Luteolin alleviates methionine-choline deficient diet-induced non-alcoholic steatohepatitis by modulating host serum metabolome and gut microbiome

Background and purpose: Previous studies have indicated the therapeutic effects of luteolin against non-alcoholic steatohepatitis (NASH), but the definite underlying mechanism still remains unclear. The current study aimed to explore the metabolomic and metagenomic signatures of NASH with luteolin intervention.Experimental approach: Mice were fed with a methionine-choline deficient (MCD) diet containing 0.05% luteolin for 6 weeks. NASH severity was determined based on liver histological observations, serum and hepatic biochemical measurements. Targeted metabolomics was conducted to identify differential metabolites in mice serum. 16S rRNA sequencing was conducted to assess the gut microbiota composition and function in mice colon.Results: In detail, luteolin treatment significantly alleviated MCD diet-induced hepatic lipid deposition, liver function damage, and oxidative stress. Targeted plasma metabolomics revealed that 5-hydroxyindole, LPE (0:0/22:5), indole 3-phosphate and N-phenylacetylphenylalanine were remarkably elevated and homogentisic acid, thiamine, KN-93, PC (16:1e/8, 9-EpETE), carnitine C9:1-OH, FFA (18:4) and carnitine C8:1 were significantly decreased in NASH group as compared with normal group, which could be profoundly reversed after luteolin treatment. 16S rRNA sequencing indicated that luteolin supplementation significantly increased Erysipelatoclostridium and Pseudomonas as well as decreased Faecalibaculum at genus level. Most importantly, a negative association between thiamine and Faecalibaculum was observed based on spearman correlation analysis, which may play an important role in the therapeutic effects of luteolin against NASH.Conclusion: Collectively, luteolin may alleviate the non-alcoholic steatohepatitis by modulating serum metabolome and gut microbiome, which supports its use as a dietary supplement for NASH therapy.

研究背景与目的：既往研究表明木犀草素（luteolin）对非酒精性脂肪性肝炎（non-alcoholic steatohepatitis, NASH）具有治疗活性，但其确切的潜在作用机制仍未明确。本研究旨在探究木犀草素干预下非酒精性脂肪性肝炎的代谢组与宏基因组特征。
实验方法：将小鼠喂食含0.05%木犀草素的蛋氨酸-胆碱缺乏（methionine-choline deficient, MCD）饲料，持续6周。通过肝脏组织学观察、血清及肝脏生化指标检测评估非酒精性脂肪性肝炎的严重程度。采用靶向代谢组学技术鉴定小鼠血清中的差异代谢物；通过16S rRNA测序分析小鼠结肠内的肠道菌群组成与功能。
实验结果：具体而言，木犀草素处理可显著缓解MCD饲料诱导的肝脏脂质沉积、肝功能损伤及氧化应激。靶向血浆代谢组学分析显示，与正常对照组相比，NASH模型组小鼠血清中5-羟基吲哚、LPE(0:0/22:5)、吲哚-3-磷酸及N-苯乙酰苯丙氨酸水平显著升高，而尿黑酸、硫胺素、KN-93、PC(16:1e/8,9-EpETE)、肉碱C9:1-OH、FFA(18:4)及肉碱C8:1水平显著降低；上述代谢物的异常表达可经木犀草素干预得到显著逆转。16S rRNA测序结果表明，在菌群属水平上，木犀草素给药可显著提升红芽孢杆菌属（Erysipelatoclostridium）与假单胞菌属（Pseudomonas）的丰度，同时降低粪杆菌属（Faecalibaculum）的丰度。尤为关键的是，经斯皮尔曼相关性分析发现，硫胺素水平与粪杆菌属（Faecalibaculum）丰度呈显著负相关，这一关联可能在木犀草素抗NASH的治疗效应中发挥重要作用。
研究结论：综上，木犀草素可通过调节血清代谢组与肠道微生物组缓解非酒精性脂肪性肝炎，这为其作为NASH治疗的膳食补充剂提供了理论依据。