慢性温和不可预知应激抑郁模型大鼠脑组织1H-NMR代谢组学研究

目的 采用高分辨核磁共振¹H谱（¹H-NMR）代谢组学技术研究慢性温和不可预知应激（CUMS）抑郁大鼠脑组织中代谢物及代谢通路的变化,探讨抑郁症的发病机制。方法 12只雄性SD大鼠随机分为模型组和对照组,采用CUMS对模型组大鼠进行为期4周的造模,进行称体质量、旷场实验和糖水偏爱实验验证模型是否成功,造模结束后收集大鼠脑组织。采用两相提取法（甲醇/氯仿/水）对脑组织进行提取,得到水溶性和脂溶性代谢物。应用¹H-NMR技术结合多元统计和代谢通路分析筛选出与抑郁相关的脑内差异代谢物,并构建其代谢通路。结果 行为学数据显示,与对照组比较,模型组大鼠的体质量、糖水偏爱率、旷场的穿格数和直立次数均显著降低（P<0.05）,显示了抑郁状态。在大鼠脑组织的¹H-NMR图谱中共指认出35种内源性代谢产物。脑组织中水溶性和脂溶性代谢物主成分分析（PCA）均显示模型组与对照组分开,与行为学结果一致,表明造模成功;OPLS-DA分析找到9个水溶性差异代谢物和6个脂溶性差异代谢物。就水溶性代谢物而言,与对照组比较,模型组中肌酐、谷氨酰胺、牛磺酸和γ-氨基丁酸含量显著增加（P<0.05、0.01、0.001）,丙二醇、谷氨酸、亮氨酸、缬氨酸和赖氨酸含量显著降低（P<0.05、0.01、0.001）。就脂溶性代谢物而言,与对照组比较,模型组-（CH₂） n和-N （Me₃）₃含量显著升高（P<0.05、0.001）,胆固醇的C18/19甲基、R-CH₃、CH₂OPO₂-、-CH=CH-含量显著降低（P<0.05、0.01、0.001）。与对照组比较,CUMS造模后5条代谢通路发生显著变化：缬氨酸、亮氨酸和异亮氨酸生物合成,牛磺酸和亚硫磺酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,糖降解和糖异生通路和丙酮酸代谢。结论 运用¹H-NMR代谢组学技术结合多元统计分析和代谢通路分析,阐明抑郁症的发病机制与能量代谢、氨基酸代谢和神经递质合成等相关。

1H-NMR metabonomic study on brain tissues of chronic unpredicted mild stress model of depression in rats

Objective To study the metabolic changes of brain tissues of chronic unpredictable mild stress (CUMS) rats by 1H-NMR and obtain the potential biomarkers of CUMS rats to investigate the pathogenesis of depression.Methods A total of 12 male Sprague-Dawley (SD) rats were randomly divided into two groups,namely the control and model groups.The CUMS procedure was conducted for four weeks.The weight test,open field experiment and sugar preference experiment were conducted to verify the success of the model.The brain tissues of rats were collected at the end of the procedure.The endogenous metabolites in brain tissues were extracted by MeOH/CHCl₃/H₂O.And the hydrosoluble and liposoluble metabolites were analyzed by ¹H-NMR with different sequences.The differences of metabolites between control group and CUMS group were analyzed by multivariate statistical analysis.The metabolic pathways were constructed.Results Body weight,sucrose preference,ambulation number and rearing number in open-field test of the CUMS rats decreased significantly after 28d procedure as compared with those of the control groups (P<0.05).Also,in the scores plot of principle component analysis (PCA) on brain metabolites,the CUMS-depressed rats were significantly separated with the control rats,suggesting the CUMS model has been built successfully.Thirty-five metabolites were identified in the ¹H-NMR spectra of brain tissues.Nine hydrosoluble differential metabolites and six fat-soluble differential metabolites were found by OPLS-DA analysis.Taking hydrosoluble metabolites into account,the content of creatinine,glutamine,taurine and gamma-aminobutyric acid in the CUMS rats significantly increased (P<0.05),while propanediol,glutamic acid,leucine,valine and lysine were significantly decreased in CUMS model group as compared with the control group (P<0.05,0.01,and 0.001).As far as fat-soluble metabolites are concerned,compared with the control group,the content of-(CH₂) n and-N (Me₃)₃ in the model group increased significantly (P<0.05,0.001),while the content of C18/19 methyl,R-CH₃,CH₂OPO₂-,and-CH=CH-in cholesterol decreased significantly (P<0.05,0.01,0.001).Compared with the control group,there were significant changes in five metabolic pathways:valine,leucine and isoleucine biosynthesis,taurine and sulfite metabolism,alanine,aspartic acid and glutamic acid metabolism,sugar degradation and gluconeogenesis pathway and pyruvate metabolism.Conclusion Using ¹H-NMR metabonomics combined with multivariate statistical analysis and metabolic pathway analysis,the pathogenesis of depression is related to energy metabolism,amino acid metabolism and neurotransmitter synthesis.