Effects of dexmedetomidine on PI3K/Akt pathway in hippocampus of propofol anesthetized neonatal rats / 临床麻醉学杂志

ABSTRACT

Objective To explore the effect of dexmedetomidine on phosphoinositide 3-kinase/protein kinase B (PI3K/Akt ) pathway in hippocampus of propofol anesthetized neonatal rats. Methods Eighty Sprague-Dawley male rats,aged 7 days,weighing 10-1 5 g,were randomly divided into 8 groups (n= 10 each):normal saline group (group N),DMSO group (group D),intralipid group (group I),propofol group (group P),dexmedetomidine 25 μg/kg,50 μg/kg and 75 μg/kg +propofol 100 mg/kg groups (groups PD25 ,PD50 and PD7 5 ),LY294002 25 μg + dexmedetomidine 75μg/kg + propofol 100 mg/kg group (group LYPD).The hippocampus of rats in all groups were taken 2 h after the animals fully awake.The ultrastructure of hippocampal neurons was observed by transmission electron microscope.The pAkt-(ser473 )protein and Akt protein in the hippocampus were evaluated by Western blot analysis.Results There was no significant difference in the expression of Akt protein among the eight groups.Compared with group N,the expression of pAkt (ser473)protein was significantly down-regulated in groups P,PD25 ,PD50 ,PD7 5 and LYPD (P <0.05).Compared with group P,the expression of pAkt (ser473)protein was increased significantly in groups PD7 5 and LYPD (P <0.05).Compared with group PD7 5 ,the expression of pAkt (ser473) protein was significantly down-regulated in group LYPD (P <0.05 ).The structure of hippocampal neurons was normal in groups N,I and D.Nuclear nuclei swelling,chromatin decreasing and mito-chondrion vacuolar degeneration were observed in group P while improved gradually with dexmedeto-midine in a dose-dependent manner in groups PD25 ,PD50 and PD7 5 .Neurons karyopyknosis,partial dissolution of nuclear membrane,chromatin condensation,mitochondria vacuolar degeneration were observed in group LYPD.Conclusion Dexmedetomidine pretreatment provides neuroprotection against propofol-induced hippocampal destruction by preserving PI3K/Akt pathway activity in the de-veloping brains.