跑台运动联合黑枸多糖改善模型小鼠的抑郁症样行为

Improvement of depression-like behaviors by treadmill exercise combined with black lycium polysaccharide in mice

目的探讨7周跑台运动及黑枸多糖灌服对小鼠抑郁样行为的影响和海马α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体(AMPAR)相关通路的改变。方法50只雄性昆明(KM)小鼠,随机分成空白组(K,n=10)和抑郁症组(CUMS,n=40),抑郁症组随机采用13种慢性不可预见温和应激成功构建小鼠模型,构建成功后分为模型组(M)、跑台运动组(E)、黑枸多糖组(L)和跑台运动联合黑枸多糖组(EL),每组10只。实验方法有行为学评估,海马组织5羟色胺(5-HT)、脑源性神经营养因子(BDNF)和多巴胺(DA)含量检测,血清S100钙结合蛋白B(S100B)和神经元特异性烯醇化酶(NSE)含量检测,脑组织Nissl染色,海马组织AMPAR、谷氨酸受体1(GluR1)和钙调素依赖蛋白激酶Ⅱα(CaMKⅡα)蛋白含量测定,mRNA表达谱分析后采用Western blotting和Real-time PCR检验AMPAR、GluR1和CaMKⅡα表达水平。结果1.模型小鼠抑郁样行为表现明显,海马组织5-HT、BDNF和DA含量下降,而S100B和NSE含量上升(P<0.01),前额叶皮层神经元缺失,尼氏体固缩或空泡状,显示神经元损伤严重。2.与M组比较,E、L和EL组小鼠抑郁样行为明显改善,海马组织5-HT、BDNF和DA含量上升,血清S100B和NSE含量降低(P<0.01或P<0.05)。行为结果与S100B、NSE含量的统计学分析显示,跑台运动和黑枸多糖干预具有协同效应。3.与M组比较,E、L和EL组小鼠海马组织AMPAR、GluR1和CaMKⅡα蛋白含量上升(P<0.01),且跑台运动和黑枸多糖具协同效应;基于Illumina高通量测序发现,AMPAR突触后膜紧密相关的长时程增强、长时程抑制信号通路内有49个上调基因和18个下调基因,涉及突触可塑性、学习记忆和神经元损伤修复等相关通路。Real-time PCR结果显示,E、L和EL组AMPAR、GluR1和CaMKⅡα基因的mRNA水平显著增加,且跑台运动和黑枸多糖具有协同效应。结论7周跑台运动和黑枸多糖灌服可改善小鼠抑郁样症状,可能是通过影响CaMKⅡα的磷酸化进而调控AMPAR活性,促进神经元损伤修复和改善突触可塑性及功能实现的。

Objective To study the effects of 7-week treadmill exercise combined with black lycium polysaccharide on depression-like behaviors and explore the alterations of hippocampalα-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor(AMPAR)associated pathways in mice.Methods Fifty male Kunming(KM)mice were randomly divided into blank group(K,n=10)and chronic unpredictable mild stress group(CUMS,n=40).For the CUMS group,13-random chronic unpredictable mild stress method were used to induce depression-like behaviors.After successful modeling,the mice were further divided into model group(M),treadmill exercise group(E),black lycium polysaccharide group(L),and treadmill exercise combined with black lycium polysaccharide group(EL);each group contained 10 mice,and intervention lasted for 7 weeks.The behavioral assessment was performed;the contents of 5-hydroxytryptamine(5-HT),brain-derived neurotrophic factor(BDNF)and dopamine(DA)in hippocampal tissue,and the levels of S100 calcium binding protein B(S100B)and neuron-specific enolase(NSE)in serum were detected;Nissl staining was carried out to observe the structure of brain tissue;AMPAR,glutamate receptor 1(GluR1)and calcium/calmodulin-dependent protein kinase-α(CaMKⅡα)proteins in hippocampal tissue were detected;Real-time PCR was used to verify the expression of hippocampal AMPAR,GluR1 and CaMKⅡαmRNA obtained by mRNA sequencing.Results 1.Compared with the blank group,the mice in CUMS group had obvious depression-like behaviors(P<0.01);the contents of 5-HT,BDNF and DA in hippocampal tissue decreased significantly,while those of S10OB and NSE increased(P<0.01);Neurons in the prefrontal cortex were absent,the Nissl nacleus was condensed,and the arrangement was irregular and sparse.2.Compared with the model group,the behavioral assessment of the mice in the E,L and EL groups were significantly improved,reflecting that the contents of 5-HT,BDNF and DA in hippocampal tissue increased,and the serous S100B and NSE levels decreased(P<0.01 or P<0.05);for sucrose preference test(SPT)and forced swimming test(FST),S10OB and NSE content result showed that treadmill exercise and black lycium polysaccharide intervention had a synergistic effect on behavioral improvement.3.Compared with the model group,the contents of AMPAR,GluR1,and CaMKⅡαproteins in hippocampal tissue of mice in the E,L and EL groups increased(P<0.O1),and there was a synergistic effect between treadmill exercise and black lycium polysaccharides;the Illumina high-throughput sequencing data showed that there were 49 up-regulated genes and 18 down-regulated genes involving learning and memory,and neuronal damage repair,etc.which were closely related to postsynaptic membrane location of AMPA receptors and synaptic long-term potentiation and long-term depression,The increased transcriptions of AMPAR,GluR1 and CaMK Ⅱαrevealed by the sequencing were verified by Real-time PCR data,and there was a synergistic effect between the treatments of treadmill exercise and black lycium polysaccharides.Conclusion Seven weeks of treadmill exercise and administration of black lycium polysaccharides can improve depression-like behaviors in mice,possibly by affecting the phosphorylation of CaMK Ⅱαto regulate AMPAR activity,promote neuronal damage repair and improve synaptic plasticity and function.