Effect of dexmedetomidine on apoptosis in myocardial cells in rats with severe scald

Objective To evaluate the effect of dexmedetomidine on apoptosis in myocardial cells in rats with severe scald.Methods Eighteen healthy male Sprague-Dawley rats,weighing 220-280 g,were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),scald group (group B)and scald + dexmedetomidine 30 μg/kg group (group D).Thirty percent of the total body surface was shaved and then exposed to 94 ℃ water for 12 s.Rats were resuscitated with isotonic saline according to Parkland formula immediately after burn.Sham burn was produced in C group.In group D,the rats received inraperitoneal injection of dexmedetomidine 30 μg/kg immediately after burn,and the equal volume of normal saline was injected in group B.The left ventricle was removed at 12 h after burn to observe the pathological changes of myocardial tissues with light microscope and to detect the apoptosis in myocardial cells (TUNEL assay) and expression of glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP) (using Western blot).The apoptosis index was calculated.Results Compared with group C,the apoptosis index was significantly increased and the expression of GRP78 and CHOP was up-regulated in B and D groups (P ＜ 0.05).Compared with group B,the apoptosis index was significantly decreased and the expression of GRP78 and CHOP was down-regulated in group D (P ＜ 0.05).The pathological changes were obvious in group B and were significantly attenuated in group D.Conclusion Dexmedetomidine can protect myocardium through inhibiting endoplasmic reticulum stress-mediated apoptosis in myocardial cells in rats with severe scald. Key words: Dexmedetomidine ;  Burns ;  Myocardium ;  Apoptosis