Podocytic degeneration and regeneration in puromycin aminonucleoside nephropathy in the rat

In various types of chronic glomerulonephritis, proliferation of mesangial and endothelial cells is often seen together with extracellular matrix accumulation. In contrast, the proliferation of visceral glomerular epithelial cells (podocytes) has not been detected in any disease in which these cells are the principal target of injury. To examine whether proliferation of podocytes occurs, puromycin aminonucleoside nephropathy was induced in Wistar rats by intraperitoneal injection of puromycin aminonucleoside (15 mg/100 g of bodyweight). In this nephropathy model of nephrotic syndrome with minimal change, the main lesions consisted of vacuolation and flattened foot processes of podocytes, which are the primary target of puromycin aminonucleoside. Urine protein excretion and proliferating cell nuclear antigen (PCNA) positive cells were examined. The PCNA+ podocytic count reached its maximum on day 3, indicating that the most marked podocytic proliferation occurs just after the injection of PAN. Twenty-four hour urinary excretion in this nephropathy model supported the hypothesis that mitosis of podocytes occurs in association with recovery on day 13.