右美托咪啶对老年患者术后认知功能和围术期单核细胞Toll样受体2和Toll样受体4表达的影响

目的 探讨右美托咪啶对老年患者术后认知功能和围术期单核细胞Toll样受体2(TLR2)和TLR4表达的影响.方法 择期手术治疗的腰椎间盘突出症和腰椎骨折患者45例,年龄≥65岁,体重53～72 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为3组(n=15):对照组(Ⅰ组)和不同剂量右美托咪啶组(Ⅱ组和Ⅲ组).麻醉诱导结束后静脉输注右美托咪啶负荷剂量1.0μg/kg,输注时间15 min,然后以0.5μg/·kg-1·h-1(Ⅱ组)或1.0 μg·Jg-1·h-1(Ⅲ组)的速率静脉输注至术毕,Ⅰ组给予等容量生理盐水.于麻醉诱导前(T1)、手术开始1.5 h(T2)、术毕(T3)和术后24 h(T4)时取静脉血样,检测外周血单核细胞TLR2及TLR4的表达.分别于术前1d和术后7d时采用简易精神状态量表评分和韦氏成人记忆量表及智力量表评价认知功能,记录术后认知功能障碍的发生情况.结果 与Ⅰ组比较,Ⅱ组和Ⅲ组术后认知功能障碍发生率降低,T2～T4时单核细胞TLR2和TLR4表达下调(P＜0.05)；与Ⅱ组比较,Ⅲ组术后认知功能障碍发生率降低,T～T4时单核细胞TLR2和TLR4表达下调(P＜0.05).结论 右美托咪啶可预防老年患者POCD的发生,其机制与抑制单核细胞TLR2和TLR4的表达有关.

Effects of dexmedetomidine on postoperative cognitive function and monocytes Toll-like receptor 2 and Tolllike receptor 4 expression in elderly patients

Objective To investigate the effects of dexmedetomidine on postoperative cognitive function and monocytes Toll-like receptor 2 (TLR2)and TLR 4 expression in elderly patients.Methods Forty-five ASA Ⅰ or Ⅱ elderly patients aged ≥65 yr weighing 53-72 kg were randomly divided into 3 groups: control group (group Ⅰ ) and different doses of dexmedetomidine groups(groups Ⅱ and Ⅲ ).Dexmedetomidine 1.0 μg/kg was injected iv over 15 min after anesthesia induction,and then was infused at a rate of 0.5 μg·kg-1 ·h-1 (group Ⅱ ) or 1.0 μg· kg-1 ·h-1 (group Ⅲ ) untile the end of operation.Group Ⅰ received equal volume of normal saline.Blood samples were taken before anesthesia induction,at 1.5 h after the beginning of operation,at the end of operation and at 24 h after operation(T,-T5 ) for determination of monocytes TLR2 and TLR4 expression by flow cytometrybased method.Postoperative cognitive function was evaluated at 1 d before and 7 d after operation with Mini-mental state examination and Wechsler memory scale and Wechsler adult intelligence scale,and the postoperative cognitive dysfunction was recorded.Results The incidence of postoperative cognitive dysfunction and monocytes TLR2 and TLR4 expression were significantly lower in groups Ⅱ and Ⅲ than in group Ⅰ,and in group Ⅲ than in group Ⅱ (P ＜ 0.05).Conclusion Dexmedetomidine can prevent postoperative cognitive dysfunction in elderly patients,and the mechanism may be related to down-regulation of monocytes TLR2 and TLR4 expression.