The acute effect of passive Heymann nephritis on renal blood flow and glomerular filtration rate in rats.

The acute renal hemodynamic changes during induction of passive Heymann nephritis (PHN) may be of importance for the understanding of the pathogenesis of this model. We studied the renal blood flow (RBF) and glomerular filtration rate (GFR) during and after infusion of anti-FxlA into the left renal artery of rats for 10 min. 3 control groups were given 0.9% NaCl, 1 and 2 mg of normal rabbit IgG, respectively. The experimental groups were given 1 and 2 mg IgG fraction of anti-FxlA. Compared to controls, both RBF and GFR were substantially reduced during the first 20-30 min after infusion and remained unaltered for the rest of the observation period. After 20-30 min, RBF in the 1-mg group was 4.8 +/- 0.77 ml/min/g kidney weight versus control, 6.4 +/- 1.23 (NS), and in the 2-mg group, 3.5 +/- 0.65 ml/min/g versus control, 6.4 +/- 1.07 (p less than 0.05). Similarly, in the 1-mg group, GFR was 0.40 +/- 0.08 ml/min/g versus control, 0.76 +/- 0.11 (p less than 0.05), and in the 2-mg group, 0.14 +/- 0.05 versus control, 0.77 +/- 0.12 (p less than 0.0001). The reductions were greater in the 2-mg than in the 1-mg infused experimental groups, but this difference did not reach statistical significance. Immunofluorescence showed typical granular fluorescence of rabbit IgG along the glomerular basement membrane, and electron microscopy showed subepithelial immune deposits. This indicates that in the initial phase of PHN, corresponding with the formation of immune complexes, a pronounced fall in RBF and GFR occurs.