2005 Volume 99 Issue 3 Pages 287-293
The aim of this study was to investigate the disposal of aggregated protein in the glomeruli of spontaneously diabetic mice. Diabetic mice, KK-Ay and db/db, and age-matched ICR mice were injected intravenously with aggregated bovine serum albumin (a-BSA) at 0.6 mg/g, and the glomeruli and the blood were obtained. Diabetic mice had larger amounts of a-BSA in their glomeruli than the ICR mice, threefold in KK-Ay and twofold in db/db, at 3 h after the a-BSA injection. Additionally, the disappearance of a-BSA was retarded in the diabetic glomeruli. KK-Ay displayed a-BSA in the glomeruli 24 h after the a-BSA injection and db/db did after 12 h, while the ICR did by 8 h. In spite of increases of insulin to similar degrees in both strains of diabetic mice after the a-BSA injection, blood glucose levels markedly decreased in KK-Ay compared with db/db. There were no histopathological alterations in the glomeruli of the diabetic mice. Depositions of a-BSA were confirmed to be higher in the diabetic glomeruli by the immunofluoresnce technique, and KK-Ay displayed higher depositions of a-BSA than did db/db. The present study suggests that hyperglycemia is involved in the increased deposition of aggregated protein in the glomeruli and that the degradation of aggregated protein is retarded in diabetic glomeruli.