Renal failure in high altitude: renal functions, renal pathology and bone mineralization in rats with ablation nephropathy at 1200 m altitude.

The effect of altitude on renal failure and bone mineralization is not well known. This topic is studied in a 5/6 nephrectomy rat model. After hemoglobin, creatinine clearance and proteinuria were determined in 28 Wistar rats. Two 5/6 nephrectomy (Nx1-Nx2, n=7 each) and two sham (Sh1-Sh2, n=7 each) groups were formed. The Nx1-Sh1 and Nx2-Sh2 groups were kept at sea level and at 1200 m altitude, respectively. The same analyses were performed after 3 months just before sacrifices in order to harvest kidneys and femurs for histopathologic examination. Hemoglobin, creatinine clearance, and proteinuria were similar in all groups at the onset. Final hemoglobin was higher in Nx2-Sh2, but only Sh2 vs. Sh1 was significant (p=0.001). Creatinine clearance decreased (p=0.001 for Nx1) and proteinuria increased (p=0.002 for Nx1 and p=0.005 for Nx2) after 5/6 nephrectomy, but Nx1 vs. Nx2 was similar. Histopathological changes in the remnant kidneys were prominent, but Nx1 vs. Nx2 was not different. Although the relative osteoid volume increased in Nx groups, only Nx1 vs. Sh1 was different (p=0.006). In conclusion, exposure to 1200 m altitude, compared to the sea level, preserved the creatinine clearance better in 5/6 nephrectomized rats. No change was observed in proteinuria, renal histopathology, and bone mineralization.