Dendrobium officinale polysaccharide
(DOP), the main active component, has a variety of bioactivities.
In this study, a type 2 diabetes mellitus (T2DM) and antibiotic-induced
pseudo-germ-free mouse models were used to investigate the hypoglycemic
mechanisms of DOP. The findings showed that DOP ameliorated dysfunctional
glucolipid metabolism, lipopolysaccharide (LPS) leakage, and metabolic
inflammation levels in T2DM mice. Furthermore, DOP significantly upregulated
the mRNA expression of tight junction proteins Claudin-1, Occludin, and ZO-1 and reduced
intestinal inflammation and oxidative stress damage through the LPS/TLR4/TRIF/NF-κB
axis to repair the intestinal barrier. Interestingly, pseudo-germ-free
mouse experiments confirmed that the above beneficial effects of DOP
were dependent on gut microbiota. 16S rRNA analysis showed that DOP
strongly inhibited the harmful bacterium Helicobacter by 94.57% and facilitated the proliferation of probiotics Allobaculum, Bifidobacterium, and Lactobacillus by 34.96, 139.41,
and 88.95%, respectively. Therefore, DOP is capable of rebuilding
certain specific intestinal microbiota to restore intestinal barrier
injury, which supports the utilization of DOP as a new type of prebiotic
in functional foods for T2DM.