Effects of dexmedetomidine on expression of c-fos in hippocampus and dentate gyrus in a rat model of endotoxic shock / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of dexmedetomidine on the expression of c-fos in hippocampus and dentate gyrus in a rat model of endotoxic shock.Methods Thirty-five pathogen-free healthy male Sprague-Dawley rats,aged 3-4 months,weighing 250-300 g,were divided into 5 groups (n =7 each) using a random number tablenormal saline group (group NS),dexmedetomidine group (group D),endotoxic shock group (group ES),low-dose dexmedetomidine plus lipopolysaccharide (LPS) group (group LD) and high-dose dexmedetomidine plus LPS group (group HD).Dexmedetomidine 0.5 μg/kg was injected via the tail vein in D and LD groups,and dexmedetomidine 4.5 μg/kg was given in group HD.Normal saline 0.5 ml/kg was injected in NS and ES groups,5 min later normal saline 0.5 ml/kg was injected in NS and D groups and LPS 5 mg/kg was injected in the other groups,and the injection time was 10 min in all groups.Rats were sacrificed at 6 h after LPS injection,brains were removed,and the hippocampus and dentate gyrus were isolated for detection of the expression of c-fos by immunohistochemistry.Results Compared with group NS or group D,the expression of c-fos in the hippocampus and dentate gyrus was significantly up-regulated in group ES (P＜0.05).Compared with group LPS,the expression of c-fos in the hippocampus and dentate gyrus was significantly down-regulated in LD and HD groups (P＜0.05).Compared with group LD,the expression of c-fos in hippocampal CA1 and CA3 areas was significantly down-regulated in group HD (P＜0.05).Conclusion The neuroprotective mechanism of dexmedetomidine is related to inhibiting the up-regulated expression of c-fos in the hippocampus and dentate gyrus in a rat model of endotoxic shock.