Antidepressant effects of Yuanzhi (Polygalae Radix) extract on chronic unpredictable mild stress-induced depression in rats: modulation of the NLRP3 inflammasome and NF-κB pathway

Objective To investigate the antidepressant effects of Yuanzhi(Polygalae Radix;PR)aqueous extract on chronic unpredictable mild stress(CUMS)-induced depression rat models and the underlying mechanisms.Methods A total of 40 male Sprague Dawley(SD)rats were randomly divided into control;model;low dose of PR(PR-L;0.5 g/kg);high dose of PR(PR-H;1 g/kg);and fluoxetine(10 mg/kg)groups;with 8 rats in each group.Except for the rats in control group;those in the other four groups underwent CUMS-induced depression modeling.PR and fluoxetine were administered intragastrically once daily;30 min prior to the CUMS procedure;for 14 consecu-tive days until the behavioral tests were performed.After CUMS modeling;the sucrose prefer-ence test(SPT);open field test(OFT);novelty-suppressed feeding test(NSFT);forced swim test(FST);and tail suspension test(TST)were employed to assess the pharmacological ef-fects of PR on the mitigation of depressive-like behaviors in rat models.Additionally;the en-zyme-linked immunosorbent assay(ELISA)was utilized to quantify the serum levels of tumor necrosis factor(TNF)-α;interleukin(IL)-6;and IL-1βin the rats.Western blot analysis was al-so conducted to evaluate the protein expression levels of nuclear factor kappa-B(NF-κB);in-ducible nitric oxide synthase(iNOS);cyclooxygenase-2(COX-2);nucleotide-binding oligomerization domain(NOD)-like receptor family pyrin domain containing 3(NLRP3);apoptosis-associated speck-like protein containing caspase recruitment domain(ASC);and caspase-1 in the hippocampal tissues of the rats.Immunofluorescence staining was per-formed to observe the morphological changes in ionized calcium-binding adapter molecule 1 positive(Iba-1+)cells in the dentate gyrus(DG)of rats with CUMS-induced depression.Results(i)Treatment with PR-H and fluoxetine resulted in significant enhancements in both the total distance and time the rats moved during tests(P<0.01 and P<0.05;respectively).Post-administration of PR-H and fluoxetine also led to statistically significant increase in su-crose preference among rats(P<0.05).Besides;PR-L;PR-H;and fluoxetine treatment markedly decreased the latency of ingestion(P<0.05;P<0.05;and P<0.01;respectively).As observed from the FST;PR-L;PR-H;and fluoxetine presented antidepressant effects on rats with CUMS-induced depression;leading to the reduction in time of their immobility(P<0.05;P<0.01;and P<0.01;respectively).The results of TST indicated reduced immobility time in rats receiving PR-H and fluoxetine treatment as well(P<0.01).(ii)Rats in model group showed an increase in the levels of Iba-1+microglia in their left and right brains in compari-son with control group(P<0.01).However;such increase was negated post PR treatment(P<0.01).Treatment with PR-L;PR-H;and fluoxetine considerably reduced the levels of inflam-matory factors(TNF-α;IL-1β;and IL-6;P<0.01).In addition;treatment of PR-L and PR-H ef-fectively counteracted the elevated levels of NLRP3;ASC;and caspase-1;and markedly down-regulated the expression levels of phosphorylated p65(p-p65);COX-2;and iNOS in rats’hip-pocampus(P<0.01).Conclusion Collectively;these findings indicate that PR exerts an antidepressant effect on rats with CUMS-induced depression partially through the modulation of the NLRP3 and NF-κB signaling pathways.

The therapeutic mechanism of Shenyuan Gan in lipopolysaccharide-induced neuroinflammation in BV2 microglial cells

Objective To study the therapeutic effects of Shenyuan Gan(参远苷,SYG)on the inflammat-ory response in BV2 microglial cells induced by lipopolysaccharide(LPS).Methods The cytotoxicity of SYG to BV2 microglial cells was evaluated using a Cell Counting Kit-8(CCK-8)assay,and the effect of SYG concentrations on LPS-induced BV2 microglial cells was studied.The morphological changes were observed using an optical microscope.The nitric oxide(NO)concentration in cell culture supernatant was determined using Griess re-agent.The expression of cytokines and inflammatory mediators were also measured by an en-zyme-linked immunosorbent assay(ELISA).Western blot analysis was used to determine the levels of inducible NO synthase(iNOS),nuclear factor-kappa B(NF-κB)p65,alpha inhibitor of NF-κB(IκB-α),phosphorylation-IκB-α(p-IκB-α),NOD-like receptor 3(NLRP3),and cas-pase-1 expression.Moreover,the expression of iNOS,NLRP3,and ionized calcium binding adapter molecule 1(Iba1)was also observed using immunofluorescent staining.Results SYG had a low cytotoxic effect on BV2 microglial cells and could significantly decr-ease LPS-induced morphological changes of BV2 microglial cells(P<0.05).ELISA results showed that SYG significantly inhibited the LPS-induced increase in interleukin(IL)-1βand IL-6 in BV2 microglia cells(P<0.05),and Western blot analysis showed that the phosphoryla-tion levels of iNOS,NF-κB p65,and IκB-αas well as NLRP3 and caspase-1 expression were also significantly decreased,and IκB-αexpression was increased after SYG treatment(P<0.05,compared with the LPS-treated group).The immunofluorescence results were consist-ent with the Western blot results,and Iba1 staining indicated that the cell morphology tended to be resting.These results indicate that SYG has a certain inhibitory effect on LPS-induced inflammation in BV2 microglial cells.Conclusion SYG can inhibit LPS-induced release of inflammatory factors in BV2 microglial cells by affecting the phosphorylation levels of NF-κB p65 and IκB-α.SYG is a valuable candid-ate for treating neuroinflammation-related diseases.

血三七抗氧化活性成分研究

目的研究民间药材血三七的抗氧化活性成分。方法采用硅胶、Sephadex LH-20、半制备HPLC等色谱方法进行分离纯化,通过波谱学方法及与文献对照鉴定化合物的结构;并利用氧自由基吸收能力(ORAC)测定方法评价化合物的体外抗氧化活性。结果分离鉴定了12个化合物,分别为胡萝卜苷(1),槲皮素-3-O-α-D-呋喃阿拉伯糖苷(2),根皮苷(3),没食子酸(4),(2R,3R)-5,7,2',5'-四羟基-黄烷-3-醇(5),儿茶素(6),原儿茶酸甲酯(7),没食子酸甲酯(8),lyoniresinol(9),反式阿魏酸(10),原儿茶酸(11)和绿原酸甲酯(12)。化合物2～7,9～12的抗氧化活性强于抗坏血酸(VitC),化合物8的抗氧化活性较弱。结论所有化合物均为首次从该植物中分离得到,其中2～3,5和12为首次从该属植物中分离得到;化合物2～12均有一定抗氧化活性。

The antidepressive effect of the complex consisting of Radix Pseudostellariae,Radix Pueraria and Herba Epimedii:the involvement of NRSF/NRSE-TPH2 signaling

Depression is a psychological disease with no particularly effective therapy currently available.In the present study,we aimed to examine the antidepressive activity of a pharmaceutical Chinese medicine called TaiZi(TZ)capsule,consisting of total polysaccharides of Radix Pseudostellariae and total flavonoids of both Radix Pueraria and Herba Epimedii.A tail suspension test and forced swimming test were performed to assess the effect of TZ in vivo.A plasmid of TPH2(tryptophan hydroxylase-2)was constructed to determine the exact target of TZ in vitro.In addition,mRNA expression was detected using a real-time PCR assay,and the protein expression was investigated using a Western blotting analysis.The results showed that TZ had an anti-depression effect in mouse and rat models with increased serotonin in the brain,and in the upregulation of mRNA and protein expression of TPH2 in the brain simultaneously by inhibition of NRSF(neuron restrictive silencer factor)expression because NRSF could bind to NRSE(neuron restrictive silencer element)to repress TPH2 transcription during the depression conditions.Icariin could bind to NRSE directly and block NRSF protein toward to NRSE for TPH2 inhibition.Therefore,we concluded that TZ had potential antidepressive effects because it could ameliorat the depression-like behavior in the animals,and the underlying mechanism of the effect was involved in NRSF/NRSE-TPH2 signaling.Icariin was identified as the active component of TZ.This study provided a new perspective for the development of antidepression drugs(Chinese medicines)based on NRSF/NRSE-TPH2 signaling.

Urinary metabolomics analysis of the anti-depressive effects of Hemerocallis citrina extracts in a simulated microgravity-induced rat model of depression

We investigated the antidepressant-like activity of Hemerocallis citrine Baroni extract(HCE)in a simulated microgravity(SMG)-induced rat model of depression using a metabolomics method.A rat model,generated via 14 d of SMG induction,was validated from the reduced sucrose preference and the enhanced immobility time in the forced swimming test.HCE and paroxetine reversed certain metabolite profiles.Anti-depressant effects of HCE might involve the regulation of several metabolic pathways,such as phenylalanine,glutamic acid,and tryptophan metabolism and changes in energy metabolism.5-Hydroxytryptophan,hippuric acid,phenylacetylglycine,citric acid,3-hydroxykynurenine,cyclic AMP,and L-DOPA profiles were altered upon HCE and paroxetine administration.Furthermore,glutamic acid was only regulated in the HCE group,while xanthurenic acid and deoxyuridine were reversed in the positive group,suggesting differences in the mechanisms between the positive drugs and HCE in improving glutamic acid metabolism.This study provided a theoretical foundation for the application of HCE in depression therapy.