Histopathological Assessment of Kidney Fibrosis

Paraffin embedded kidneys sections (2 μm) were stained with Masson’s Trichrome and Periodic Acid Schiff (PAS). Assessment of glomerulosclerosis and tubulointerstitial fibrosis was done by two examiners independently. Twenty non-overlapping fields were captured under an Olympus photo light microscope linked to a Leica DFC 480 digital camera. A semiquantitative glomerulosclerosis index (GSI) score was graded on a scale of zero to four (0_normal; 1_involvement of <25% of the glomerulus, 2_ involvement of 25–50% of the glomerulus; 3_involvement of 50–75% of the glomerulus and 4_totally sclerosed glomeruli)^{41 (link)}. The whole kidney average GSI score was obtained by averaging scores from all counted glomeruli in one section. For tubulointerstitial scoring ten non-overlapping fields were assessed in a similar grading system to the GS score as previously described^{42 (link)}. Paraffin sections of liver, lung and heart from control and control animals treated for 24 weeks with the LOXL2 inhibitor were stained with haematoxylin and eosin (HE) and evaluated for structural damage by an independent pathologist.