硫酸亚铁对缺铁性贫血小鼠肠道健康的影响

Effect of ferrous sulfate on intestinal health of mice with iron deficiency anemia

摘要:

【目的】旨在探究硫酸亚铁(FeSO₄)对缺铁性贫血(iron deficiency anemia, IDA)小鼠肠道健康的影响。【方法】选取45只24日龄体重(16.0±1.2) g的雄性昆明小鼠，随机分成3组，每组15只，即对照组(正常饲料，饮蒸馏水)、IDA组(低铁饲料造模2周，饮去离子水)、IDA-Fe²⁺组(造模结束后灌胃FeSO₄ 3周，饮去离子水)，实验结束时采样。【结果】试验结束时，与IDA组相比，IDA-Fe²⁺组小鼠的红细胞、血红蛋白、红细胞压积、平均红细胞体积、平均红细胞血红蛋白量、平均红细胞血红蛋白浓度等贫血指标均恢复至正常水平(P>0.05)，表明FeSO₄具有改善IDA的功能；与对照组相比，IDA和IDA-Fe²⁺组小鼠的氧化应激指标和肿瘤坏死因子α均显著升高(P<0.01)、紧密连接蛋白Occludin显著降低(P<0.001)，IDA-Fe²⁺组与IDA组除结肠总抗氧化能力(TAC)外均无差异显著性(P>0.05)。结肠组织HE染色结果表明：与对照组相比，IDA组小鼠的结肠组织黏膜层萎缩，黏膜层上皮细胞排列缺损，固有层萎缩。灌胃FeSO₄ 3周后，观察到IDA-Fe²⁺组小鼠黏膜层上皮细胞排列仍有缺损，黏膜层腺泡部分存在坏死与缺损，固有层萎缩。对粪便微生物群进行的Illumina MiSeq高通量测序结果表明，IDA会导致小鼠肠道菌群紊乱，菌群多样性指数显著改变(Shannon、Chao1、Ace和Simpson指数，P<0.05)；灌胃FeSO₄后，相较于IDA组，IDA-Fe²⁺组小鼠菌群多样性指数显著增加、肠道菌群的整体结构显著改善(P<0.05)；在门水平上，Bacteroidetes显著降低(P<0.05)，Verrucomicrobia显著升高(P<0.01)，均恢复至正常水平；在属水平上，改变了主要优势菌属的丰度，有益菌Akkermansia、Coprobacter丰度显著增加(P<0.05)，致病菌Parabacteroides丰度显著降低(P<0.01)。【结论】FeSO₄可以通过改善IDA小鼠的血液指标来缓解IDA症状，但对IDA小鼠的结肠氧化应激指标、炎症指标和结肠组织病变情况没有改善作用。补充FeSO₄可以增加IDA小鼠肠道菌群多样性和优势菌群丰度，使有益菌丰度增加，致病菌丰度降低。

关键词:缺铁性贫血;氧化应激;肠道菌群

Abstract:

[Objective] To explore the effect of ferrous sulfate (FeSO₄) on the intestinal health of iron deficiency anemia (IDA) mice. [Methods] A total of 45 24-day-old male Kunming mice with initial body weight of (16.0±1.2) g were randomized into 3 groups (15 in each): control group (normal diet, distilled water), IDA group (low-iron diet for 2 weeks for modeling, deionized water), and IDA-Fe²⁺ group (after modeling, gavage with FeSO₄ for 3 weeks, deionized water). Sampling performed at the end of the experiment. [Results] Anemia indexes of mice in IDA-Fe²⁺ group, such as erythrocyte, hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC), returned to normal levels compared with those in the IDA group (P>0.05), indicating that FeSO₄ can alleviate IDA. Compared with the control group, IDA and IDA-Fe²⁺ groups had high levels of oxidative stress indexes and tumor necrosis factor α (P<0.01) and low level of Occludin (P<0.001). The indexes, except for the total antioxidant capacity (TAC), were insignificantly different between the IDA-Fe²⁺ and IDA groups (P>0.05). As for the hematoxylin and eosin (HE) staining results of colon tissue, the IDA group showed atrophy of colonic mucosa, defective arrangement of epithelial cells in mucosa, and atrophy of lamina propria. After intragastric administration of FeSO₄ for 3 weeks, IDA-Fe²⁺ group still demontrated defective arrangement of epithelial cells in the mucosa, necrotic and defective acini of mucosa, and atrophy of lamina propria. According to the results of Illumina MiSeq high-throughput sequencing of fecal microbiota, IDA could lead to the disorder of intestinal microflora and the variation of diversity indexes (Shannon, Chao1, Ace, and Simpson indexes) of intestinal flora (P<0.05). IDA-Fe²⁺ group showed significant increase in diversity indexes of the flora and improvement of the overall structure of intestinal flora as compared with the IDA group (P<0.05). To be specific, at the phylum level, the abudance of Bacteroidetes decreased (P<0.05) and that of Verrucomicrobia increased (P<0.01), both returning to the normal levels. At the genus level, the abundance of the dominant genera changed. The abundance of the beneficial Akkermansia and Coprobacter increased (P<0.05) and that of the pathogenic Parabacteroides decreased (P<0.01). [Conclusion] FeSO₄ can alleviate IDA symptoms by improving the blood indexes, but failes to improve the oxidative stress indexes, inflammation indexes, and colon tissue pathological changes of IDA mice. However, FeSO₄ can increase the diversity of intestinal flora and the abundance of main dominant flora in IDA mice, raising the abundance of beneficial bacteria and reducing the abundance of pathogenic bacteria.

Key words:iron deficiency anemia (IDA);oxidative stress;gut microbiota