Effect of dexmedetomidine on cell apoptosis during acute lung injury induced by blunt chest trauma in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of dexmedetomidine on the cell apoptosis during the acute lung injury induced by blunt chest trauma in rats.Methods Thirty pathogen-free male SpragueDawley rats,weighing 240-270 g,aged 8 weeks,were divided into 3 groups (n=10 each) using a random number table:shan operation group (group Sham),blunt chest trauma group (group T) and blunt chest trauma plus dexmedetomidine group (group TD).The model of acute lung injury was induced by dropping a 300 g weight onto a precordium in anesthetized rats.After the model was established,dexmedetomidine was intravenously infused at a rate of 5 μg · kg 1 · h-1 for 6 h in group TD.At 6 h after the model was established,blood samples were collected from the femoral artery for determination of concentrations of serum tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6).The rats were sacrificed after blood sampling,and lungs were removed for examination of the pathological changes (with light microscope) and for determination of Bax and Bcl-2 expression in lung tissues (by immuno-histochemistry) and cell apoptosis (by TUNEL).Bcl-2/Bax ratio and apoptosis index (AI) were calculated.Results Compared with group C,the serum TNF-α and IL-6 concentrations and AI were significantly increased,the expression of Bax and Bcl-2 was up-regulated,and Bcl-2/Bax ratio was decreased in T and TD groups (P＜ 0.01).Compared with group T,the serum TNF-α and IL-6 concentrations and AI were significantly decreased,the expression of Bax in lung tissues was down-regulated,the expression of Bcl-2 in lung tissues was up-regulated,Bcl-2/Bax ratio was increased (P＜0.05),and the pathological changes of lung tissues were significantly attenuated in group TD.Conclusion The mechanism by which dexmedetomidine mitigates the acute lung injury induced by blunt chest trauma is related to inhibition of cell apoptosis in rats.