Fig. 4: Colonization of B. ovatus accelerate metformin-induced VB12 deficiency in HFD-induced mice.

a Introduction of B. ovatus strain in microbiota-depleted mice (n = 5 mice/group). b, c Fold changes of relative abundance of B. ovatus in colon contents and small intestine contents of mouse recipients based on q-PCR analysis, respectively (n = 5). d The concentrations of plasma VB12 (n = 5). e The concentrations of plasma methylmalonic acid (MMA) (n = 5). f The concentrations of plasma homocysteine (Hcy) (n = 5). g The relative levels of plasma folate (n = 5). h Hepatic TG levels (n = 5). i Oil Red O staining on liver tissues; scale bars, 50 μm (n = 3). j H&E staining of subcutaneous fat (sWAT); scale bars, 100 μm (n = 3). k Adiponectin immunohistologic staining of sWAT sections; scale bars, 50 μm (n = 3). l Representative gross the peri-gonadal fat images from HFD and B.ovatus-colonized type 2 diabetes mice treated with vehicle or metformin for 4 weeks. m Sections of mouse pancreas were analyzed by immunofluorescence using antibodies to Insulin (red) and glucagon (green); scale bars, 100 μm (n = 3). P value determined by the Mann–Whitney U test (b, c, h), one-way ANOVA with Tukey’s or Dunnett’s tests (d, e, g) and Kruskal–Wallis test (f). All data are presented as mean ± SEM or mean ± SD.