 ;Western blot分析结果显示 ,DMT1蛋白 (non- IRE形式和 IRE形式 )在铁缺乏的心脏中含量分别增加 2 1%和 4 0 % (P<0 .0 1) ,在铁超载的心脏中其含量降低 2 6 %～ 2 8% (P<0 .0 1)。结论 :DMT1在心脏中的表达受膳食铁和心脏铁含量的调节 ,其调节方式与转铁蛋白受体不同 ,是一种转录后调节。

Objective: To investigate the expression of divalent metal transporter 1 (DMT1) mRNA in male Sprague Dawley rat heart of different ages and the expression of DMT1 regulated by dietary iron. Methods: Reverse transcriptase (RT) PCR and Western blot were used in this study. Results: (1)Two isoforms of DMT1 mRNA [with and without iron responsive element (IRE)] were both detected in rat heart, which were correlated with heart iron content. During development, both of two isoforms of DMT1 mRNA expression were the lowest at the age of PND 7, and increased at PND 21, 63 to 196. (2)After fed with a high iron diet or low iron diet for 6 weeks, the rats developed iron overload or iron deficiency respectively. No significant differences in DMT1 mRNA expression were detected among iron overload, iron deficienct and control rats. By using Western blot analysis, a 21% and 40% reduction in DMT1 protein non IRE form and IRE form respectively were found in iron overload rat ( P <0.01, vs control). Increases (26%~28%) in the levels of two isoforms of DMT1 protein were also observed in iron deficient rat ( P <0.01, vs control). Conclusion: The level of DMT1 mRNA expression in heart is age dependent; the two isoforms of DMT1 protein may be both regulated by iron on the posttranscriptional mechanism.[