Fig. 3: Long-term statins administration worsens renal fibrosis in db/db mice.

All mice were ~50 weeks old. a Representative Masson’s trichrome staining. In the picture, collagenous components are stained as blue color and cytoplasm is varying shades of red. Collagen deposits (blue) are evident within the fibrotic interstitial lesions between tubular, and even in the glomerulus, as marked by arrows. Original magnification ×200. Scale bar: 100 µm. b Representative images of Sirius red staining for tubulointerstitial fibrosis. Sirius red staining showed fibrosis (Red color) in kidney fibrotic interstitial lesions, as marked by arrows. Original magnification ×200. Scale bar: 100 µm. c Immunohistochemistry of COL1A1 staining. COL1A1 is mainly expressed on the extracellular matrix (ECM), and the specific location is indicated by the arrows⁵⁰. Original magnification ×400 or ×1000. Scale bar: 100 or 20 µm. d Immunohistochemistry of α-SMA staining. α-SMA is used as a marker for a subset of activated fibrogenic cells, myofibroblasts, which are regarded as important effector cells of tissue fibrogenesis. Arrows represent numerous activated fibrogenic cells in tubulointerstitium and glomeruli⁵⁰. Original magnification ×400 or ×1000. Scale bar: 100 or 20 µm. e Quantification of tubulointerstitial fibrosis in the kidney cortex. f, g Quantification of immunohistochemical staining. All image part of the kidney was cortex. Renal structures indicated as glomerulus (G), proximal tubule (PT), and distal tubule (DT), extracellular matrix (ECM). Data are expressed as means ± SEM. n = 6 in each group. One-way ANOVA with Tukey post hoc test was used for the analysis of statistical significance. Source data are provided as a Source Data file.