Effects of different doses of remifentanil on renal ischemia-reperfusion injury in rats

Objective To investigate the effects of different doses of remifentanil on the renal ischemiareperfusion (I/R) injury in rats. Methods Sixty male SD rats weighing 220-250 g were randomly divided into 5 groups ( n = 12 each): sham operation group (group S), model group (group M), low, median and high doses of remifentanil groups (RL, RM and RH groups). The rats were anesthetized with intraperitoneal 5% chloral hydrate 6 ml/kg. Renal ischemia was induced by clamping the bilateral renal arteries for 45 min using an atraumatwere infused via the caudal vein 15 min before ischemia respectively and the infusion was stopped at 30 min of reperfusion, while S and M groups received equal volume of normal saline instead. Blood samples were collected from the femoral vein at 30 min and 24 h of reperfusion for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations. The rats were sacrificed at 24 h of reperfusion and the renal tissues were removed for determination of MDA content, SOD and Ca2+ -ATPase activities. Pathological changes in renal tissues were observed with light and electron microscopes. Results Compared with group S, the concentrations of serum Cr and BUN and content of MDA were significantly increased, while activities of SOD and Ca2+ -ATPase were significantly decreased in the other 4 groups ( P ＜ 0.05 or 0.01). Compared with group M, the concentrations of serum Cr and BUN and content of MDA were significantly decreased, activities of SOD and Ca2+ -ATPase were significantly increased (P ＜0.05 or 0.01) and the pathological changes were reduced in RH, RM and RL groups. The plasma BUN and Cr concentrations and MDA content were decreased gradually and SOD and Ca2+ -ATPase activities were increased gradually with the increase in the doses of remifentanil in RL, RM and RH groups ( P ＜ 0.05 or 0.01 ).Remifentanil infusion significantly attenuated the pathologic changes in a dose-dependent manner. Conclusion Remifentanil can reduce the renal I/R injury in a dose-dependent manner by inhibiting lipid peroxidation and increasing Ca2+ -ATPase activity. Key words: Piperidines;  Reperfusion injury;  Kidney