苦味西葫芦提高缺氧耐受性及其相关机制

Hypoxia tolerance and its underlying mechanisms in Cucurbita pepo cv Dayangua

摘要:

目的 明确苦味西葫芦(Cucurbita pepo cv Dayangua, CPD)对机体缺氧的改善能力，并探究其可能通过调节肠道菌群及代谢产物发挥作用的潜在机制。方法 将雄性昆明小鼠随机分为2组：对照组(normoxia ddH₂O, ND)、CPD干预组(normoxia CPD, CPD)。CPD干预组剂量为800 mg/(kg·d)，对照组给予相同体积的ddH₂O，连续给药15 d于最后一次给药1 h后将各组小鼠置于广口瓶内，观察并记录小鼠在广口瓶中的生存时间。在最后一次给药前收集小鼠粪便，进行16S rRNA基因扩增子测序和靶向代谢组检测，并开展肠道微生物和代谢物的关联性分析。结果 与对照组相比，CPD干预后显著延长了小鼠在缺氧条件下的存活时间。CPD干预可改变小鼠肠道菌群结构组成。线性判别分析效应大小(linear discriminant analysis effect size, LEfSe)分析发现，ND组与CPD组之间存在显著差异的细菌类群：CPD组中芽孢杆菌门(Bacillota)、乳杆菌属(Lactobacillus)、别样杆菌属(Alistipes)等微生物的相对丰度较高。与小鼠生存时间呈正相关的菌属有副普雷沃氏菌属(Paraprevotella)、乳杆菌属(Lactobacillus)等。靶向代谢组学表明CPD干预后有9种代谢物上调，31种代谢物下调，其中代谢物棕榈油酸(palmitoleic acid)、乙醛酸(glyoxylic acid)、十一烷酸(hendecanoic acid)、l-天冬氨酸(l-aspartic acid)、O-琥珀酰高丝氨酸(O-succinyhomoserine)、尿囊酸(allantoic acid)在CPD干预后显著富集，并且与小鼠生存时间呈显著正相关。通过差异代谢物KEGG富集分析，色氨酸代谢通路和甘氨酸、丝氨酸和苏氨酸代谢通路的富集程度最高。结论 CPD干预可显著延长缺氧小鼠的存活时间。CPD干预富集了包括乳杆菌属在内的有益微生物，并提升了胆碱(choline)、尿囊酸等有益代谢物的水平。这些发现提示调节“肠道微生物-代谢物”轴可能是CPD增强机体缺氧耐受性的机制之一，为开发针对缺氧相关疾病的微生态干预策略提供了理论依据和潜在靶点。

Abstract:

Objective To determine the efficacy of Cucurbita pepo cv Dayangua (CPD) in alleviating hypoxia and explore the potential mechanisms involving the modulation of the gut microbiota and its metabolites.Methods Male Kunming mice were randomly assigned into two groups: a control group (normoxia ddH₂O, ND) and a CPD intervention group (normoxia CPD, CPD). The CPD group received a dose of 800 mg/(kg·d) of CPD, while the ND group received an equal volume of ddH₂O for 15 consecutive days. One hour after the final administration, mice from each group were placed in wide-mouth bottles, and the survival time was observed and recorded. Fecal samples collected prior to the last administration were subjected to 16S rRNA gene amplicon sequencing and targeted metabolomics analysis. Correlation analysis between gut microbiota and metabolites was subsequently performed.Results CPD intervention significantly prolonged the survival time of mice under hypoxic conditions compared to the ND group. CPD altered the structural composition of the gut microbiota in mice. Linear discriminant analysis effect size (LEfSe) revealed significantly different bacterial taxa between the ND group and the CPD group, with higher relative abundance of Bacillota, Lactobacillus, and Alistipes in the CPD group. Microbial genera, including Paraprevotella and Lactobacillus, showed a positive correlation with survival time. Targeted metabolomics identified 9 upregulated and 31 downregulated metabolites in the CPD group. Notably, metabolites such as palmitoleic acid, glyoxylic acid, hendecanoic acid, l-aspartic acid, O-succinylhomoserine, and allantoic acid were significantly enriched and positively correlated with the survival time of mice after CPD intervention. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis of differential metabolites showed the highest enrichment in the tryptophan metabolism and glycine, serine, and threonine metabolism pathways.Conclusion CPD intervention significantly prolonged the survival time of hypoxic mice. CPD intervention enriched beneficial microorganisms, including Lactobacillus, and elevated the levels of beneficial metabolites such as choline and allantoic acid. These findings suggest that modulating the “gut microbiota-metabolite” axis may be one mechanism through which CPD enhances host hypoxia tolerance, providing a theoretical basis and potential targets for developing microecological intervention strategies against hypoxia-related diseases.