(山西农业大学食品科学与工程学院 山西太谷 030801)
(College of Food Science and Engineering， Shanxi Agricultural University， Taigu 030801， Shanxi)
目的:基于胰岛素-铁代谢交互作用探讨膳食脂肪酸构成对肝脏糖水平的影响。方法:21日龄清洁级雄性SD大鼠60只，随机分为:对照组、15%大豆油组(15% SO)、15%猪油组(15% PO)、15%橄榄油组(15% OO)、15%鱼油组(15% FO)及1∶1 SO∶FO组。首先以气相色谱法测定油脂脂肪酸构成，之后以不同油脂干预大鼠13周，测定其肝脏葡萄糖、胰岛素含量，检测血红蛋白、血清铁、铁蛋白以及肝脏中的铁含量，以普鲁士蓝染色观测肝脏组织铁沉积情况，以实时荧光定量聚合酶链式反应(qRT-PCR)检测大鼠肝脏组织铁代谢关键基因的表达量。结果:SO中n-6不饱和脂肪酸含量为46.37%，FO中n-3不饱和脂肪酸含量为37.55%，PO中饱和脂肪酸含量为24.78%，OO中单不饱和脂肪酸含量为36.39%。各组大鼠肝脏中葡萄糖含量无明显差异，而1∶1 SO∶FO组大鼠肝脏胰岛素水平显著低于对照组及15% SO组(P＜0.05)。各组大鼠血红蛋白及铁蛋白含量无显著性差异，而15% SO组血清铁含量最高且显著高于对照组及1∶1 SO∶FO组(P＜0.05)。与对照组相比，15% PO组肝脏铁含量显著性升高(P＜0.05)。普鲁士蓝染色结果显示，15% SO组和15% PO组棕褐色颗粒增多。铁代谢相关基因检测结果表明，与对照组相比，15% SO组和15% PO组铁调素(Hep)基因表达显著降低(P＜0.05)；15% SO组和15% PO组膜铁转运蛋白(Fpn1)基因的表达量显著性低于其它各高脂组(P＜0.05)。与对照组相比，15% FO组二价金属转运蛋白1(DMT-1)基因的表达量显著性升高(P＜0.05)，15% PO组转铁蛋白受体2(TfR2)基因的表达量显著性降低(P＜0.05)。结论:相较于15% SO，15% 1∶1 SO∶FO可以抑制机体血清铁水平增高及肝脏铁的沉积，进而抵御胰岛素敏感性的降低；15% OO及15% FO对肝脏铁沉积无明显影响，而15% PO则可以引起肝脏的铁沉积，提示适量的补充鱼油对于肝脏糖、铁代谢具有一定的改善作用。
Objective: In this study， the effects of different dietary fatty acid composition on liver glucose level were discussed based on the interaction of insulin and iron metabolism. Methods: Sixty 21-day-old clean male SD rats were randomly divided into: control group， 15% SO group， 15% PO group (lard)， 15% OO group (olive oil)， 15% FO group (fish oil)， and 1∶1 SO∶FO group. Firstly， the fatty acid compositions of oils were determined by gas chromatography， and then the contents of glucose and insulin in liver were measured after 13 weeks of intervention with different oils. The contents of hemoglobin， serum iron， ferritin in liver were also detected， and the iron deposition in liver tissue was observed by prussian blue staining. The key genes expressions of iron metabolism in rat liver was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Results: The n-6 unsaturated fat acid content in SO was 46.37%， the n-3 unsaturated fat acid content in FO was 37.55%， the saturated fat acid content in PO was 24.78%， and the monounsaturated fatty acid content in OO was 36.39%. There were no significant differences in the contents of glucose in the liver of rats in each group. The level of hepatic insulin in the rats of 1∶1 SO∶FO group was significantly lower than that in the control group and the 15% SO group (P < 0.05). There were no significant differences in hemoglobin and ferritin among all the groups， but the serum iron content in 15% SO group was the highest and significantly higher than that in the control group and 1∶1 SO∶FO group (P < 0.05). Compared with the control group， the iron content in liver of 15% PO group was significantly higher (P < 0.05)， and prussian blue staining results showed that brown particles increased in 15% SO group and 15% PO group. The expression of hepcidin (Hep) gene decreased significantly in 15% SO group and 15% PO group (P < 0.05)； the expression of ferroportin 1 (FPN 1) gene in 15% SO group and 15% PO group was significantly lower than those in other high-fat groups (P < 0.05). Compared with the control group， the expression of divalent metal transporter 1 (DMT-1) gene in 15% FO group was significantly higher (P < 0.05). Compared with the control group， the expression of transferrin receptor-2 (TfR-2) gene in 15% PO group decreased significantly (P < 0.05). Conclusion: Compared with 15% SO， 15% 1∶1 SO∶FO could inhibit the increase of serum iron level and liver iron deposition， and then resist the decrease of insulin sensitivity； 15% OO and 15% FO had no remarkable effect on liver iron deposition， while 15% PO could cause liver iron deposition. Overall， appropriate supplementation of fish oil can improve liver glucose and iron metabolism.