肥胖对小鼠肝脏GDF-15、TMPRSS6、Hepcidin表达的影响

Effect of obesity on GDF-15,TMPRSS6 and Hepcidin expression in mouse liver

目的观察肥胖小鼠肝组织中铁代谢相关调控因子铁调素(hepcidin)mRNA,生长分化因子-15(GDF-15)和跨膜丝氨酸蛋白酶6(TMPRSS6)蛋白表达的变化,及血液和肝组织57Fe的相对含量及其意义。方法 4-6周雄性C57BL/6J小鼠20只被随机分为肥胖模型组和正常对照组,每组10只。肥胖模型组和对照组分别给予高脂饲料和普通饲料。饲喂至15周,肥胖模型建模成功。建模成功后,以0.1 ml/10 g的计量标准,对全部小鼠经口一次性灌注^(57)FeSO_4溶液。1 h后,取小鼠心脏血液及肝脏。免疫组化法检测肝脏中GDF-15、TMPRSS6的相对表达量,real-time PCR法检测肝脏hepcidin mRNA,ICP-MS法测定血液及肝脏中^(57)Fe的相对含量。结果与对照组相比,肥胖组小鼠肝脏中hepcidin表达增加(0.282±0.109 vs 0.494±0.139,P<0.01),GDF-15表达减少(0.097±0.005 vs 0.035±0.006,P<0.01),血液^(57)Fe表达减少[(22.970±4.492)μg/ml vs(15.647±1.629)μg/ml,P<0.05)],肝脏^(57)Fe表达减少[(603.103±35.511)μg/g vs(226.073±12.124)μg/mg,P<0.05],而TMPRSS6的表达尚不能认为差异有统计学意义(0.068±0.009 vs 0.085 3±0.027,P>0.05)。结论机体TMPRSS6表达量的变化不受肥胖因素影响。但肥胖可以下调机体GDF-15的表达,并由此升高肝脏hepcidin的表达,最终导致肝脏及血液铁含量减少。

Objective To observe the changes of the expression of hepcidin mRNA,growth differentiation factor-15（GDF-15） and transmembrane serine protease 6（TMPRSS6） protein in hepatic tissues of obese mice,as well as the relative contents of ^（57）Fe in blood and hepatic tissues,and explore its significance.Methods Twenty male C57 BL/6 J mice aged 4-6 weeks were randomly divided into obesity model group and normal control group,with 10 mice in each group.The mice were fed with high-fat diet in obesity model group and ordinary feed in normal control group.Until the fifteen week after high-fat diet,the obesity model was successfully established.Then,all mice were orally infused with ^（57）FeSO_4 solution at a dose of 0.1 ml/10 g.One hour after infusion,the blood in mouse heart and liver was collected.The relative content of ^（57）Fe in blood and liver were determined by ICP-MS,and the relative expression of GDF-15 and TMPRSS6 in the liver was detected by immunohistochemistry,and hepcidin mRNA was detected by real-time PCR.Results Compared with control group,the expression of hepcidin increased in the liver in obese group（0.282 ± 0.109 vs 0.494 ± 0.139,P 0.01）,while the expression of GDF-15 decreased（0.097 ± 0.005 vs 0.035 ± 0.006,P 〈0.01）.Compared with control group,the expression of ^（57）Fe decreased in blood[（22.970 ± 4.492） μg/ml vs（15.647 ± 1.629） μg/ml,P 〈0.05] and in liver [（603.103 ±35.511） μg/g vs（226.073 ± 12.124） μg/mg,P 〈0.05].but the expression of TMPRSS6 was not considered statistically significant（0.068 ± 0.009 vs 0.085 3 ± 0.027,P 〉0.05）.Conclusion TMPRSS6 expression may not be affected by obesity.However,obesity could increase hepcidin expression in the liver by down-regulating GDF-15 expression,and lead to a reduction of iron content in the liver and blood.