Gut microbiota depletion attenuates systemic and tubulointerstitial inflammation in diabetic rats. Gut microbiota of DM rats was depleted by treatment with broad-spectrum antibiotics administered in the drinking water (DM+AB). (A) Serum inflammatory cytokines, including IL-1β, TNF-α, MCP-1 and IL-6, were measured by ELISA (n=4). (B) Tubulointerstitial inflammation was detected by immunohistochemical staining (scale bar, 500 μm and 100 μm, original magnification × 200). (C-D) Expression levels of inflammatory proteins in renal cortex were detected by Western blot analysis and quantified (n=4-5). (E-F) Histopathological injuries of tubulointerstitium were evaluated by PAS staining (scale bar, 500 μm and 100 μm, original magnification × 200) and quantified (n=5). *P < 0.05; **P < 0.01; ***P < 0.001.