槲皮素通过Rac1/LIMK1/cofilin信号通路治疗抑郁症的机制研究

The mechanism of quercetin in the treatment of depression through Rac1/LIMK1/cofilin signaling pathway

目的 探讨槲皮素(Que)对慢性不可预测轻度应激(CUMS)小鼠抑郁行为的影响和可能的作用机制。方法 将60只C57BL/6J小鼠随机分为对照组(Control组)、模型组(Model组)、氟西汀组(Positive组)、低浓度Que组(L-Que组)、高浓度Que组(H-Que组)。构建CUMS小鼠抑郁模型,给予不同浓度的槲皮素(20 mg·kg、40 mg·kg)灌胃治疗,氟西汀(10 mg·kg)作为阳性对照。通过体质量测量、糖水偏好实验、悬尾实验、强迫游泳行为学实验检测小鼠抑郁程度;尼氏染色检测小鼠海马神经元形态和数量;高尔基染色检测海马神经元树突棘形态;实时荧光定量PCR(RT-qPCR)检测小鼠海马中脑源性神经营养因子(BDNF)、酪氨酸激酶受体B (TrkB)、突触素(SYP)及突触后致密物-95 (PSD-95)mRNA表达;Western blotting检测小鼠海马中BDNF、TrkB、SYP、PSD-95、Ras相关的C3肉毒素底物1(Rac1)、LIM激酶1 (LIMK1)、p-LIMK1、丝切蛋白(cofilin)、p-cofilin蛋白水平。结果 与Control组比较,Model组小鼠体质量、糖水偏好百分比显著降低,悬尾和强迫游泳的不动时间显著增加(P<0.05);Model组小鼠海马神经元数量明显减少,尼氏小体部分消失或溶解,海马区树突棘密度显著减少,BDNF、TrkB、SYP、PSD-95 mRNA水平以及BDNF、TrkB、SYP、PSD-95、Rac1、p-LIMK1、p-cofilin蛋白水平均显著降低(P<0.05)。L-Que组和H-Que组显著改善了小鼠的抑郁样行为(P<0.05);与Model组比较,L-Que组和H-Que组小鼠海马神经元数量明显增多,树突棘密度升高,BDNF、TrkB、SYP、PSD-95 mRNA水平以及BDNF、TrkB、SYP、PSD-95、Rac1、p-LIMK、p-cofilin蛋白水平均显著升高(P<0.05)。结论 Que通过激活Rac1/LIMK1/cofilin通路增强突触可塑性从而改善小鼠抑郁样行为。

Objective This study explored the effect of quercetin on the depressive behavior of mice with chronic unpredictable mild stress(CUMS) and its possible mechanism.Methods Sixty C57 BL/6 J mice were randomly divided into control group,model group,positive group,low-concentration quercetin group(L-Que group),high-concentration quercetin group(H-Que group).CUMS mouse depression model was constructed,and different concentrations of quercetin(20 mg·kg,40 mg·kg) were given intragastrically,and fluoxetine(10 mg·kg)was used as a positive control.The depression degree of mice was measured by weight measurement of sugar water preference test,tail suspension test,forced swimming behavior test.Morphology and number of hippocampal neurons were detected by Nissl staining.Morphology of dendritic spines in hippocampal neurons was detected by Golgi staining.Real-time quantitative fluorescence PCR(RT-qPCR) was used to detect the expression of brainderived neurotrophic factor(BDNF),Tyrosine kinase receptor B(TrkB),synaptophysin(SYP),Postsynaptic density-95(PSD-95) mRNA in the hippocampus of mice.Western blotting was used to detect the protein levels of BDNF,TrkB,SYP,PSD-95,Ras-associated C3 botulinum toxin substrate 1(Rac1),LIM kinase 1(LIMK1),p-LIMK1,cofilin,and p-cofilin in the hippocampus of mice.Results Compared with the control group,the weight and percentage of preference for sugar and water in the model group were significantly reduced,and the immobility time of tail suspension and forced swimming was significantly increased(P<0.05).The number of hippocampal neurons in the model group was significantly reduced,Nissl bodies partially disappeared or dissolved,and the dendritic spine density in the hippocampus was significantly reduced.The levels of BDNF,TrkB,SYP,PSD-95 mRNA,and BDNF,TrkB,SYP,PSD-95,Rac1,p-LIMK1,and the protein level of p-cofilin decreased significantly(P<0.05).The L-Que group and H-Que group significantly improved the depression-like behavior of the mice(P<0.05);compared with the Model group,the number of hippocampal neurons in the L-Que group and the H-Que group increased significantly,and the dendritic spines density increased,BDNF,TrkB,SYP,PSD-95 mRNA levels and PSD-95,Rac1,LIMK,and p-cofilin protein levels were significantly increased(P<0.05).Conclusion Quercetin enhances synaptic plasticity by activating the Rac1/LIMK1/cofilin pathway to improve depression-like behavior in mice.