11 December 2008
The dose dependency of germanium dioxide(GeO<sub>2</sub>)-induced nephrotoxicity was investigated experimentally in rat groups orally treated with high (150 mg/kg/day), moderate (75 mg/kg/day), or low (37.5 mg/kg/day) doses of GeO<sub>2</sub>, and in an untreated group. Renal dysfunction, indicated by the increase of blood urea nitrogen and the decrease of creatinine clearance, and systemic toxicity by weight loss, anemia, and hypoproteinemia were more apparent in rats treated with the higher dose of GeO<sub>2</sub>. Urinalysis including daily urinary protein excretion did not reveal any abnormalities in any of the groups. Urinary excretion and renal-tissue content of Ge were significantly elevated in the group of the higher dose of GeO<sub>2</sub>. Light microscopically, vacuolar degeneration and depositions of granules positive for periodic acid-Schiff in distal tubules were predominant in the higher-dose group of GeO<sub>2</sub>. The present study demonstrates that GeO<sub>2</sub>-induced nephrotoxicity develops dose dependently.