甘麦养心汤对抑郁症大鼠海马谷氨酸系统表达的影响

Effects of Ganmai Yangxin Decoction on the Expression Glutamate System in Hippocampus of Depression Rats

目的观察甘麦养心汤对抑郁症大鼠海马谷氨酸系统表达的影响,探讨其治疗抑郁症的作用机制。方法40只SPF级SD大鼠随机分为空白组和造模组,采用慢性轻度不可预知性应激法建立抑郁症模型,将造模成功大鼠随机分为模型组、氟西汀组和甘麦养心汤组,每组8只。甘麦养心汤组予甘麦养心汤水煎液7.67g/kg灌胃,氟西汀组予氟西汀溶液10mg/kg灌胃,空白组和模型组予10mL/kg生理盐水灌胃,连续4周,给药同时继续造模。蔗糖偏好实验和强迫游泳实验评估大鼠抑郁状态,ELISA检测大鼠海马组织谷氨酸含量,尼氏染色观察海马CA3区神经元形态,免疫组化染色检测海马CA3区胶质纤维酸性蛋白(GFAP)蛋白表达,Western blot检测海马组织兴奋性氨基酸转运体(EAAT)1、EAAT2、EAAT3、囊泡谷氨酸转运体(VGLUT)1、VGLUT2蛋白表达,RT-PCR检测海马组织EAAT1、EAAT2、EAAT3mRNA表达。结果与空白组比较,模型组大鼠体质量减轻(P<0.01),蔗糖偏好率降低、强迫游泳不动时间增加(P<0.01),海马组织谷氨酸含量升高(P<0.01),海马CA3区神经元数量减少、排列不整齐、结构改变,尼氏体数量减少,海马CA3区GFAP阳性表达降低(P<0.01),海马组织EAAT1、EAAT2、EAAT3蛋白和mRNA及VGLUT1蛋白表达降低(P<0.01),VGLUT2蛋白表达升高(P<0.05);与模型组比较,甘麦养心汤组和氟西汀组大鼠体质量增加(P<0.05),蔗糖偏好率升高、强迫游泳不动时间缩短(P<0.01),海马组织谷氨酸含量降低(P<0.01),海马CA3区神经元数量增加、结构改善,尼氏体较多,海马CA3区GFAP阳性表达升高(P<0.01),海马组织EAAT1、EAAT2、EAAT3蛋白和mRNA及VGLUT1蛋白表达升高(P<0.05,P<0.01)。结论甘麦养心汤可改善大鼠抑郁样行为,其作用机制与上调海马组织谷氨酸转运体表达、增加星形胶质细胞数量、降低谷氨酸含量有关。

Objective To observe the effects of Ganmai Yangxin Decoction on the expression glutamate system in hippocampus of rats with depression;To discuss its mechanism for the treatment of depression.Methods Totally 40 SPF grade SD rats were randomly divided into blank group and modeling group,chronic unpredictable mild stress method was used to establish a depression model.Successfully modeling rats were randomly divided into model group,fluoxetine group and Ganmai Yangxin Decoction group,with 8 rats in each group.The rats in Ganmai Yangxin Decoction group were gavaged with 7.67 g/kg decoction,the fluoxetine group was gavaged with 10 mg/kg fluoxetine,and the blank group and model group were gavaged with 10 mL/kg normal saline,for 4 weeks.and modeling continued while administering the medication.Sucrose preference experiments and forced swimming experiments were used to evaluate the depression status of rats,ELISA was used to detect glutamate content in hippocampal tissue,Nissl staining was used to observe the morphology of neurons in hippocampal CA3 region,immunohistochemical staining was used to detect the expression of GFAP protein in hippocampal CA3 region,Western blot was used to detect the expressions of EAAT1,EAAT2,EAAT3,VGLUT1 and VGLUT2 protein in hippocampal tissue,RT-PCR was used to detect the mRNA expressions of EAAT1,EAAT2 and EAAT3 in hippocampal tissue.Results Compared with the blank group,the body mass of the model group rats decreased(P<0.01),sucrose preference rate decreased,forced swimming immobility time increased(P<0.01),and glutamate content in hippocampal tissue increased(P<0.01),the number of neurons in hippocampal CA3 region decreased,with irregular arrangement and structure changed,the number of Nissl bodies decreased,and the positive expression of GFAP in hippocampal CA3 region decreased(P<0.01),the expressions of EAAT1,EAAT2,EAAT3 protein and mRNA,and VGLUT1 protein in hippocampal tissue decreased(P<0.01),while the expression of VGLUT2 protein increased(P<0.05).Compared with the model group,the Ganmai Yangxin Decoction group and the fluoxetine group showed an increase in body mass(P<0.05),an increase in sucrose preference rate,and a reduction in forced swimming immobility time(P<0.01),and the glutamate content in hippocampal tissue decreased(P<0.01),the number of neurons in the hippocampal CA3 region increased,the structure improved,and there were more Nissl bodies,the positive expression of GFAP in hippocampal CA3 region increased(P<0.01),the expressions of EAAT1,EAAT2,EAAT3 protein and mRNA,and VGLUT1 protein in hippocampal tissue increased(P<0.05,P<0.01).Conclusion Ganmai Yangxin Decoction can improve depression-like behavior in rats,and its mechanism of action is related to up-regulating the expression of glutamate transporters,increasing the number of astrocytes,and reducing glutamate content in hippocampus.