依替福辛对术后认知功能障碍小鼠的认知保护作用及机制

Preventive effects of etifoxine on POCD in mice and its action mechanism

目的探讨转位蛋白18 kDa(TSPO18 kDa)的配体依替福辛(etifoxine,EFX)对术后认知功能障碍(POCD)小鼠的认知保护作用及机制。方法将老年雄性C57BL/6J小鼠随机分为对照组(Control组)、POCD组、POCD+EFX组、POCD+EFX+FIN(非那司提)组,其中非那司提是四氢孕酮的合成抑制剂。小鼠行连续4 d水迷宫隐蔽平台训练实验。POCD+EFX组训练前先进行3 d的依替福辛(50 mg/kg)腹腔注射;POCD+EFX+FIN组训练前先注射3 d的依替福辛(50 mg/kg)和非那司提(5 mg/kg)。隐蔽平台试验训练完成后POCD组、POCD+EFX组、POCD+EFX+FIN组进行肝叶切除术。术后第3天和第7天进行水迷宫探索实验。然后将小鼠处死,取海马进行实验室检测。结果术后3 d时空间探索实验显示:与对照组比较,POCD组小鼠在目标象限停留时间和游泳距离显著缩短(P<0.01);与POCD组比较,POCD+EFX组小鼠在目标象限停留时间和游泳距离明显延长(P<0.05);使用非那司提拮抗后,小鼠在目标象限游泳距离再次缩短(P<0.05)。术后3 d海马TSPO蛋白检测结果显示:与对照组比较,POCD组小鼠海马TSPO水平显著升高(P<0.05);POCD+EFX组小鼠TSPO蛋白水平与POCD组比较显著降低(P<0.01);使用非那司提拮抗依替福辛的作用后,TSPO蛋白水平虽有增加,但差异无统计学意义(P>0.05)。术后3 d时4组小鼠海马组织中TNF-α、IL-1β细胞因子检测结果显示:与对照组比较,POCD组小鼠TNF-α、IL-1β水平显著升高(P<0.05或<0.01);与POCD组比较,依替福辛预处理可显著降低TNF-α、IL-1β水平(P<0.05);使用非那司提拮抗后,IL-1β水平又显著升高(P<0.05),TNF-α蛋白水平虽有所升高,但差异无统计学意义(P>0.05)。术后3 d四氢孕酮含量检测结果显示:与对照组比较,POCD组小鼠海马内四氢孕酮含量显著降低(P<0.05);POCD小鼠接受依替福辛预处理后,海马四氢孕酮含量显著升高(P<0.01);而使用非那司提拮抗后,海马四氢孕酮含量较POCD+EFX组显著降低(P<0.05)。结论依替福辛可显著改善术后认知功能障碍小鼠的认知能力,可与其改善脑内炎性状态及促进甾体类激素四氢孕酮的合成有关。

Objective To investigate the preventive effects of translocation protein 18kDa(TSPO 18kDa)ligand etifoxine(EFX)on postoperative cognitive dysfunction(POCD)in mice,and to explore its action mechanisms.Methods The aged male C57BL/6J mice were randomly divided into four groups:control group,POCD group,POCD+EFX group,POCD+EFX+FIN(finasteride)group,in which finasteride was a blocker of allopregnanolone production.Morris Water Maze(MWM)training was conducted for 4 consecutive days fot all the mice.Before MWM training,etifoxine(50mg/kg)was administered(i.p.)to mice in POCD+EFX group once a day for 3 days,and etifoxine(50mg/kg)and finasteride(50mg/kg)were administered(i.p.)to mice in POCD+EFX+FIN group once a day for 3 days.The partial hepatectomy was performed in POCD group,POCD+EFX group and POCD+EFX+FIN group.MWM probe trials were performed at 3-day and 7-day after surgery,then all the mice were sacrificed,and hippocampal tissues of mice were taken for lab tests.Results The results of probe trial at 3 days after surgery showed that the residence time and swimming distance in target quadrant in POCD group were significantly shorter than those in control group(P<0.01),which in POCD+EFX group were significantly lengthened(P<0.05).After treatment with finasteride antagonist,the swimming distance in target quadrant was shortened again(P<0.05).The hippocampal TSPO levels at 3 days after operation in POCD group were significantly increased,ascompared with those in control group(P<0.05),however,which in POCD+EFX group weresignificantly lower than those in POCD(P<0.01).The expression levels of TNF-α,IL-1βat 3 daysafter operation in POCD group were significantlyhigher than those in control group(P<0.01),andetifoxine pretreatment could obviously decrease theexpression levels of TNF-α,IL-1β.After treatmentwith finasteride antagonist,the levels of L-1βweresignificantly increased(P<0.05),the levels TNF-αlevel were increased,but there were no significant differences(P>0.05).The levels of hippocampal allopregnanolone at 3 days after operation in POCD group were significantly decreased,as compared with those in control group(P<0.05).After etifoxine pretreatment,the levels of hippocampal allopregnanolone in POCD group were significantly increased(P<0.05),moreover,after treatment with finasteride antagonist,the levels of hippocampal allopregnanolone in POCD group were significantly lower than those in POCD+EFX(P<0.05).Conclusion The etifoxine can obviously improve the cognitive dysfunction of mice with POCD,and its action mechanism may be correlated with its effects in improving neuroinflammation and increasing the allopregnanolone synthesis.