蓝斑小胶质细胞参与调控异氟醚致意识转换的全身麻醉过程

Microglia in the locus coeruleus involved in modulation of isoflurane-induced consciousness shift during general anesthesia

目的探究蓝斑小胶质细胞活性变化与吸入麻醉药异氟醚致意识转换的相关性及全身麻醉过程中的作用机制。方法选取雄性C57BL/6J小鼠24只,随机分为对照组(n=12)及米诺环素组(n=12)。通过双侧蓝斑核内微注射小胶质抑制剂米诺环素/生理盐水,抑制蓝斑核小胶质细胞活性。免疫荧光染色观察小胶质细胞在蓝斑的分布及激活情况。两组实验鼠均安置脑电图记录电极,记录小鼠在1.4%异氟醚全麻过程中翻正反射消失(LORR)时间、翻正反射恢复(RORR)时间及脑电图(EEG)变化。结果(1)蓝斑微注射米诺环素后,蓝斑小胶质细胞活性被抑制;(2)在异氟醚全麻诱导期,米诺环素组较对照组LORR时间显著延长,EEG表现为δ波显著减少,γ波增加,而β波无明显变化;(3)在全麻恢复期,米诺环素组较对照组RORR时间显著缩短,EEG表现为δ波显著减少,β波增加,而γ波无明显变化;(4)在全麻维持期,相较于对照组,米诺环素处理后爆发抑制率(BSR)的结果无统计学差异。结论特异性抑制蓝斑小胶质细胞活性可阻碍小鼠异氟醚全麻诱导并加速复苏,这可能与麻醉状态下抑制小胶质细胞活性后蓝斑神经元活动被激活有关。

Objective To explore the correlation between changes in locus coeruleus microglial activity and isoflurane-induced consciousness shift,as well as the underlying mechanism during general anesthesia.Methods Twenty-four male C57BL/6J mice were randomly divided into Control group(n=12)and Minocycline group(n=12).The microglial activation inhibitor minocycline/saline was microinjected bilaterally into the locus coeruleus(LC)to inhibit microglial activity.Immunofluorescence staining was performed to validate the distribution and activation of microglia in the LC in both groups.All experimental mice were implanted with electroencephalogram(EEG)recording electrodes to monitor loss of righting reflex(LORR)period,recovery of righting reflex(RORR)period,and EEG signals during 1.4%isoflurane anesthesia.Results(1)After microinjection of minocycline into LC,it has been shown to inhibit microglial activation;(2)Compared to the Control group,minocycline microinjection prolonged the LORR time during the induction period of 1.4%isoflurane.EEG analysis showed a striking decrease inδpower and an increase inγpower,while there was no significant change inβpower in Minocycline group;(3)During the recovery period,the RORR time in Minocycline group was significantly shortened compared to Control group.EEG analysis showed a significant decrease in ratio ofδbands and an increase in ratio ofβbands,while there was no significant change inγwaves in minocycline group;(4)There was no statistical difference in burst suppression rate(BSR)between Minocycline and Control group during isoflurane maintenance.Conclusion Inactivation of microglia in the LC mediated inhibition of induction and facilitation of emergence from isoflurane anesthesia in mice,which could potentially be associated with LC neuronal activity that was enhanced following suppression of microglial activity by minocycline during general anesthesia.