Fig. 5.

Alleviation of VDN-induced vascular calcification in rats by the propionate-modulated intestinal microbiota. a A flow diagram of the faecal microbiota transplantation experiment. Rats in the control and VDN + SP groups were raised for 28 days. Following this, faecal samples were collected from these donors on a daily basis. Based on procedures described in the methodology section, a bacterial solution was prepared and then transplanted continually into the recipient rats for 14 days. The recipients were separately assigned to the control→VDN and VDN + SP→VDN groups. b Macroscopic observation of arterial vascular calcification through alizarin red staining. c Quantitative assessment of calcium content in macroscopic blood vessels. d Observation of vascular calcification of the ascending aorta by alizarin red staining of tissue sections (original magnification ×40). e Relative quantification of calcium content for the sections of ascending aortas. f–h Concentrations of the proinflammatory cytokines TNF-α, IL-1β and IL-6 in plasma, respectively. VDN: Vitamin D3 and nicotine; FMT: faecal microbiota transplantation. Data are presented as the mean ± standard deviation (SD). Statistical significance was determined using one-way ANOVA (Tukey post hoc test). #P < 0.25, ##P < 0.1, *P< 0.05, **P< 0.01, ***P< 0.001, ****P< 0.0001