基于肠道菌群和广泛靶向代谢组学的山柰酚抗骨质疏松的作用机制

Anti-osteoporotic mechanisms of kaempferol based on gut microbiota and comprehensive targeted metabolomics

背景:山柰酚具有抗骨质疏松的作用,但山柰酚通过调控肠道菌群、代谢物防治骨质疏松的作用机制尚不明确。目的:基于肠道菌群和广泛靶向代谢组学探究山柰酚抗骨质疏松的可能作用机制。方法:将雌性Sprague-Dawley大鼠18只随机分为假手术组、模型组和山柰酚组,每组6只,后2组切除双侧卵巢制备骨质疏松大鼠模型。造模后8周,假手术组和模型组采用蒸馏水灌胃,山柰酚组采用40 mg/kg山柰酚灌胃,各组均连续给药12周。取大鼠粪便进行16SrDNA扩增子测序,观察肠道菌群结构的变化;采用超高效液相色谱-串联质谱技术、自主开发的数据库和多元统计分析的方法进行血清样本广泛靶向代谢组学检测。结果与结论:①连续干预12周后,16SrDNA扩增子测序结果显示,与假手术组相比,模型组肠道菌群丰度增加;与模型组相比,山柰酚组上调Latilactobacillus菌属(P=0.021)丰度,下调泛菌属(Pantoea)(P=0.034)、肠杆菌属(Enterorhabdus)(P=0.000)、Monoglobus菌属(P=0.024)、丁酸单胞菌属(Butyricimonas)(P=0.034)、Rothi属(P=0.043)、梭杆菌属(Clostridia)(P=0.004)等菌属丰度。②连续干预12周后,血清样本广泛靶向代谢组学检测结果显示,假手术组与模型组、模型组与山柰酚组之间分别鉴定出120和79种代谢物,3组间共有17种交集差异代谢物,包括乌头酸、巴比妥酸、L-高瓜氨酸、3,4,5-三甲氧基肉桂酸、L-3-苯基乳酸、环(脯氨酸-脯氨酸)、L-苯丙氨酸-L-丝氨酸、脯氨酸-异亮氨酸、L-冬胺基乙酸-L-苯丙胺基乙酸、苯丙氨酸-天冬氨酸等。大部分属于氨基酸及其代谢物、甘油磷脂类和脂肪酰类。差异代谢物涉及的KEGG通路主要富集在D-氨基酸代谢、组氨酸代谢、丙酸代谢、赖氨酸降解、脂肪酸代谢、鞘脂代谢等。③连续干预12周后,联合分析发现,肠杆菌属(Enterorhabdus)、Latilactobacillus属、Rothia属和瘤胃球菌属(Ruminococcus)等与血清差异代谢物密切相关。④山柰酚可能通过调节肠道菌群的丰度、多样性及结构,调控氨基酸及其代谢物的代谢、脂肪酸代谢等发挥抗骨质疏松的作用。

BACKGROUND:Kaempferol has anti-osteoporotic effects,but the mechanisms by which kaempferol regulates gut microbiota and metabolites to prevent and treat osteoporosis remain unclear.OBJECTIVE:To exploring the potential mechanisms by which kaempferol inhibit osteoporosis based on gut microbiota and comprehensive targeted metabolomics.METHODS:Eighteen female Sprague-Dawley rats were randomly divided into three groups:sham operation group,model group,and kaempferol group,with 6 rats in each group.Animal models of osteoporosis were made in the latter two groups through removal of bilateral ovaries.Eight weeks after modeling,the sham operation and model groups were gavaged with distilled water,and the kaempferol group was gavaged with 40 mg/kg kaempferol.Continuous administration in each group was carried out for 12 weeks.Rat fecal samples were collected for 16S rDNA amplicon sequencing to observe changes in the gut microbiota structure.Serum samples were subjected to comprehensive targeted metabolomics analysis using ultra-high performance liquid chromatography-tandem mass spectrometry technology,along with a proprietary database and multivariate statistical analysis.RESULTS AND CONCLUSION:After 12 weeks of continuous intervention,the results of 16S rDNA amplicon sequencing showed that compared with the sham operation group,the abundance of gut microbiota increased in the model group.Compared with the model group,kaempferol group exhibited a statistically significant increase in the abundance of the genus Latilactobacillus(P=0.021),while the abundances of Pantoea(P=0.034),Enterorhabdus(P=0.000),Monoglobus(P=0.024),Butyricimonas(P=0.034),Rothia(P=0.043),and Clostridia(P=0.004)were significantly downregulated.After 12 weeks of continuous intervention,the results of the serum samples analyzed by broad-targeted metabolomics revealed that 120 and 79 metabolites were identified between the sham operation and model groups and between the model and kaempferol groups,respectively.Among the three groups,there were 17 overlapping differentially expressed metabolites,including Cis-aconitic acid,barbituric acid,L-homocitrulline,3,4,5-trimethoxycinnamic acid,L-3-phenyllactic acid,cyclo(pro-pro),L-phenylalanine-L-serine,proline-isoleucine,L-donoraminoacetic acid-L-phenylalanineacetic acid,and phenylalanine-aspartic acid.Most of them belong to amino acids and their metabolites,glycerophospholipids and fatty acyls.The Kyoto Encyclopedia of Genes and Genomes pathways involved in the differential metabolites were mainly enriched in D-amino acid metabolism,histidine metabolism,propionate metabolism,lysine degradation,fatty acid metabolism and sphingolipid metabolism.After 12 weeks of continuous intervention,combined analysis revealed that genera such as Enterorhabdus,Latilactobacillus,Rothia,and Ruminococcus were closely associated with differential serum metabolites.To conclude,kaempferol may exert its anti-osteoporotic effects by modulating the abundance,diversity,and structure of gut microbiota,thereby regulating the metabolism of amino acids,their metabolites,and fatty acids.