In rats with experimental glomerulonephritis, single nephron filtration rates were highly heterogeneous but maintained almost complete glomerulotubular balance, with mean SNGFR significantly reduced in acute anti-GBM nephritis compared to controls.
Experimental models of glomerulonephritis demonstrate marked heterogeneity in single nephron function while maintaining glomerulotubular balance despite severe architectural derangement.
Absolute Event Rate: 19.4% vs 40.6%
p-value: p=<0.001
Micropuncture, clearance, immunofluorescence and light microscopy techniques were used to study kidney structure and single nephron function in rats with autologous immune complex nephritis (AICN), a membranous glomerulonephritis developing over 5 to 20 mo, in the more acute and proliferative glomerular basement membrane (GBM) nephritis and in controls. Both models are known to have clinical counterparts in human disease. Kidney functional abnormalities correlated with the degree of architectural derangement. In both AICN and anti-GBM nephritis filtration fraction fell in direct proportion to the fall in glomerular filtration rate (GFR), renal plasma flow being unchanged. Fractional electrolyte excretion increased as the GFR fell. Despite marked heterogeneity of single nephron filtration rate (SNGFR) (AICN, 5-93 nl/min; anti-GBM, 0-50 nl/min) and of proximal tubular hydrostatic pressure (4-48 mm Hg), each nephron showed almost complete glomerulotubular balance, absolute reabsorption to the late proximal convolution varying directly with filtration rate. In addition SNGFR could be related both to proximal intratubular hydrostatic pressure and to calculated glomerular capillary pressure (Pg), being lowest in those nephrons with the highest intratubular pressure. Nephrons with very high filtration rates did not apparently reach filtration equilibrium. Mean SNGFR was significantly lower in the anti-GBM group, while calculated Pg was the same in both. This probably reflects the acute and diffuse involvement of the anti-GBM lesion with different filtration characteristics from the more chronic AICN disease. Tubular damage was more marked in AICN, and extraction of p-aminohippurate was reduced in this group.
Allison et al. (Wed,) conducted a other in Experimental Glomerulonephritis (n=77). Induction of autologous immune complex nephritis (AICN) or anti-GBM nephritis vs. Control rats (CFA alone or no injection) was evaluated on Single nephron glomerular filtration rate (SNGFR) (p=<0.001). In rats with experimental glomerulonephritis, single nephron filtration rates were highly heterogeneous but maintained almost complete glomerulotubular balance, with mean SNGFR significantly reduced in acute anti-GBM nephritis compared to controls.