Effect of dexmedetomidine on lipid peroxidation during lung ischemia-reperfusion in rats

Objective To evaluate the effect of dexmedetomidine on lipid peroxidation during lung ischemia-reperfusion (I/R) in rats. Methods Fifty-four pathogen-free healthy male Wistar rats, weighing 250-350 g, were randomly divided into 3 groups (n=18 each) using a random number table: sham operation group (S group), I/R group, and dexmedetomidine group (Dex group). In group Dex, dexmedetomidine 5 μg/kg was injected via the caudal vein once a day for 2 consecutive days.The equal volume of normal saline was given in S and I/R groups.At 30 min after administration on 2nd day, lung I/R was produced by clamping the left hilum of lung for 45 min followed by 120 min of reperfusion in I/R and Dex groups.At 45 min of ischemia, and 60 and 120 min of reperfusion, 6 rats selected from each group were sacrificed, and the left lungs were removed for examination of the pathological changes and for determination of wet/dry lung weight ratio (W/D ratio), malondialdehyde (MDA) content and superoxide dismutase (SOD) activity. Results Compared with S group, the SOD activity was significantly decreased, and the MDA content and W/D ratio were significantly increased at 60 and 120 min of reperfusion in I/R and Dex groups (P<0.05). Compared with I/R group, the SOD activity was significantly increased, and the MDA content and W/D ratio were significantly decreased at 60 and 120 min of reperfusion in Dex group (P<0.05). The pathological changes of lungs were significantly attenuated in Dex group as compared with I/R group. Conclusion Dexmedetomidine mitigates lung I/R injury through inhibiting lipid peroxidation in rats. Key words: Dexmedetomidine; Lung; Reperfusion injury; Lipid peroxidation