Effects of fibrinolytic treatment on rabbit Masugi nephritis

We investigated the effects of administration of urokinase (UK) and trans-4-aminomethylcyclohexane carboxylic acid (t-AMCHA) on the development of experimental rabbit Masugi nephritis. Treatment with 1000 U/kg of UK, 5000 U/kg of UK and 100 mg/kg of t-AMCHA twice a day intravenously was initiated on the 7th and continued for 7 consecutive days. Concomitantly with the nephrotoxin injection, 5000 U/kg of UK was also given twice a day intravenously for 14 days. The administration of 5000 U/kg of UK twice a day for 7 days and 14 days suppressed the increases in BUN values and the decreases in urinary fibrinolytic activity. Fibrin-fibrinogen degradation products (FDP) were detected more frequently in the urine of rabbits given UK than in the control. Immunofluorescence microscopy showed a decrease in intra- and extra-glomerular fibrin deposition, and a decrease in fibrin or fibrinoid deposits in Bowman's space by 5000 U/kg of UK was demonstrated electron microscopically. Light microscopy revealed that the accumulation of fibrin in glomeruli, crescent formation, and progressive glomerular disorganization by 5000 U/kg of UK were prevented. On the other hand, treatment with t-AMCHA enhanced the increase in BUN values and there was a decrease in urinary fibrinolytic activity. Dense fibrin deposits in the glomeruli, were observed immunopathologically by treatment with t-AMCHA and histopathologic changes were found to be even more severe.