Studies of Nephrotoxic Nephritis. II. The Fine Structure of the Glomerulus in Acute Nephrotoxic Nephritis of Dogs

Abstract

The fine structural changes of the glomerulus in nephrotoxic nephritis are described. The early change (phase I) is a "quellung" and occasionally longitudinal splitting of the basement membrane. From approximately the seventh day on (phase II), there is proliferation of intracapillary cells (endothelial and axial), and deposition of an electron-dense material between endothelium and basement membrane, and between the proliferated intracapillary cells. These are thought to be antigen-antibody complexes. In the second phase, intracapillary cells increase in size and number, and contain numerous cytoplasmic organelles. There is also an increase in the number of mitochondria and of rough-surfaced vesicles in the epithelial cells. These cells manifest, also, vacuolation, formation of hyaline (protein absorption) droplets, and fusion of foot processes. The first phase results from an interaction between the nephrotoxic antibody and basement membrane. The second phase is more complex. The various possible mechanisms that operate during the second phase are enumerated and discussed.