Microangiographic evaluation of the effects of heparin on progressive Masugi nephritis.

Unilateral progressive Masugi nephritis was produced in rabbits and studied by microangiography as well as light and immunofluorescence microscopy. The following five groups were studied: Group 1. Heparin was started simultaneously with nephrotoxic serum (NTS) and was given for one week. The animals were then sacrificed along with the untreated controls. Group 2. This was the same protocol as in group 1 but with three weeks' heparin. Group 3. Heparin was started one day after NTS was given for three weeks. Group 4. Heparin was started one to two weeks after NTS and was given for three weeks. Group 5: late effect group. Heparin was started simultaneously with NTS, was given for four weeks, and the animals were then sacrificed 10 to 13 weeks later. Heparin dose was 5,000 U, s.c., per day in all treated groups. The number of glomeruli seen per unit of cortex by microangiography was significantly increased in the first through the third groups, as compared to the controls. Group 1 did not show this increase but there was some decrease of immunofluorescent fibrinogen. The late effect group (group 5) showed no modification by the treatment, suggesting that an initial improvement may have been negated by persistent immunologic insults after heparin withdrawal.