Amelioration of Radiation Nephropathy by Acetylsalicylic Acid

Abstract

This investigation was carried out to assess the amelioration by two antithrombotic drugs of radiation nephropathy in mice. Mouse kidneys were given split-dose irradiation to total doses between 17 and 22 Gy. A first group of animals was given acetylsalicylic acid (ASA) in drinking water, a second received daltroban, a thromboxane A₂/prostaglandin H₂ receptor antagonist, and a third received normal tap water, serving as a control. Both antithrombotic drugs were started 1 week prior to the irradiation and were given throughout the whole follow-up period. Renal function was assessed every 4 weeks from 18 weeks after the start of irradiation onwards by measuring the [⁵¹Cr] EDTA retention and haematocrit. The dose of ASA (600 mg/kg/day) caused an inhibition of thromboxane A₂ and prostacyclin biosynthesis to 19 ± 10 (mean ± SEM) and 85 ± 22%, respectively, as assessed by the excretion of their urinary metabolites. A significant sparing effect on the renal function after irradiation was observed in the ASA-treated animals. Using the latency time to reach 4% residual plasma activity of [⁵¹Cr] EDTA, a dose-modifying factor of 1·19 was calculated. No effect was seen with daltroban (10 mg/kg/day). Histopathological analysis of the kidneys at 12 months after irradiation demonstrated a substantially lower level of damage in the ASA-treated mice compared with daltroban-treated and radiation-only animals. These data indicate that long-term treatment with ASA is effective in reducing renal functional impairment after irradiation.