Search

Objective: To explore the protective mechanism of Auricularia auricula melanin (AAM) on iron deficiency anemia (IDA) induced ulcerative colitis (UC) in mice. Methods: Forty-five Kunming male mice were randomly divided into blank control group, model group, and AAM group (n = 15 each). The mice from all groups except the blank control one were provided with a low-iron diet to establish an IDA-induced UC model. After two weeks, AAM was administered by gavage to the mice from the AAM group for three weeks, whereas those from the model group continued receiving the low-iron diet. The effects of AAM on anemia indexes, colonic inflammation characteristics, oxidative stress, inflammatory factor expression levels and inflammatory signaling pathways in UC mice were evaluated. Results: Compared with the model group, the symptoms of anemia in the AAM group were alleviated. The body mass returned to the normal level, and the colonic pathological score was significantly reduced (P < 0.000 1). In addition, the total antioxidant capacity (TAC) and superoxide dismutase (SOD) activity in the colon of mice from the AAM group were significantly enhanced compared with the model group (P < 0.000 1), and the levels of malondialdehyde (MDA), hydroxyl radical (·OH), and superoxide anion radical (O2-·) were significantly decreased (P < 0.000 1, P < 0.01, P < 0.001), indicating that AAM could enhance antioxidant capacity and attenuate oxidative damage in mice. Further mechanistic studies showed that intervention with AAM significantly regulated protein expression associated with Toll-like receptors-4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway, significantly down-regulated the gene expression of the pro-inflammatory cytokine tumor necrosis factor (TNF-α) (P < 0.01), and significantly increased the gene expression level of the anti-inflammatory cytokine interleukin-10 (IL-10) (P < 0.05). Conclusion: Auricularia auricula melanin may regulate oxidative stress and inhibit the TLR4/NF-κB signaling pathway, thereby reducing intestinal mucosal ulcer, oxidative stress injury and inflammatory cell infiltration in colon tissue, and finally alleviating IDA-induced UC in mice.

Iron deficiency anemia (IDA) is a common iron deficiency disease. IDA has become one of the major public health problems worldwide. Our previous studies have shown that Auricularia auricula melanin (AAM) can alleviate IDA, but the mechanism is not clear. In this study, the role of the intestinal microflora in the improvement of IDA by AAM was studied by elimination of gut bacteria using an antibiotic cocktail as well as using metabonomics. The results showed that AAM treatment significantly alleviated anemia symptoms of IDA mice in terms of body mass, hemoglobin concentration, hematocrit, mean erythrocyte volume and platelet count, and this effect was lost when the intestinal flora was eliminated. Totally 76 differential metabolites were identified by metabolnomics analysis. Pathway enrichment analysis identified seven pathways including tryptophan metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, ascorbic and uronic metabolism, glutathione metabolism, tyrosine metabolism, pentose and glucuronate interconversion and steroid hormone biosynthesis. Among these, tryptophan metabolism was most significant. In the presence of intestinal microflora, tryptophan metabolites such as 5-hydroxyindole acetic acid and N-formyl kynurenine were significantly accumulated in IDA mice supplemented with AAM, indicating that AAM could mitigate IDA, which may be related to activation of tryptophan metabolism through the intestinal flora. This study may provides a theoretical basis for further research on the mechanisms by which AAM improves IDA and for the development of anti-IDA products.

Objective: To explore the effect of Auricularia auricula melanin on the physiology and intestinal flora of mice with iron deficiency anemia (IDA). Methods: A total of 45 male Kunming mice aged 24 days were randomly divided into two groups: control (15 animals) and model (30 animals). The control group was given a normal diet and deionized water. The model group was given a low-iron diet and ultrapure water for two weeks to induce IDA, and then was randomly divided into two groups with 15 animals each: IDA and IDA-M. The IDA and IDA-M groups were given the low-iron diet and ultrapure water and gavaged with 0.2 mL of A. auricula melanin solution at a dose of 200 mg/(kg mb·d) and an equal volume of ultrapure water for another three weeks, respectively. The mice in all groups were weighed every week. At the end of the experiment, routine blood test was carried out and the composition of the intestinal flora in each group of mice were measured by high-throughput sequencing. Results: After two weeks of feeding, the body mass of mice in the model group decreased significantly compared with that of the mice in the control group (P < 0.05). After three weeks of intervention with melanin, compared with the IDA group, the body mass of the mice in the IDA-M group increased significantly (P < 0.05), and the anemia symptoms such as leukocyte count, erythrocyte count, hemoglobin concentration, hematocrit and mean corpuscular volume returned to the normal level, suggesting that A. auricula melanin alleviates IDA. IDA could cause intestinal flora disorder and significantly change the diversity indices of the intestinal flora (Shannon, Chao1, Ace and Simpson index) (P < 0.05). Compared with the IDA group, the diversity indies and the overall structure of the intestinal flora in the IDA-M group were significantly improved (P < 0.05). At the phylum level, the relative abundance of Bacteroidetes and Proteobacteria decreased significantly, the relative abundance of Firmicutes and Verrucomicrobia increased significantly, and all of them returned to the normal level. At the genus level, A. auricula melanin increased the relative abundance of the dominant bacteria, significantly increased the relative abundance of the beneficial bacteria Alistipes and Akkermansia (P < 0.05) and decreased the relative abundance of the pathogenic bacteria Parabacteroides and Bacteroides (P < 0.05). Conclusion: A. auricula melanin can alleviate the symptoms of IDA in mice by increasing body mass and improving routine blood indices, and it can also increase the diversity of the intestinal flora and the relative abundance of the dominant microflora and beneficial bacteria, and decrease the relative abundance of pathogenic bacteria.

Bioactive glass (BG) has been widely used in bone tissue engineering due to its good osteogenic property and bioactivity, but it still has some deficiencies, such as poor cell adhesion and low osteogenic rate and so on. Mesoporous biological glass (MBG) is a kind of new material originated from BG and mesoporous silica (MS). Because of its large number of nano-channel, large specific surface area, easy degradation, good biocompatibility and biological activity, MBG has great application prospects in the field of bone tissue engineering. This review would present MBG preparation and experimental research in order to provide the theoretical basis and experimental reference for related researches.

Arbuscular mycorrhizal (AM) fungi play an important role in energy flow and nutrient cycling, besides their wide distribution in the cosystem. With a long co-evolution, AM fungi and host plant have formed a symbiotic relationship, and fungal lipid metabolism may be the key point to find the symbiotic mechanism in arbusculart mycorrhiza. Here, we reviewed the most recent progress on the interaction between AM fungal lipid metabolism and symbiotic signaling networks, especially the response of AM fungal lipid metabolism to symbiotic signals. Furthermore, we discussed the response of AM fungal lipid storage and release to symbiotic or non-symbiotic status, and the correlation between fungal lipid metabolism and nutrient transfer in mycorrhiza. In addition, we explored the feedback of the lipolysis process to molecular signals during the establishment of symbiosis, and the corresponding material conversion and energy metabolism besides the crosstalk of fungal lipid metabolism and signaling networks. This review will help understand symbiotic mechanism of arbuscular mycorrhiza fungi and further application in ecosystem.