Effect of oxycodone preconditioning on liver injury induced by intestinal ischemia-reperfusion in rats and the role of different opioid receptors

Objective To evaluate the effect of oxycodone preconditioning on liver injury induced by intestinal ischemia-reperfusion (I/R) in rats and the role of different opioid receptors. Methods Fifty-four adult male Sprague-Dawley rats, weighing 200–300 g, were randomly divided into 9 groups (n = 6 each) using a random number table: sham operation group (group S), group I/R, oxycodone preconditioning group (group OP), μ receptor antagonist CTOP group (group CTOP), δ receptor antagonist naltrindole group (group NTD), κ receptor antagonist nor-binaltorphimne group (group BNI), CTOP + oxycodone preconditioning group (group CTOP+ OP), naltrindole + oxycodone preconditioning group (group NTD+ OP), and nor-binaltorphimne + oxycodone preconditioning group (BNI+ OP). The model of intestinal I/R was established by occlusion of the superior mesenteric artery for 45 min followed by 2 h reperfusion in anesthetized rats.The superior mesenteric artery was only exposed, but not occluded in group S. In OP, COTP+ OP, NTD+ OP and BNI+ OP groups, oxycodone 0.5 mg/kg was injected intravenously at 10 min prior to ischemia.COTP 1 mg/kg and naltrindole 5 mg/kg were injected intravenously at 20 min prior to ischemia in COTP+ OP and NTD+ OP groups, respectively.Nor-binaltorphimne 5 mg/kg was injected intravenously at 25 min prior to ischemia in group BNI+ OP.In CTOP and NTD groups, the corresponding doses of CTOP and naltrindole were injected intravenously at 10 min prior to ischemia.In group BNI, the corresponding dose of nor-binaltorphimne was injected intravenously at 15 min prior to ischemia.The rats were sacrificed at 2 h of reperfusion, and left hepatic lobes were removed for microscopic examination and for detection of apoptosis in liver cells (using TUNEL). The apoptosis index (AI) was calculated. Results Compared with group S, the AI was significantly increased in the other groups (P 0.05). Compared with group OP, the AI was significantly increased (P 0.05). Conclusion Oxycodone preconditioning can mitigate liver injury induced by intestinal I/R in rats, and μ, δ and κ receptors mediate the role with comparable effects. Key words: Oxycodone; Ischemic preconditioning; Reperfusion injury; Intestines; Receptors, opioid; Liver injury