Effects of dexmedetomidine pretreatment and postconditioning on renal ischemia-reperfusion injury in rats

Objective To investigate the effects of dexmedctomidine pretreatment and postconditioning on renal ischemia-reperfusion (I/R) injury in rats.Methods Thirty-two male Wistar rats,aged 3-4 months,weighing 220-300 g,were randomly divided into 4 groups ( n =8 each):sham operation group ( group S),I/R group,dexmedetomidine pretreatment group (group Pre) and dexmedetomidine postconditioning group (group Post).The rats were anesthetized with phenobarbital sodium 65 mg/kg.Renal I/R was produced by occlusion of both renal pedicles for 60 min followed by 48 h reperfusion.Dexmedetomidine 50 μg/kg was given intraperitoneally at 30 min before ischemia and at the beginning of reperfusion in Pre and Post groups respectively.The concentrations of serum creatinine and blood urea were determined at 0,24 and 48 h of reperfusion (T1-3).The renal tissues were obtained at the end of reperfusion for microscopic examination and detection of apoptosis by TUNEL assay.Acute kidney tubular necrosis was scored and apoptosis index (AI) was calculated.Results Compared with group S,the concentration of serum creatinine and blood urea at T2.3,and acute kidney tubular necrosis score and AI were significantly increased in I/R,Pre and Post groups ( P ＜ 0.05).Compared with I/R group,the concentration of serum creatinine and blood urea at T2.3,acute kidney tubular necrosis score and AI were significantly decreased in Pre and Post groups ( P ＜ 0.05).Conclusion Both dexmedetomidine pretreatment and postconditioning can attenuate renal I/R injury through inhibition of cell apoptosis in rats. Key words: Dexmedetomidine;  Reperfusion injury;  Kidney diseases