Fig 2: Acetate, propionate, or butyrate regulated the expression of oxalate transporters SLC26A3 and SLC26A6 in the gut of rats receiving antibiotics. (A to D) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (A and B) and protein (C and D) level in the ileum of rats in antibiotics (Abx), ethylene glycol (EG), Abx + EG, Abx + EG + Acetate, Abx + EG + Propionate, and Abx + EG + Butyrate groups. (E to H) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (E and F) and protein (G and H) level in the cecum. (I to L) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (I and J) and protein (K and L) level in colon. At mRNA level, five rats of each group were examined, and the duplication was set as 3. At protein level, three rats of each group were examined. The relative protein expression of control group was set as 1. Student’s t test was applied. P > 0.05 (n.s.), P < 0.05 (*), P < 0.01 (**), P < 0.001 (***).

Fig 3: The decrease of intestinal SLC26A6 expression increased renal crystals, while the increase of intestinal SLC26A3 expression decreased renal crystals. (A) Hematoxylin and eosin (HE, ×100) and Von Kossa (VK, ×100) staining of renal tissues of rats in control, ethylene glycol (EG), A6, A6+EG, A6+EG+Acetate, A6+EG+Propionate, A6+EG+Butyrate, A3, A3+EG, A3+EG+Acetate, A3+EG+Propionate, and A3+EG+Butyrate groups. Blue arrows show calcium oxalate crystals. (B and C) The HE staining score (B) and VK staining value (C) in 12 groups. Three sections of each VK staining were captured for calculating area value. (D) The level of oxalate in urine. n = 5 rats/group. Student’s t test was applied. P > 0.05 (n.s.), P < 0.05 (*), P < 0.01 (**), P < 0.001 (***).

Fig 4: SCFAs regulated the expression of oxalate transporters SLC26A3 and SLC26A6 in the gut. (A to D) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (A and B) and protein (C and D) level in the ileum of rats in control, ethylene glycol (EG), EG + Acetate, EG + Propionate, and EG + Butyrate groups. (E to H) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (E and F) and protein (G and H) level in the cecum. (I to L) The expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (I and J) and protein (K and L) level in the colon. At mRNA level, five rats of each group were examined, and the duplication was set as 3. At protein level, three rats of each group were examined. The relative protein expression of the control group was set as 1. Student’s t test was applied. P > 0.05 (not significant [n.s.]), P < 0.05 (*), P < 0.01 (**), P < 0.001 (***).

Fig 5: Propionate and butyrate decreased oxalate transporter SLC26A3 expression, while acetate and propionate increased oxalate transporter SLC26A3 expression in human epithelial cell line Caco-2. (A to D) The effect of oxalic acid and/or acetate on the expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (A and B) and protein (C and D) level. (E to H) The effect of oxalic acid and/or propionate on the expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (E and F) and protein (G and H) level. (I to L) The effect of oxalic acid and/or butyrate on the expression of oxalate transporters SLC26A3 and SLC26A6 at mRNA (I and J) and protein (K and L) level. The relative protein expression of the control group was set as 1. Each experiment was repeated three times. The duplication was set as 3 at mRNA level. Student’s t test was applied. P > 0.05 (n.s.), P < 0.05 (*), P < 0.01 (**), P < 0.001 (***).