Effect of dexmedetomidine pretreatment on activation of JAK/STAT signaling pathway during intestinal injury in rats undergoing liver transplantation / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of dexmedetomidine pretreatment on activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway during intestinal injury in rats undergoing liver transplantation.Methods Thirty-two pathogen-free healthy adult male Sprague-Dawley rats,weighing 220-250 g,aged 8-10 weeks,were divided into 4 groups (n =8 each) using a random number tablesham operation group (S group),liver transplantation group (LT group),dexmedetomidine pretreatment group (D group) and dexmedetomidine plus atipamezole (specific α2-adrenergic receptor antagonist) group (D+A group).The model of liver transplantation was established in LT,D and D+A groups except group S.In group D,dexmedetomidine 50 μg/kg was injected intraperitoneally at 30 min before skin incision.In group D+A,atipamzole 250 μg/kg was injected intraperitoneally at 5 min before administration of dexmedetomidine.At 6 h of reperfusion,blood samples were collected from the inferior vena cava for determination of serum concentrations of intestinal fatty acid binding protein (iFABP),lipopolysaccharide (LPS),tumor necrosis factor-alpha (TNF-ct) and high-mobility group box 1 protein (HMGB1).Intestinal specimens were then obtained for examination of the pathological changes of intestinal tissues (under light microscope) and for determination of the expression of activated caspase-3,phosphorylated JAK2 (p-JAK2),phosphorylated STAT1 (p-STAT1) and phosphorylated STAT3 (p-STAT3).Intestinal damage was assessed and scored.Wet/dry weight ratio (W/D ratio) was calculated.Results Compared with group S,the concentrations of iFABP,LPS,TNF-α and HMGB1 in serum,intestinal damage scores and W/D ratio were significantly increased,and the expression of activated caspase-3,p-JAK2,pSTATI and p-STAT3 in intestinal tissues was up-regulated in LT and D groups (P＜0.05).Compared with group LT,the concentrations of iFABP,LPS,TNF-cα and HMGB1 in serum,intestinal damage scores and W/D ratio were significantly decreased,and the expression of activated caspase-3,p-JAK2,p-STAT1 and p-STAT3 in intestinal tissues was down-regulated in group D (P＜0.05).Compared with group D,the concentrations of iFABP,LPS,TNF-cα and HMGB1 in serum,intestinal damage scores and W/D ratio were significantly increased,and the expression of activated caspase-3,p-JAK2,p-STAT1 and p-STAT3 in intestinal tissues was up-regulated in group D+A (P＜0.05).The pathological changes of intestinal tissues were significantly attenuated in group D as compared with group LT.Conclusion The mechanism by which dexmedetomidine pretreatment reduces intestinal injury may be related to inhibition of JAK/STAT signaling pathway activation in rats undergoing liver transplantation.