Effect of dexmedetomidine on scalds-induced acute lung injury in rats

Abstract

Objective To evaluate the effect of dexmedetomidine on acute lung injury induced by scalds in rats. Methods Seventy-five male Sprague-Dawley rats, weighing 200-220 g, were randomly divided into 5 groups(n=15 each)using a random number table: control group(group C), scald group(group S), dexmedetomidine group(group D), α-bungarotoxin(α-BGT)group, and dexmedetomidine+ α-BGT group(group D+ α-BGT). About 30% of the total body surface was shaved and then exposed to 98 ℃ water for 12 s in S, D, α-BGT and D+ α-BGT groups.The back of rats was exposed to 37 ℃ water for 12 s in group C. Rats were resuscitated with lactated Ringer's solution injected intraperitoneally according to Parkland formula within 24 h after establishment of the model.In D, α-BGT, and D+ α-BGT groups, dexmedetomidine 40 μg/kg, α7 nicotinic acetylcholine receptor antagonist α-BGT 1 μg/kg, and α-BGT 1 μg/kg plus dexmedetomidine 40 μg/kg were injected intraperitoneally, respectively, at 15 min before establishment of the model.At 24 h after establishment of the model, the rats were sacrificed, and lungs were removed for examination of the pathological changes and for determination of myeloperoxidase(MPO)activity, interleukin-1beta(IL-1β), tumor necrosis factor-alpha(TNF-α), and IL-6 contents(by enzyme-linked immunosorbent assay), and nucleoprotein factor kappa B(NF-κB)(by Western blot). The lung water content [(wet weight-dry weight)÷wet weight×100%] was calculated. Results Compared with group C, the lung water content, MPO activities, and contents of IL-1β, TNF-α and IL-6 were significantly increased, and the expression of NF-κB was up-regulated in S, α-BGT and D groups(P 0.05), and the pathological changes were significantly attenuated in group α-BGT.Compared with group D, the lung water content, MPO activities, and contents of IL-1β, TNF-α and IL-6 were significantly increased, the expression of NF-κB was up-regulated(P<0.05), and the pathological changes were aggravated in group D+ α-BGT. Conclusion Dexmedetomidine can mitigate scalds-induced acute lung injury in rats. Key words: Dexmedetomidine; Burns; Respiratory distress syndrome, adult