Structural changes of experimental glomerulonephritis in rats as revealed by microdissection

Microdissection revealed striking alterations in the nephrons of animal models AICN and anti-GBMN. The most severely damaged AICN kidney in the series presented marked heterogeneity in the size and deformity of the proximal tubules, corresponding to the diverse and variegated nephrons described by Oliver in chronic Bright's disease. The severely damaged anti-GBMN kidneys revealed widespread alterations in the proximal tubules, which, however, tended to be fairly uniform among the affected nephrons. This uniformity, perhaps, reflected the shorter duration of disease in the anti-GBMN animals. The most characteristic proximal tubular alteration in either the AICN or anti-GBMN animals was that combining atrophy of the pars convoluta and hypertrophy of the pars recta in same tubule. The largest and smallest nephrons encountered in the entire study were found in the most severly damaged kidney in the AICN. This finding reflected the simultaneous existence of regressive and progressive changes in this kidney, as certain nephrons underwent hypertrophy to compensate for the atrophy and disappearance of others. The remarkable functional glomerulotubular balance of single nephrons known to exist in both AICN and anti-GBMN was matched by the evidence presented here of structural glomerulotubular balance among the severely altered nephrons of a representative kidney from each group. Microdissection studies directed toward the characterization of the nephronic alterations in both membranous glomerulonephritis and proliferative glomerulonephritis of man should be of interest in relation to the findings in these experimental rat models of human disease.