Effect of oxycodone pretreatment on autophagy during renal ischemia-reperfusion in rats

Objective To evaluate the effect of oxycodone pretreatment on autophagy during renal ischemia-reperfusion (I/R) in rats. Methods Thirty-six SPF healthy adult male Wistar rats, aged 6-9 weeks, weighing 180-220 g, were divided into 3 groups (n=12 each) using a random number table: sham operation group (Sham group), I/R group and oxycodone pretreatment group (Oxy group). The left renal pedicles were clamped with atraumatic microclips for 45 min followed by reperfusion to establish the model of renal I/R injury in I/R and Oxy groups.Oxycodone 0.5 mg/kg was injected via the caudal vein at 15 min before ischemia in group Oxy, and the equal volume of normal saline was given instead in I/R and Sham groups.At 24 h of reperfusion, blood samples were collected from hearts for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations.The animals were then sacrificed and left renal tissues were obtained for examination of pathological changes (with a light microscope) and for determination of Bcl-2 and Beclin-1 expression (by immunohistochemistry). Results Compared with Sham group, the concentrations of serum Cr and BUN were significantly increased, and the expression of Bcl-2 and Beclin-1 in renal tissues was up-regulated at 24 h of reperfusion in I/R and Oxy groups (P<0.05). Compared with I/R group, the concentrations of serum Cr and BUN were significantly decreased, the expression of Bcl-2 in renal tissues was up-regulated, and the expression of Beclin-1 in renal tissues was down-regulated at 24 h of reperfusion (P<0.05), and the pathological changes were significantly attenuated in Oxy group. Conclusion Oxycodone pretreatment inhibits autophagy through up-regulating the expression of Bcl-2 and down-regulating the expression of Beclin-1, thus attenuating renal I/R injury in rats. Key words: Oxycodone; Renal; Reperfusion injury; Autophagy