Accelerated functional recovery of isolated rat kidney with ATP-MgCl2 after warm ischemia

Isolated rat kidneys were subjected to 45, 60, and 90 min of normothermic ischemia. Kidneys reperfused with a saline solution after ischemia had very low initial whole kidney inulin clearances (Cin), urine flow rates (V), renal perfusate flow rates (RPF), and fractional absorption of sodium values that remained depressed throughout the 110 min of reperfusion. Kidneys subjected to 45 min of warm ischemia and reperfused with a solution containing 0.3 mM ATP-MgCl2 had higher initial Cin and attained complete recovery of Cin by 75 min of perfusion. Fractional absorption of sodium and water were also improved, and RPF, V, and tissue ATP levels returned to control values after 110 min of perfusion. Kidneys subjected to 60 min of ischemia and reperfused with a solution containing 0.3 mM ATP-MgCl2 also had higher initial Cin values and attained 50% recovery of Cin after 110 min of perfusion. RPF also improved, and V reached control levels. Kidneys subjected to 90 min ischemia showed no improvement in renal function even with 2 mM ATP-MgCl2. Because, even in isolated kidneys, administration of ATP-MgCl2 after 45 and 60 min of ischemia results in an early recovery of renal function, the beneficial effects of ATP-MgCl2 are exerted directly on the kidney and are not mediated via systemic effects.