[Changes in glomerular polyanions and ultrastructure induced by protamine in rats]

Area of Science:

• Nephrology
• Pathology
• Molecular Biology

Background:

• Minimal change nephrotic syndrome (MCNS) is a leading cause of nephrotic syndrome in children.
• The exact pathomechanism of glomerular injury in MCNS remains incompletely understood.
• Polycations are known to interact with negatively charged components of the glomerular filtration barrier.

Purpose of the Study:

• To investigate the effects of polycation protamine perfusion on rat kidney glomeruli.
• To elucidate the role of glomerular polyanions in protamine-induced glomerular alterations.
• To compare experimental findings with pathological features of human MCNS.

Main Methods:

• Rat kidneys were perfused with protamine.
• Quantitative analysis of kidney tissue sections using image analysis and stereology.
• Assessment of glomerular ultrastructure, including foot process thickness and volume fraction.
• Colloidal iron staining to detect polyanions.

Main Results:

• Protamine perfusion induced glomerular alterations similar to human MCNS.
• Significant decrease in glomerular polyanions observed in protamine-perfused kidneys (P < 0.01).
• Observed swelling and fusion of foot processes, narrowing/loss of filtration slits, and electron-dense particle deposition.

Conclusions:

• Protamine perfusion serves as a valuable experimental model for studying MCNS.
• Neutralization of glomerular polyanions by protamine is implicated in the observed ultrastructural damage.
• These findings highlight the critical role of polyanions in maintaining glomerular filtration barrier integrity.