Effects of ionizing radiation on progressive experimental renal disease: Ahemodynamic approach

In order to evaluate the progression of renal disease, Munich-Wistar rats w ere submitted to 5/6 nephrectomy and given whole-body x- or gamma -irradiat ion with or without remnant kidney protection or were submitted only to rem nant kidney irradiation. All groups received a single 6-Gy dose immediately after surgery. Whole-kidney function, glomerular hemodynamics, 24-hour pro teinuria and histopathology were assessed 60 days after surgery and irradia tion. The irradiated nephrectomized animals presented whole-kidney function parameters comparable to those of normal rats. In addition, they were less hypertensive and had higher hematocrit. They showed glomerular hyperfiltra tion and hypertension even greater than their respective nephrectomized con trols. However, the interrelations among the glomerular filtration determin ants were somewhat different in irradiated animals. Their 24-hour proteinur ia was significantly lower and the sclerosis index and tubulointerstitial i njury score were markedly smaller. Among irradiated animals, the worst scle rosis index was observed in those with a shielded remnant kidney and the be st in those without protection of the remnant kidney. This led us to specul ate about a possible influence of resident mesangial cells on the early eve nts following renal mass ablation and on the maintenance of subsequent phys iopathologic changes. Therefore, radiation undoubtedly provoked a beneficia l change in the course of renal disease when the renal mass ablation model was employed. Many factors could have contributed to this favorable feature including lower levels of systemic arterial pressure, less increment in De ltaP, diminished proteinuria, and maintenance of tubulointerstitial space i ntegrity. Our data also suggest that development of glomerulosclerosis seem s to be determined by events occurring immediately after injury. Copyright (C) 2001 S. Karger AG, Basel.