The influence of dexmedetomidine pretreatment on global cerebral ischemic-reperfusion injury in rats

doi:10.3969/j.issn.1002-7386.2015.17.001

Abstract：Objective To observe the protective effect of different doses of dexmedetomidine by means of pretreatment on brain in rats.Methods The animal models with global cerebral ischemia were established by four-vessel occlusion in male SD rats. The rat models were randomly divided into 4 groups:sham-operation group ( group S );ischemic-reperfusion control group (group C);low and medium doses of dexmedetomidine groups (group D1,group D2),with 10 rats in each group.The rats in group D1and group D2,on 2 hours before ischemia,were infused with dexmedetomidine 0.05 and 0.5μg· kg-1 · min-1 , respectively,however,the rats in group S and group C were given 0.9%sodium chloride solution 2ml/h instead.The brain water content was measured by wet-dry weight method.The pathological changes and cell ultrastructure changes in hippocampal CA1 region were observed 30 min after reperfusion.Results As compared with that in group S,the brain water content was significantly increased in group C,D1 and D2 ( P <0.05),however,there was no significant difference between group C and D1,group D2 ( P >0.05)A.s compared with those in group C ,the neuronal cells in group D1 were damaged,most pyramidal cells were survial,the number of shrinkage neuronal cell was decreased.The most severe pathological changes were observed in group C, with nerve cells surrounding edema,cytoplasmic edema . The mitochondrial electron density was increased, and swelling, cristae rupture were disappeared. The Golgi vesicles were expanded.The astrocytes were obvious swelling.Capillary endothelial cells were swelling, with perivascular edema.As compared with those in group C, the pathological changes in group D1and group D2 were alleviated, but there were no significant differences between group D1 and group D2.Conclusion The low-dose and midium-dose dexmedetomidine pretreatment has certain protective effects on global cerebral ischemia-reperfusion injury in rats, with ultrastructural organelles swelling being alleviated,however there is no significant difference between the two groups.