Morphological damage in the obstructed kidney (OK, 2B, D, F) compared to the contralateral kidney (CL, 2 A, C, E).

<p>All OK kidneys show tubular dilatation, flattened tubular epithelium with loss of brush border and reactive nuclear enlargement. Only Mmp2+/+ OK (2B) shows necrotic tubules (asterix) and many apoptotic cells (arrows). The morphology of the CL kidney is normal. (PAS stain).</p

Representative images of Picrosirius Red stained sections under polarised light from the obstructed kidney (OK, 3 B, D, F) compared to the contralateral kidney (CL, 3 A, C, E).

<p>There is a higher level of collagen in Mmp2+/+ OK (3 B) compared to OK in both Mmp2+/- and Mmp2-/- (3 D, F). Only minimal levels of collagen are detected in CL kidneys across all groups (3 A, C, E).</p

Image analysis of collagen in Picrosirius Red stained sections under polarised light.

<p>Collagen content is expressed as the percent of positive pixels to all pixels. * denotes P<0.05 compared to the contralateral kidney (CL). # denotes P<0.05 compared to OK in Mmp2+/+.</p

Representative images of Period Acid-Schiff (PAS) stained transversal sections showing increased morphological damage in the Mmp2+/+ obstructed kidney (OK, 1B) compared to the other groups (1 D, F).

<p>The Mmp2+/+ OK (1B) shows severe hydronephrosis and inflammation of the renal pelvis, while the Mmp2-/- OK (1F) and Mmp2+/- OK (1D) only display slight dilatation and minimal inflammation. The contralateral kidneys (CL, 1 A, C, E) do not differ from each other and show normal morphology.</p