FIGURE 2:

Podocyte IRE1α deletion causes glomerular volume expansion and distended capillary loops, as well as collagen deposition, at 9 mo of age. (A) PAS stain. IRE1α^{flox/flox;Cre} (M Cre) mice have enlarged glomeruli, as well as enlarged glomerular capillary lumens, compared with control (IRE1α^flox/flox;+; M +). (B) There is increased capillary wall and mesangial collagen deposition in M Cre mice (Jones’ silver stain). (C) PAS-stained glomerular area is increased in M Cre mice (*p = 3.1 × 10⁻⁵). Mean of 48 M + glomeruli from three mice and 56 M Cre glomeruli from three mice. (D) Percentage of a given PAS-stained glomerulus that is occupied by capillary lumen is expanded in M Cre mice (*p = 0.0066). Average of 48 M + glomeruli from three mice, and 55 M Cre glomeruli from three mice. (E) Silver-stained glomeruli of M Cre mice have a higher fraction of glomerular tissue occupied by collagen than M + mice (*p = 1.45 × 10⁻⁵). Because the expanded capillary lumens in M Cre mice could confound this analysis, the capillary luminal area was subtracted from total glomerular cross-sectional area, so that the area of stained tissue could then be normalized to the total cross-sectional area of glomerular tissue. Imaging and quantification included 75 M + glomeruli from three mice and 74 M Cre glomeruli from three mice.