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廣東藥科大學郭姣、蘇政權教授團隊在Food & Function發表題目為“Ameliorating the effect and mechanism of chitosan oligosaccharide on nonalcoholic fatty liver disease in mice”研究論文（殼寡糖對小鼠非酒精性脂肪肝的改善作用及機制）。 此前的研究發現，殼寡糖（COST）可以緩解非酒精性脂肪肝（NAFLD）患者的臨床癥狀。 我們打算用不同濃度的COST對高脂肪飲食誘發的NAFLD小鼠進行干預。 通過生理生化指標觀察COST對NAFLD模型小鼠的基本作用。 采用16S rRNA測序技術分析腸道微生物群，進一步分析短鏈脂肪酸（SCFA）含量。采用Western blot和RT-PCR檢測COST對NAFLD小鼠肝臟PI3K/AKT/mTOR信號通路的影響。 結果發現，COST高劑量組可減輕NAFLD小鼠體重，改善血脂異常，減輕肝臟病變，且COST對NAFLD小鼠有治療作用。 16S rRNA 測序分析表明，COST 可以增加 NAFLD 小鼠腸道微生物群的多樣性。NAFLD 小鼠中 SCFA 的下調被逆轉。 WB和RT-PCR結果顯示PI3K/AKT/mTOR信號通路參與NAFLD小鼠的發生發展。 COST 通過抑制肝臟 DNL 改善 NAFLD 小鼠的肝臟脂質代謝。COST可增加產熱蛋白、UCP1和PGC-1α基因的表達；PI3K/AKT/mTOR信號通路在蛋白質和基因水平上受到抑制。本研究揭示，COST通過腸道微生物群和SCFAs調節脂質毒性引起的相關炎癥因子的表達，改善HFD誘導的NAFLD小鼠的肝臟脂質代謝，為開發有效、低毒的治療NAFLD藥物奠定了基礎。 3.1 COST可改善NAFLD小鼠的癥狀
Fig. 1 Average weekly food intake (a) and weight gain (b) in NAFLD mice. COST affected insulin (c) and fasting blood glucose levels (d), area under glucose curve (e) and serum glucose curve of the oral glucose tolerance test (f). COST affected serum levels of FFA (g), TG (h), TC (h), LDL-C (h) and HDL-C (h) in each group. COST affected serum levels of TNF-α, IL-1β, IL-6 and IL-10 in each group (i). Influence of COST on the serum antioxidant function indices CAT and T-AOC of mice in each group (j). At the end of the experiment, serum LPS histogram of mice in each group and HE staining of ileal and colon sections of mice (k) (200×, scale 50 μ.). (n = 6, mean ± SEM. Note: Compared with model group, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.) 3.2.COST可改善NAFLD小鼠的肝損傷，調節肝臟脂質代謝紊亂
Fig. 2 COST affected the changes of serum liver function indices AST and ALT in each group (a) (n = 6, mean ± SEM). Direct morphology and pathological section of livers of mice in each group after COST administration (b) (n = 6, 200×, scale 50 μ. mean ± SEM). COST affected the levels of TG, TC, HDL-C and LDL-C in the livers of mice in each group (c) (n = 6, mean ± SEM). Effect of COST on the expression of SREBP-1c, ACC, FAS and SCD-1 proteins in livers of mice in the NAFLD group (d) (n = 3, mean ± SEM). Effect of COST on the relative expression levels of TNF-α, IL-6, IL-1β and IL-10 genes in the livers of mice in the NAFLD group (e) (n = 6, mean ± SEM). (Note: compared with the model group, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.) 3.3.COST可改變NAFLD患者的脂肪比例，促進褐色脂肪脂質氧化，提高脂質代謝水平
Fig. 3 COST affected the adipose tissue proportion, brown adipose tissue coefficient, epididymal white adipose tissue coefficient, perirenal white adipose tissue coefficient and subcutaneous white adipose tissue coefficient in each group (a) (n = 6, mean ± SEM). H&E staining of brown adipose tissue (b), epididymal white adipose tissue (c), perirenal white adipose tissue (d), and subcutaneous white adipose tissue (e) after COST treatment. (200×, scale 50 μ.) (n = 6, mean ± SEM). Effect of COST on UCP1 and PGC-1α (f–h) protein levels (n = 3, mean ± SEM) and gene level expression (i and j) in the brown fat of mice in the NAFLD group (n = 6, mean ± SEM). (Note: Compared with the model group, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.) 3.4.COST給藥可改變NAFLD小鼠腸道微生物群的組成，并提高腸道微生物群多樣性
Fig. 4 Venn diagram of the OTU sequence of each group after the experiment (a). Analysis diagram of the α diversity index of each group after the experiment, dilution curve (b), observed species index (c), ACE index (c), Chao1 index (c), Shannon index (c), and Simpson index (c). Analysis of β diversity in each group after the experiment (d). The relative abundance of the top 10 species at phylum (e), species (f) and genus (g) levels, the relative abundance graph of Akkermansia, Ligilactobacillus and Desulfovibrio predominant flora (h), and the ratio of Firmicutes to Bacteroidetes (i). (n = 6, mean ± SEM. Note: Compared with the model group, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.)3.5.COST給藥可以增加優勢細菌的豐度，并可能逆轉NAFLD小鼠SCFA降解的趨勢 
Fig. 5 Histogram of the LDA effect values of each group (a) and taxonomic branch diagram (b) of each group after the experiment. Short-chain fatty acids in each group after the experiment (c). (n = 6, mean ± SEM. Note: compared with the model group, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.) 3.6.COST干預可抑制PI3K/AKT/mTOR信號通路，提高NAFLD肝臟的脂質代謝水平
Fig. 6 Effect of COST on PI3K/Akt/mTOR signaling pathway protein expression in NAFLD mice (a) (n = 3, mean ± SEM). Effect of COST on PI3K/Akt/mTOR mRNA expression in NAFLD mice (b) (n = 6, mean ± SEM). (Note: compared with the model group, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.)DOI https:///10.1039/D3FO03745B
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