Effect of Hyperlipidemia on Nephropathy in Streptozotocin-Induced Diabetic Rats

Electron Microscopy

Abstract

The effect of hyperlipidemia induced by cholesterol (CHS)-feeding or Triton WR-1339 (Triton) injection on renal glomerular lesions in the streptozotocin (STZ)-induced diabetic rats was ultrastructurally studied. In non-diabetic and hyperlipidemic rats, mesangial cells contained electron-lucid vacuoles or droplets but showed no cellular proliferation or increase in type IV collagen and fibronectin positive areas. In STZ-diabetic rats, however, either with or without lipidemia mesangial cells were significantly increased in number, showing “mesangial interposition” between the capillary lamina densa and endothelial cells. The mesangial cells and the capillary basement membrane were positive for type IV collagen, and the former was also positive for fibronectin. Some mesangial cells were packed with a number of electron dense droplets or vacuolation, narrowing the capillary lumen. The basement membrane was thicker and type IV collagen- as well as fibronectin-positive areas were expanded in STZ-diabetic and hyperlipidemic rats.