The effect of saline loading on uranium-induced acute renal failure in rats

Abstract

Studies were performed to examine the effect of saline loading on uranium-induced acute renal failure (ARF) in rats. Forty-eight hours after the i.v. injection of uranyl acetate (UA, 5 mg/kg), inulin clearance rate (C(in)) decreased to approximately 43% of the control value in water drinking rats (P < 0.005). Animals receiving continuous isotonic saline infusion following UA showed higher urine flow and C(in) (60% of control, P < 0.01), and lessened intratubular cast formation when compared with water-drinking ARF rats. A short-term saline infusion following UA did not attenuate the decline in C(in) (43% of control). An inverse relationship was found between C(in) and the number of casts (r = -0.75, P < 0.001). Multiple regression analysis showed that standardized partial regression coefficient is statistically significant between C(in) and cast formation (-0.69, P < 0.05), but not between C(in) and tubular necrosis (-0.07, P > 0.05). Renin depletion caused by DOCA plus saline drinking did not attenuate the decline in C(in) in ARF (47% of control). No significant difference was found in urinary uranium excretion between water-drinking and saline-infused ARF rats. The findings suggest that continuous saline infusion following UA attenuates the decline in C(in) in ARF rats; and that this beneficial effect of saline loading is associated with lessened cast formation raher than with suppressed renin-angiotensin activity or enhanced urinary-uranium excretion.