艾司氯胺酮对慢性可变应激小鼠抑郁样行为及前额叶皮质鞘脂水平的影响

Effects of esketamine on depressive-like behavior and prefrontal cortex sphingolipid levels in chronic variable stress mice

目的 探讨艾司氯胺酮对慢性可变应激(CVS)小鼠抑郁样行为及前额叶皮质(PFC)鞘脂水平的影响。方法 将31只C57小鼠随机分为对照组(n=10)、模型+生理盐水组(n=10)和模型+艾司氯胺酮治疗组(n=11)。模型+生理盐水组和模型+艾司氯胺酮治疗组小鼠均接受21 d CVS造模。造模结束后,两组小鼠分别接受10μL/g生理盐水、10 mg/kg艾司氯胺酮腹腔注射。通过旷场实验、高架十字迷宫测试、悬尾实验及强迫游泳实验测试小鼠的抑郁样行为;随后处死小鼠,分离出PFC,通过高效液相色谱-质谱联用技术检测PFC鞘脂水平及组成小分子差异,采用LipidSearch 4.1和SIMCA-P 14.1软件分析脂质相对含量。使用SPSS 26.0进行数据处理,多组间差异采用单因素方差分析,两组间差异进行Tukey检验。结果 (1)CVS模型可以诱导稳定的小鼠抑郁样行为,3组小鼠旷场测试、高架十字迷宫测试、悬尾实验及强迫游泳测试的结果均有统计学差异;单次腹腔注射艾司氯胺酮可以逆转小鼠抑郁样行为,并且改变部分鞘脂水平及其组成小分子。(2) 3组小鼠鞘脂总体水平的差异有统计学意义(F_(2,28)=22.92,P<0.01),鞘脂的三个亚类鞘磷脂(F_(2,28)=15.76,P<0.01)、脑苷脂(F_(2,28)=21.56,P<0.01)、神经节苷脂(F_(2,28)=4.056,P<0.05)之间的差异均有统计学意义。进一步对其小分子组成进行分析发现,CVS造模之后植物鞘氨醇(phSM)、GM3均明显下降,艾司氯胺酮治疗增加了上述脂质小分子的水平(均P<0.05);与对照组相比,模型+生理盐水组磷酸肌酸(CerP)、硫苷脂水平下降,而艾司氯胺酮治疗并未影响上述脂质小分子的水平。(3)PFC鞘脂水平与行为学结果之间存在一定的相关性。CVS小鼠PFC总体鞘脂水平与旷场中心停留时间存在相关性(Pearson r=0.378 1,P<0.05),小分子phSM与旷场中心停留时间存在相关性(P<0.05);CVS小鼠PFC脑苷脂的小分子神经酰胺、CerP和CerG3水平与悬尾不动时间存在相关性(均P<0.05)。结论 艾司氯胺酮治疗可以改善CVS小鼠抑郁样行为,其作用可能与小鼠PFC鞘脂相对含量变化,尤其是鞘磷脂水平相关。

Objective To investigate the effects of esketamine on depressive-like behavior and prefrontal cortex(PFC)sphingolipid levels in chronic various stress(CVS)mice.Methods Thirty-one C57 mice were randomly divided into control group(n=10),model+saline group(n=10)and model+esketamine treatment group(n=11).Mice in model+saline group and model+esketamine treatment group received CVS modeling for 21 d.After modeling,mice in the two groups received intraperitoneal injection of 10μL/g normal saline and 10 mg/kg esketamine,respectively.The depressive-like behavior of mice was tested by open field test,elevated plus maze test,tail suspension test and forced swim test.Then mice were sacrificed,and the PFC was isolated.The PFC sphingolipid level and composition of small molecules were detected by high-performance liquid chromatography-mass spectrometry.LipidSearch 4.1 and SIMCA-P 14.1 were used to analyze the relative lipid content.SPSS 26.0 was used for data processing,one-way ANOVA was used for differences among multiple groups,and Tukey test was used for differences between two groups.Results①CVS model could induce stable depression-like behavior in mice,and the results of open field test,elevated plus maze test,tail suspension test and forced swim test were statistically different in the three groups of mice.A single intraperitoneal injection of esketamine reversed depressive-like behavior in mice and altered partial sphingolipid levels and their constituent small molecules.②There was a statistically significant difference in the overall level of sphingolipids in the three groups(F_(2,28)=22.92,P<0.01),and the differences among the three subclasses of sphingolipids:sphingomyelin(F_(2,28)=15.76,P<0.01),cerebrosides(F_(2,28)=21.56,P<0.01)and gangliosides(F_(2,28)=4.056,P<0.05)were also statistically significant.Further analysis of the composition of small molecules showed that phytosphingosine(phSM)and GM3 decreased significantly after CVS modeling,and esketamine treatment increased the levels of the above small lipid molecules(all P<0.05).Compared with the control group,the levels of ceramides phosphate(CerP)and sulfatide decreased in the model+saline group,but esketamine treatment did not affect the levels of the above small lipid molecules.③There was a certain correlation between PFC sphingolipid levels and behavioral results.The PFC sphingomyelin levels of CVS mice were correlated with residence time in the central area in open field test(Pearson r=0.3781,P<0.05),and small molecule phSM was also correlated with residence time in the central area in open field test(P<0.05).Small molecules ceramide,CerP and CerG3 levels of PFC cerebrosides in CVS mice were correlated with immobility time of tail suspension in tail suspension test(all P<0.05).Conclusion Esketamine treatment can improve depression-like behavior in CVS mice,which may be related to the changes in the relative content and composition of PFC sphingolipids in mice,especially the sphingomyelin level.