豌豆超微粉碎膳食纤维对糖尿病小鼠肠道菌群及其代谢产物的影响

Effects of Ultrafine Ground Pea Dietary Fiber on Intestinal Flora and Metabolites in Diabetic Mice

目的:研究豌豆超微粉碎膳食纤维(ultrafine ground pea dietary fiber,UGPDF)对糖尿病小鼠肠道菌群及其代谢产物的影响,从而揭示其降血糖的作用机制。方法:通过腹腔注射链脲佐菌素建立糖尿病小鼠模型,用二甲双胍和高剂量(0.9 g/(mL·d))、低剂量(0.45 g/(mL·d))UGPDF分别灌胃干预4周,测定小鼠血糖浓度、观察肝脏细胞形态变化,Western blot检测小鼠肝脏中磷脂酰肌醇-3-激酶(phosphatidylinositol-3-kinase,PI3K)/蛋白激酶B(protein kinase B,AKT)/类胰岛素生长因子(insulin-like growth factors,IGF)蛋白表达水平,高通量测序分析各组小鼠粪便中的肠道菌群组成。结果:UGPDF能够调节糖尿病小鼠的肠道菌群丰度及多样性,高剂量UGPDF组操作分类单元(operational taxonomic units,OTU)数达300±36,其Shannon、Simpson指数与糖尿病小鼠存在显著差异(P<0.05)。在肠道菌群组成中,与模型组相比,UGPDF干预后,Lactobacillus、Lachnospiraceae有益菌相对丰度显著上升(P<0.05),Helicobacter、Klebsiella、Clostridium致病菌相对丰度显著下降(P<0.05)。从代谢产物来看,与模型组相比,经过UGPDF干预后,小鼠粪便内的6种短链脂肪酸含量总体显著升高(P<0.05),其中以高剂量组效果最为显著,乙酸、丙酸、丁酸含量分别提高了63.7%、75.9%和96.0%,且接近正常对照组。同时,肝脏组织切片及Western blot检测结果表明UGPDF可调节糖尿病小鼠肝脏PI3K/AKT/IGF信号通路,修复肝细胞损伤,提高胰岛素敏感性。本实验可为豌豆膳食纤维的高值化利用拓宽思路,并补充完善其降血糖理论。

The aim of this study is to clarify the effects of ultrafine ground pea dietary fiber(UGPDF)on the intestinal microflora and metabolites of diabetic mice so as to reveal the mechanism of its hypoglycemic effect.A diabetic mouse model was established by intritoneal injection of streptozotocin,and the diabetic mice were gavaged with either metformin or UGPDF with high-dose(0.9 g/(mL·d))and low-dose(0.45 g/(mL·d))for four weeks.The changes in blood glucose level and liver cell morphology were measured during the experimental period.The protein expression levels of phosphatidylinositol-3-kinase(PI3K),protein kinase B(AKT)and insulin-like growth factors(IGF)were detected by Western blot.The composition of the fecal microbial flora of mice in each group was analyzed by high-throughput sequencing.The results showed that UGPDF could regulate the abundance and diversity of the intestinal microflora in diabetic mice.The number of operational taxonomic units(OTUs)in the high-dose UGPDF group was 300±36,and the Shannon and Simpson indexes of this group were significantly different from those of diabetic mice.UGPDF intervention increased the abundance of beneficial bacteria such as Lactobacillus and Lachnospiraceae(P<0.05),and decreased the abundance of pathogenic bacteria such as Helicobater,Klebsiella compared to the model group(P<0.05).Moreover,after UGPDF intervention,the contents of six short-chain fatty acids in the feces of mice were significantly increased,and the most significant effect was observed in the high-dose group,showing an increase in the contents of acetic acid,propionic acid and butyric acid by 63.7%,75.9%and 96.0%,respectively,reaching a level similar to that of the normal group.At the same time,the results of liver Histological examination and Western blot showed that UGPDF could regulate the PI3K/AKT/IGF signaling pathway in the liver of diabetic mice,repair liver cell injury and improve insulin sensitivity.