Kidney - Glomerulonephritis

Glomerulonephritis (GN) results from acute to chronic glomerular injury resulting in glomeruli that appear enlarged and hypercellular with an increase in mesangial matrix (Figure 1, Figure 2, and Figure 3). Primary GN is not commonly observed in routine rodent studies. There are morphologic subtypes of GN, which have certain histologic features that may indicate an underlying pathogenesis. These morphologic subtypes are often classified as proliferative, membranoproliferative, mesangioproliferative, or crescentic. Proliferative GN appears hypercellular without further identification of increased cells or basement membrane thickening. Membranoproliferative GN is characterized by basement membrane thickening, either uniform or irregular, which can be demonstrated by periodic acid-Schiff or silver stains. Mesangioproliferative GN is characterized by an increase in the number of mesangial cells. In crescentic GN, segmental areas of visceral or parietal cells form adhesions to one another and reduce Bowman’s space. In addition, modifiers such as "diffuse" and "segmental" can also be applied to further characterize the change within glomeruli.