激动髓样细胞-2触发受体减轻围术期神经认知障碍

Activating myeloid 2 trigger receptor to alleviate perioperative neurocognitive impairment 2

目的研究髓样细胞-2触发受体(TREM2)是否参与成年小鼠手术诱发的围术期神经认知障碍(PND)。方法将20只雄性野生型C57BL/6小鼠随机分为对照组和手术组各10只,在手术前24小时对小鼠进行恐惧条件训练,恐惧条件测试(FCT)分别在术后1、3和7天进行,并采用旷场实验评估小鼠的运动能力。在最后一次行为评估后,将动物处死进行Western blot检测TREM2的表达。将40只小鼠随机分为对照组、手术组、Hsp60+手术组和TREM2-siRNA+HSP60+手术组,每组各10只。手术前30分钟将TREM2-siRNA立体定向注射入侧脑室。选择性TREM2受体激动剂HSP60,在麻醉苏醒后立即腹腔注射5μg/小鼠,按前述方法每24小时注射一次,连续7天,在手术前24小时对小鼠进行恐惧条件训练,FCT分别分别在术后1、3和7天进行,并采用旷场实验评估小鼠的运动能力。在最后一次行为评估后,一半小鼠(n=5)用于Western blot和ELISA分析,另一半(n=5)用于免疫荧光检测。结果在异氟烷麻醉下对成年C57BL/6小鼠行胫骨骨折髓内固定术,发现该手术不会损害小鼠的运动能力,但会恶化学习和记忆功能,并降低TREM2表达。通过使用选择性TREM2激动剂HSP60,发现TREM2在小鼠脑海马组织中的表达明显增加,从而改善了学习和记忆,并减轻了小鼠的神经炎症反应。TREM2-siRNA消除了HSP60诱导的TREM2表达的增加,并逆转了HSP60诱导的小鼠学习和记忆功能以及小鼠脑神经炎症水平的改善。结论TREM2的上调可能与减轻神经炎症和改善学习记忆功能有关,并减少PND的发生。

Objective To investigate whether Triggering Receptor Expressed on Myeloid cells 2(TREM2)is involved in perioperative neurocognitive disorders in adult mice.Methods Twenty male wild-type C57BL/6 mice were randomly divided into control group and operation group(n=10).Fear conditioning training was performed 24 hours before operation,and fear conditioning test(FCT)was performed on 1,3 and 7 days after operation.Open field test was used to evaluate the motor ability of mice.After the last behavioral evaluation,the animals were killed and the expression of TREM2 was detected by Western blot.Forty mice were randomly divided into four groups(n=10):control group,operation group,heat shock protein 60(Hsp60)+operation group and TREM2 siRNA+Hsp60+operation group.TREM2 siRNA was stereotaxically injected into the lateral ventricle 30 minutes before operation.HSP60,a selective TREM2 receptor agonist,was injected intraperitoneally for 5 minutes immediately after anesthesiaμThe mice were given fear conditioning training 24 hours before operation,and FCT was performed 1,3 and 7 days after operation respectively.The open field test was used to evaluate the motor ability of the mice.After the last behavioral evaluation,half of the mice(n=5)were used for Western blot and ELISA analysis,and the other half(n=5)were used for immunofluorescence detection.Results Intramedullary fixation of tibial fracture in adult C57BL/6 mice was performed under isoflurane anesthesia.It was found that the operation did not damage the movement ability of mice,but worsened the learning and memory function and decreased the expression of TREM2.Through the use of selective TREM2 agonist HSP60,we found that the expression of TREM2 in the hippocampus of mice was significantly increased,which improved learning and memory,and reduced the neuroinflammatory response of mice.However,TREM2 siRNA abolished the Hsp60 induced increase of TREM2 expression and reversed the Hsp60 induced improvement of learning and memory function and neuroinflammation in mice.Conclusion Up-regulation of TREM2 may be associated with alleviated neuroinflammation and improved learning and memory function,and reducing the occurrence of PND.