Renal ischemia-reperfusion-induced metabolic and micro-rheological alterations and their modulation by remote organ ischemic preconditioning protocols in the rat.

BACKGROUND: Pathomechanism and optimal renoprotective protocol for remote ischemic preconditioning (RIPC) have not been completely revealed yet. OBJECTIVE: To investigate micro-rheological effects of early and delayed RIPC in renal ischemia-reperfusion (I/R) in the rat. METHODS: In Control group the left femoral artery was cannulated and the left kidney was gently exposed. In the I/R group 45-minute renal ischemia with 120-minute reperfusion period was monitored. In the RIPC groups a 3 x 10-minute protocol was applied using tourniquet around the right hind-limb 1 hour (RIPC-1) or 24 hours (RIPC-24) prior to the I/R. Blood samples were taken for testing blood gas, acid-base, metabolic and hemorheological parameters. RESULTS: Lactate and potassium concentration significantly increased in I/R that could be reduced by RIPC, especially in RIPC-24. Creatinine concentration increased further in RIPC groups. I/R and RIPC-1 decreased the pH, RIPC-24 increased. RIPC-24 reduced the drop in base excess. Erythrocyte deformability worsened by renal I/R. In RIPC groups deformability decreased additively. However, RIPC-1 could improve the condition. RIPC-24 showed the highest erythrocyte aggregation values during reperfusion. CONCLUSIONS: Renal I/R worsened metabolic and micro-rheological parameters that could be modulated by RIPC protocols. However, it could not be decided whether the early or the delayed protocol is better.