Progressive glomerular injury after limited renal infarction in the rat

Abstract

Wistar Munich rats subjected to partial renal ablation were compared with intact rats. Group 1 rats were subjected to bilateral segmental infarction of 40% of their total renal mass. Group 2 rats underwent uninephrectomy. Group 3 rats underwent sham operation. Micropuncture and morphological studies were performed in each group at 28 wk after operation. In group 1, glomerular capillary pressure was elevated by 7 mmHg and systemic blood pressure was elevated by 31 mmHg despite reduction of nephron number by only 40% and reduction of glomerular filtration rate (GFR) by only 10%. Progressive albuminuria and segmental glomerular sclerosis were associated with elevation of glomerular capillary pressure in this group. In group 2, single-nephron glomerular filtration rate (SNGFR) was higher than in group 1, but systemic and glomerular capillary pressure remained normal. Group 2 rats developed markedly less albuminuria and glomerular sclerosis than group 1 rats despite more pronounced remnant nephron hyperfiltration. These studies support the view that glomerular hypertension is the major hemodynamic derangement contributing to remnant glomerular injury and show that capillary hypertension can initiate remnant glomerular injury even when the majority of the renal mass remains intact.