The pathophysiological processes linked to kidney disease. The pathophysiological processes linked to kidney disease. (A) A normal, healthy kidney (left), and a magnified view of the structure of a tubule and its associated vasculature (right). (B) A chronically diseased kidney, showing the processes that lead to tubulointerstitial fibrosis. (C,D) Histological sections of an adult rat kidney, stained with Masson's trichrome (20× magnification; scale bars: 50 µm). (C) The glomerular and tubular architecture of a normal adult rat kidney, and (D) glomerulosclerosis (#) and tubulointerstitial fibrosis (*) in a 12-month-old hydroxysteroid dehydrogenase 2 (Hsd11b2)-knockout rat exhibiting end-stage renal disease. Linda J. Mullins et al. Dis. Model. Mech. 2016;9:1419-1433 © 2016. Published by The Company of Biologists Ltd