Fig. 3. Glomerular abnormalities in endothelium-specific Pdgfb knockouts. Hematoxylin/Erythrosin (H/E) staining (A-F) and -smooth muscle actin immunostaining (G-J) of E18.5 kidney glomeruli of different genotypes. Normal glomeruli containing a mesangial cell core (outlined by arrowheads, G) were seen in wild-type (A) and control (C,E,G) kidneys, whereas the Pdgfb^–/– (B) and some of the lox/– (D,J) glomeruli completely lacked mesangial cells. In these cases, the glomerular capillary tufts become replaced by single dilated capillary loops. Most lox/– glomeruli show a reduced mesangial core (outlined by arrowheads, H), leading to a reduction in tuft complexity and dilation of the remaining capillary loops (F,H). (K) Morphometric analysis of glomerular capillary dilation; the relative distribution of capillary diameters in glomeruli of the same genotype is shown. The capillary diameters of the lox/– animals differ significantly from those of all other groups (P<0.005). Note that the range of values, but not their distribution, is similar for lox/– and –/– (k/o). There is no difference between controls (sum of flox/+, flox/–, lox/+) and wild type (P>0.05). Measured diameters have been corrected to the closest 5 µm to yield an illustrative figure. Scale bar: 10 µm.