The effects of polyvinyl alcohol on the uptake and processing of colloidal carbon by the glomerular mesangium in rats

Inbred Lewis rats given polyvinyl alcohol (PVA) in 28 daily subcutaneous doses of 50 mg. per 100 gm., served as kidney donors to normal Lewis recipients. Rats receiving renal transplants from normal donors served as controls. Four days later the transplant recipients received colloidal carbon, 70 mg. per 100 gm., intravenously. Where PVA was deposited as finely dispersed droplets within the glomerular mesangium (GM) there was no difference in the uptake and processing of the colloidal carbon by the GM on comparing these GM areas with the GM of the recipients' own contralateral kidney at 3 days and 3 and 8 weeks following carbon administration. Increased localization of carbon was noted in GM areas containing moderately large PVA aggregates. Electron microscopy revealed that persistence of carbon in these GM areas was associated with entrapment of carbon in the PVA aggregates and disruption of the GM intercellular channel system. Very large masses of PVA in the GM were associated with total distortion of the glomerular tuft architecture and decreased carbon uptake. Transplantation per se had no influence on GM carbon uptake or processing. This model allows study of GM function where the GM structure is disturbed in a kidney sharing an identical environment with a normal kidney. Furthermore, it suggests that abnormalities of GM function are directly related to the severity of GM architectural abnormalities.