Fig. 1.

MSCs transplantation ameliorates fibrosis and renal tubulointerstitial injury in 2K1C rats. Picrosirius red-stained left kidney sections of renal cortex and medulla examined under non-polarized (A–F) and polarized (G–L) light microscopy from sham, 2K1C and 2K1C + MSCs groups. Sham kidneys preserve regular histoarchitecture, with minimal interstitial space (A, B) and display no collagen birefringence under polarized light evaluation (G, H). An intense collagen deposition in a widened interstitial space was detected both in the cortex and medulla of 2K1C clipped kidneys (C, D, I, J). 2K1C + MSCs group displayed a normal renal parenchyma, with no collagen birefringence detection (K, L). Black arrows indicate areas with collagen localization stained in red. White arrows and asterisks indicate orange-red and yellow-green birefringence, respectively. Scale bars = 15 μm; 2K1C = Two Kidney-One Clip; MSCs = Mesenchymal Stem Cells.