Scanning electron microscopy of cellular and acellular glomeruli of male dogs affected with Samoyed hereditary glomerulopathy and a carrier female.

Glomeruli isolated from three male dogs affected with Samoyed hereditary glomerulopathy were compared by scanning electron microscopy with glomeruli of one carrier female and six unaffected dogs. Scanning electron microscopy was performed before and after removal of podocytes and endothelial cells with enzyme and detergent, producing cellular and acellular glomeruli respectively. Cellular glomeruli of unaffected dogs showed podocytes with normally arranged foot processes, while in acellular glomeruli, the subepithelial surface of glomerular capillary basement membranes appeared smooth to finely granular. In contrast, cellular glomeruli of affected males showed microvilli, globular cytoplasmic projections from podocytes, and effacement of foot processes; acellular glomeruli demonstrated ridges and plaque-like irregularities on the subepithelial surface of glomerular capillary basement membranes. Changes in the glomeruli of the carrier female were intermediate between those of unaffected and affected male dogs. The appearance of the subepithelial surface of glomerular capillary basement membranes of acellular glomeruli seen by scanning electron microscopy correlated with the extent of multilaminar splitting of glomerular capillary basement membranes seen by transmission electron microscopy.