Fig. 4. Glomerular abnormalities in adult endothelium-specific Pdgfb knockouts. H/E staining of 3-week-old kidneys revealed an increased glomerulus diameter (A,B) and capillary loop diameter (C) in lox/– mice compared with controls. Capillary diameters of the lox/– animals differ significantly from those of the control group (P<0.005). The relative distribution of the maximal capillary diameter in the control and endothelium-specific Pdgfb knockout groups is shown. Measured diameters have been corrected to the closest 1 µm to yield an illustrative figure. PAS staining of adult kidneys did not reveal signs of pathology at the age of 6 months (D,F) or >1 year (E,G). Glomerular cell count and matrix volume were comparable in the various genotypes, Scale bar: 10 µm). (H,I) Urine albumin levels were increased in lox/– mice that were more than a year old (P<0.05), but not in 6-month-old lox/– mice (P>0.05). Glomerular PDGFB protein levels (J,K) were reduced in lox/– mice and the reduction was significant (P<0.005) in mice that were more than a year old. Bars represent levels (±s.d.) of albumin secretion (H,I) and PDGFB protein (J,K).