Single-dose methamphetamine administration impairs ORM retrieval in mice via excessive DA-mediated inhibition of PrLGlu activity.

Methamphetamine (METH), an abused psychostimulant, impairs cognition through prolonged or even single-dose exposure, but animal experiments have shown contradictory effects on memory deficits. In this study we investigated the effects and underlying mechanisms of single-dose METH administration on the retrieval of object recognition memory (ORM) in mice. We showed that single-dose METH administration (2 mg/kg, i.p.) significantly impaired ORM retrieval in mice. Fiber photometry recording in METH-treated mice revealed that the activity of prelimbic cortex glutamatergic neurons (PrLGlu) was significantly reduced during ORM retrieval. Chemogenetic activation of PrLGlu or glutamatergic projections from ventral CA1 to PrL (vCA1Glu-PrL) rescued ORM retrieval impairment. Fiber photometry recording revealed that dopamine (DA) levels in PrL of METH-treated mice were significantly increased, and micro-infusion of the D2 receptor (D2R) antagonist sulpiride (0.25 µg/side) into PrL rescued ORM retrieval impairment. Whole-cell recordings in brain slices containing the PrL revealed that PrLGlu intrinsic excitability and basal glutamatergic synaptic transmission were significantly reduced in METH-treated mice, and the decrease in intrinsic excitability was reversed by micro-infusion of Sulpiride into PrL in METH-treated mice. Thus, the impaired ORM retrieval caused by single-dose METH administration may be attributed to reduced PrLGlu activity, possibly due to excessive DA activity on D2R. Selective activation of PrLGlu or vCA1Glu-PrL may serve as a potential therapeutic strategy for METH-induced cognitive dysfunction.

Recyclable and reusable ionic liquid-supported azo precursors in Mitsunobu reactions.

A new type of azo precursor, ionic liquid-supported hydrazidecarboxylate, was synthesized and applied in Mitsunobu reactions. The developed reagent is recyclable during the reaction and reusable after recovery by the ionic liquids. The ionic liquid-based azo precursor in conjugation with PhI(OAc)2 has been proved to be useful in the formation of carbon-oxygen, carbon-nitrogen, and carbon-sulfur bonds.

Seed oil of Brucea javanica induces apoptosis through the PI3K/Akt signaling pathway in acute lymphocytic leukemia Jurkat cells.

Brucea javanica oil emulsion (BJOE) has been used to treat tumor in China for more than 40 years. However, its components and effectiveness in the treatment of acute lymphocytic leukemia (ALL) and its mechanism of anti-cancer activity remain unknown. In the current study, high-performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) was used to analyze the components of BJOE. Then, the anti-leukemia effects of BJOE were examined both in vitro and in vivo using ALL Jurkat cells and the p388 mouse leukemia transplant model, respectively. The primary ALL leukemia cells were also used to confirm the anti-leukemia effects of BJOE. The apoptotic-related results indicated that BJOE induced apoptosis in Jurkat cells and were suggestive of intrinsic apoptotic induction. Moreover, BJOE inhibited Akt (protein kinase B) activation and upregulated its downstream targets p53 and FoxO1 (forkhead box gene, group O-1) to initiate apoptosis. The activation of GSK3ß was also involved. Our findings demonstrate that BJOE has anti-leukemia effects on ALL cells and can induce apoptosis in Jurkat cells through the phosphoinositide3-kinase (PI3K) /Akt signaling pathway.

Pseudoginsenoside-F11 attenuates cognitive dysfunction and tau phosphorylation in sporadic Alzheimer's disease rat model.

We previously reported that pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, significantly ameliorated Alzheimer's disease (AD)-associated cognitive defects in APP/PS1 and SAMP8 mice by inhibiting Aß aggregation and tau hyperphosphorylation, suggesting a potential therapeutic effect of PF11 in the treatment of AD. In the present study we further evaluated the therapeutic effects of PF11 on relieving cognitive impairment in a rat model of sporadic AD (SAD). SAD was induced in rats by bilateral icv infusion of streptozotocin (STZ, 3 mg/kg). The rats were treated with PF11 (2, 4, 8 mg·kg-1·d-1, ig) or a positive control drug donepezil (5 mg·kg-1·d-1, ig) for 4 weeks. Their cognitive function was assessed in the nest building, Y-maze, and Morris water maze tests. We showed that STZ icv infusion significantly affected the cognitive function, tau phosphorylation, and insulin signaling pathway in the hippocampus. Furthermore, STZ icv infusion resulted in significant upregulation of the calpain I/cyclin-dependent protein kinase 5 (CDK5) signaling pathway in the hippocampus. Oral administration of PF11 dose-dependently ameliorated STZ-induced learning and memory defects. In addition, PF11 treatment markedly reduced the neuronal loss, protected the synapse structure, and modulated STZ-induced expression of tau phosphorylation by regulating the insulin signaling pathway and calpain I/CDK5 signaling pathway in the hippocampus. Donepezil treatment exerted similar beneficial effects in STZ-infused rats as the high dose of PF11 did. This study highlights the excellent therapeutic potential of PF11 in managing AD.

Oxytocin inhibits methamphetamine-associated learning and memory alterations by regulating DNA methylation at the Synaptophysin promoter.

Methamphetamine (METH) causes memory changes, but the underlying mechanisms are poorly understood. Epigenetic mechanisms, including DNA methylation, can potentially cause synaptic changes in the brain. Oxytocin (OT) plays a central role in learning and memory, but little is known of the impact of OT on METH-associated memory changes. Here, we explored the role of OT in METH-induced epigenetic alterations that underlie spatial and cognitive memory changes. METH (2.0 mg/kg, i.p.) was administered to male C57BL/6 mice once every other day for 8 days. OT (2.5 µg, i.c.v.) or aCSF was given prior to METH. Spatial and cognitive memory were assessed. In Hip and PFC, synaptic structures and proteins were examined, levels of DNA methyltransferases (DNMTs) and methyl CpG binding protein 2 (MECP2) were determined, and the DNA methylation status at the Synaptophysin (Syn) promoter was assessed. METH enhanced spatial memory, decreased synapse length, downregulated DNMT1, DNMT3A, DNMT3B, and MECP2, and induced DNA hypomethylation at the Syn promoter in Hip. In contrast, METH reduced cognitive memory, increased synapse thickness, upregulated DNMT1, DNMT3A, and MECP2, and induced DNA hypermethylation at the Syn promoter in PFC. OT pretreatment specifically ameliorated METH-induced learning and memory alterations, normalized synapse structures, and regulated DNMTs and MECP2 to reverse the DNA methylation status changes at the Syn promoter in Hip and PFC. DNA methylation is an important gene regulatory mechanism underlying METH-induced learning and memory alterations. OT can potentially be used to specifically manipulate METH-related memory changes.

Population pharmacokinetics of cyclosporine in Chinese children receiving hematopoietic stem cell transplantation.

Cyclosporine (CsA) is characterized by a narrow therapeutic window and high interindividual pharmacokinetic variability, particularly in juvenile patients. The aims of this study were to build a population pharmacokinetic model of CsA in Chinese children with hematopathy who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to identify covariates affecting CsA pharmacokinetics. A total of 86 Chinese children aged 8.4 ± 3.8 years (range 1.1-16.8 years) who received allo-HSCT were enrolled. Whole blood samples were collected before allo-HSCT. Genotyping was performed using an Agena MassARRAY system. A total of 1010 trough plasma concentration values of CsA and clinical data were collected. The population pharmacokinetic model of CsA was constructed using nonlinear mixed-effects modeling (NONMEM) software. The stability and performance of the final model were validated using bootstrapping and normalized prediction distribution errors. We showed that a one-compartment model with first-order elimination adequately described the pharmacokinetics of CsA. The typical values for clearance (CL) and volume of distribution (V) were 42.3 L/h and 3100 L, respectively. Body weight, postoperative days, CYP3A4*1 G genotype, estimated glomerular filtration rate and coadministration of triazole antifungal drugs were identified as significant covariates for CL. Weight and postoperative days were significant covariates for the V of CsA. Our model can be adopted to optimize the CsA dosing regimen for Chinese children with hematopathy receiving allo-HSCT.

Inhibition of PDE5 attenuates streptozotocin-induced neuroinflammation and tau hyperphosphorylation in a streptozotocin-treated rat model.

Intracerebroventricular (icv) streptozotocin (STZ) injection decreases cerebral insulin signal pathway function and produces multiple effects that resemble the molecular, pathological, and behavioural features of Sporadic Alzheimer's disease (SAD). We previously reported that yonkenafil (yonk), the analogue of sildenafil and a novel PDE5 inhibitor exerts an anti-amyloidogenesis effect by regulating the Aß level and inhibiting the expression of ß-amyloid precursor protein in the APP/PS1 transgenic mice model. In this study, the effects of yonk on cognitive behaviors as well as the pathological features in streptozotocin-induced SAD rat model were investigated. The results demonstrated that administration of yonk at doses of 3 and 10 mg/kg for three weeks significantly improved cognitive deficits, attenuated STZ-induced neuronal death, inhibited the over-activation of microglia and astrocytes and the levels of pro-inflammatory markers, as well as decreased PDE5 protein expression in the hippocampus. Furthermore, yonk (3 mg/kg) notably prevented changes in tau hyperphosphorylation, decreased IRS-1and JNK phosphorylation and increased the GSK3ß (ser9) phosphorylation induced by STZ. In summary, these data suggested that yonk significantly reversed STZ-induced memory deficits by inhibiting the over-activation of microglia and astrocytes, as well as ameliorated the levels of pro-inflammatory makers and tau hyperphosphorylation through regulating GSK3ß signalling pathway.

Loss of Tumor Suppressor Gene Function in Human Cancer: An Overview.

Cancer is a disease caused by the accumulation of genetic and epigenetic changes in two types of genes: tumor suppressor genes (TSGs) and proto-oncogenes. Extensive research has been conducted over the last few decades to elucidate the role of TSGs in cancer development. In cancer, loss of TSG function occurs via the deletion or inactivation of two alleles, according to Knudson's two-hit model hypothesis. It has become clear that mutations in TSGs are recessive at the level of an individual cell; therefore, a single mutation in a TSG is not sufficient to cause carcinogenesis. However, many studies have identified candidate TSGs that do not conform with this standard definition, including genes inactivated by epigenetic silencing rather than by deletion. In addition, proteasomal degradation by ubiquitination, abnormal cellular localization, and transcriptional regulation are also involved in the inactivation of TSGs. This review incorporates these novel additional mechanisms of TSG inactivation into the existing two-hit model and proposes a revised multiple-hit model that will enable the identification of novel TSGs that can be used as prognostic and predictive biomarkers of cancer.

Establishing an innovative carbohydrate metabolic pathway for efficient production of 2-keto-L-gulonic acid in Ketogulonicigenium robustum initiated by intronic promoters.

BACKGROUND: 2-Keto-L-gulonic acid (2-KGA), the precursor of vitamin C, is currently produced by two-step fermentation. In the second step, L-sorbose is transformed into 2-KGA by the symbiosis system composed of Ketogulonicigenium vulgare and Bacillus megaterium. Due to the different nutrient requirements and the uncertain ratio of the two strains, the symbiosis system significantly limits strain improvement and fermentation optimization. RESULTS: In this study, Ketogulonicigenium robustum SPU_B003 was reported for its capability to grow well independently and to produce more 2-KGA than that of K. vulgare in a mono-culture system. The complete genome of K. robustum SPU_B003 was sequenced, and the metabolic characteristics were analyzed. Compared to the four reported K. vulgare genomes, K. robustum SPU_B003 contained more tRNAs, rRNAs, NAD and NADP biosynthetic genes, as well as regulation- and cell signaling-related genes. Moreover, the amino acid biosynthesis pathways were more complete. Two species-specific internal promoters, P1 (orf_01408 promoter) and P2 (orf_02221 promoter), were predicted and validated by detecting their initiation activity. To efficiently produce 2-KGA with decreased CO2 release, an innovative acetyl-CoA biosynthetic pathway (XFP-PTA pathway) was introduced into K. robustum SPU_B003 by expressing heterologous phosphoketolase (xfp) and phosphotransacetylase (pta) initiated by internal promoters. After gene optimization, the recombinant strain K. robustum/pBBR-P1_xfp2502-P2_pta2145 enhanced acetyl-CoA approximately 2.4-fold and increased 2-KGA production by 22.27% compared to the control strain K. robustum/pBBR1MCS-2. Accordingly, the transcriptional level of the 6-phosphogluconate dehydrogenase (pgd) and pyruvate dehydrogenase genes (pdh) decreased by 24.33 ± 6.67 and 8.67 ± 5.51%, respectively. The key genes responsible for 2-KGA biosynthesis, sorbose dehydrogenase gene (sdh) and sorbosone dehydrogenase gene (sndh), were up-regulated to different degrees in the recombinant strain. CONCLUSIONS: The genome-based functional analysis of K. robustum SPU_B003 provided a new understanding of the specific metabolic characteristics. The new XFP-PTA pathway was an efficient route to enhance acetyl-CoA levels and to therefore promote 2-KGA production.

Targeting ALDH2 with disulfiram/copper reverses the resistance of cancer cells to microtubule inhibitors.

Disulfiram (DSF) in combination with copper (Cu) has been reported to override drug resistance in cancer cells, and DSF combined with chemotherapy based on the microtubule inhibitor vinorelbine appears to prolong survival in non-small cell lung cancer patients. Here, we investigated the mechanisms underlying these findings. DSF/Cu reversed the microtubule inhibitor resistance in A549/Taxol and KB/VCR cells in vitro, and had anti-tumor effects in A549/Taxol and KB/VCR xenograft mice. DSF/Cu and DSF reduced the cancer stem cell (CSC) characteristics of drug-resistant A549/Taxol and KB/VCR cells, including sphere formation, colony generation and migration, and DSF/Cu was more effective than DSF alone. DSF/Cu also decreased the aldehyde dehydrogenase (ALDH) activity and the expression of P-gp and stem cell transcription factors in A549/Taxol and KB/VCR cells. Knockdown of ALDH2 attenuated the CSC characteristics of resistant cancer cells and enhanced their sensitivity to Taxol or VCR. Importantly, DSF/Cu treatment inhibited the expression of ALDH2 in vitro and in vivo. Our findings suggest that DSF/Cu reverses microtubule inhibitor resistance in cancer cells by suppressing ALDH2 expression, and Cu improves the activity of DSF.

Disulfiram combined with copper inhibits metastasis and epithelial-mesenchymal transition in hepatocellular carcinoma through the NF-κB and TGF-ß pathways.

Late-stage hepatocellular carcinoma (HCC) usually has a low survival rate because of the high risk of metastases and the lack of an effective cure. Disulfiram (DSF) has copper (Cu)-dependent anticancer properties in vitro and in vivo. The present work aims to explore the anti-metastasis effects and molecular mechanisms of DSF/Cu on HCC cells both in vitro and in vivo. The results showed that DSF inhibited the proliferation, migration and invasion of HCC cells. Cu improved the anti-metastatic activity of DSF, while Cu alone had no effect. Furthermore, DSF/Cu inhibited both NF-κB and TGF-ß signalling, including the nuclear translocation of NF-κB subunits and the expression of Smad4, leading to down-regulation of Snail and Slug, which contributed to phenotype epithelial-mesenchymal transition (EMT). Finally, DSF/Cu inhibited the lung metastasis of Hep3B cells not only in a subcutaneous tumour model but also in an orthotopic liver metastasis assay. These results indicated that DSF/Cu suppressed the metastasis and EMT of hepatic carcinoma through NF-κB and TGF-ß signalling. Our study indicates the potential of DSF/Cu for therapeutic use.

Oligomer procyanidins (F2) repress HIF-1α expression in human U87 glioma cells by inhibiting the EGFR/ AKT/mTOR and MAPK/ERK1/2 signaling pathways in vitro and in vivo.

Hypoxia-inducible factor-1 (HIF-1) is over-expressed in gliomas and has become one of the most compelling tumor targets. In this study, we found that oligomer procyanidins (F2) can suppress the expressions of HIF-1α and its target genes in U87 cells, and also down-regulate the EGFR/PI3K/AKT/mTOR and MAPK/ERK1/2 pathways in vitro and in vivo. Furthermore, hypoxia-induced formation of tubular structures by human umbilical vascular endothelial cells and the migration and invasion of U87 cells could be inhibited by F2 in a HIF-1 dependent manner. Moreover, in a U87 xenograft tumor model, F2 significantly reduced intra-tumor vessel density and cell proliferation and finally retarded tumor growth, indicating that F2 may be a potential HIF-1 inhibitor and serve as one of candidates for glioma therapy.

Minimally Invasive Transforaminal Lumbar Interbody Fusion and Unilateral Fixation for Degenerative Lumbar Disease.

OBJECTIVE: To evaluate the clinical effect of the minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation using a tubular retractor in the management of degenerative lumbar disease. METHODS: A retrospective analysis was conducted to analyze the clinical outcome of 58 degenerative lumbar disease patients who were treated with minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation during December 2012 to January 2015. The spine was unilaterally approached through a 3.0-cm skin incision centered on the disc space, located 2.5 cm lateral to the midline, and the multifidus muscles and longissimus dorsi were stripped off. After transforaminal lumbar interbody fusion and posterolateral fusion the unilateral pedicle screw fixation was performed. The visual analogue scale (VAS) for back and leg pain, the Oswestry disability index (ODI), and the MacNab score were applied to evaluate clinical effects. The operation time, peri-operative bleeding, postoperative time in bed, hospitalization costs, and the change in the intervertebral height were analyzed. Radiological fusion based on the Bridwell grading system was also assessed at the last follow-up. The quality of life of the patients before and after the operation was assessed using the short form-36 scale (SF-36). RESULTS: Fifty-eight operations were successfully performed, and no nerve root injury or dural tear occurred. The average operation time was 138 ± 33 min, intraoperative blood loss was 126 ± 50 mL, the duration from surgery to getting out of bed was 46 ± 8 h, and hospitalization cost was 1.6 ± 0.2 ten thousand yuan. All of the 58 patients were followed up for 7-31 months, with an average of 14.6 months. The postoperative VAS scores and ODI score were significantly improved compared with preoperative data (P < 0.05). The evaluation of the MacNab score was excellent in 41 patients, good in 15, and fair in 2, suggesting an effective rate of 96.6%. The intervertebral height had reduced 0.2 ± 1.2 mm by the last follow-up, and there were 55 Grade I and II cases based on the Bridwell evaluation criterion. The fusion rate was 94.8%, and no screw breakage and loosening occurred. The scores of physical pain, general health, social, and emotional functioning were significantly increased at the last follow-up. CONCLUSION: Minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation provide a new choice for degenerative lumbar disease, and the short-term clinical outcome is satisfactory.

Pseudoginsenoside-F11 attenuates cerebral ischemic injury by alleviating autophagic/lysosomal defects.

AIMS: Pseudoginsenoside-F11 (PF11), an ocotillol-type ginsenoside, has been reported to exert wide-ranging neuroprotective properties. The aim of this study was to investigate the effect and potential mechanisms of PF11 on the autophagic/lysosomal pathway following ischemic stroke. METHODS: Male Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (pMCAO). Cerebral ischemia outcome, TUNEL staining, Fluoro-Jade B staining were carried out 24 hours poststroke. The autophagic/lysosomal-related proteins were measured. RESULTS: A single administration of PF11 significantly decreased the infarct area, reduced the brain water content, and improved neurological functions, even 4 hours after the onset of pMCAO. Meanwhile, PF11 lessened the ischemic insult-mediated loss of neurons and activation of astrocytes and microglia. Furthermore, PF11 attenuated pMCAO-induced accumulations of autophagosomes and apoptosis. We further observed a remarkable effect of PF11 in reversing the ischemic insult-induced accumulation of autophagosomes (LC3-II) and abnormal aggregation of autophagic proteins (SQSTM1 and ubiquitin). Furthermore, PF11 was capable of improving lysosomal function and lysosome/autophagosome fusion following pMCAO, and this change was reversed by the lysosomal inhibitor chloroquine. Also, the improvement of ischemic outcome and the antiapoptotic effect induced by PF11 was reversed by CQ. CONCLUSION: These findings indicate that the autophagic flux is impaired in a rat model of pMCAO, and that PF11 exerts an excellent protective effect against ischemic stroke by alleviating autophagic/lysosomal defects.

Antioxidant and cytotoxic lignans from the roots of Bupleurum chinense.

In the search for biologically active compounds from the roots of Bupleurum chinense D C., phytochemical investigation of its ethanol extract led to the isolation and identification of a new 8-O-4' neolignan glucoside, saikolignanoside A (1), along with eight known lignans (2-9). Their structures were determined on the basis of IR, UV, HRESIMS, and NMR spectroscopic analyses. The antioxidant and cytotoxic effects of isolated compounds were evaluated in vitro. The isolated compounds (IC50 > 200 µM) did not display 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Whereas compounds 1-2, 5, 7, and 9 exhibited potent 2, 2'-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging properties with IC50 values ranging from 8.34 to 15.24 µM, while compounds 3-4, 6, 8 showed moderate properties. In addition, all compounds were evaluated for cytotoxicities against A549, HepG2, U251, Bcap-37, and MCF-7 cell lines. Compounds 5 and 9 (IC50 < 51.62 µM) possessed stronger cytotoxic activities against all the tested tumor cell lines, compared with the positive control 5-Fluorouracil.

Anti-tumor activity of SL4 against breast cancer cells: induction of G2/M arrest through modulation of the MAPK-dependent p21 signaling pathway.

SL4, a chalcone-based compound, has been shown to retard tumor invasion and angiogenesis by suppressing HIF1 activity and to induce apoptosis by promoting ROS release. Here, we report that SL4 is able to inhibit the proliferation of different types of breast cancer cell in vitro and in vivo by inducing G2/M cell cycle arrest. Our results showed that SL4 exhibited strong anti-proliferative activity in several human breast cancer cell lines, with IC50 values lower than 1.3 µM. Further studies indicated that SL4 induced G2/M arrest in these cell lines. Mechanistically, SL4 reduces the expression of cyclin A2 and cdc25C and decreases the activity of the cdc2/cyclin B1 complex. Notably, SL4 treatment resulted in an obvious increase in p21 mRNA and protein levels through activation of MAPK signaling pathways, but not the TGF-ß pathway. SP600125 and PD98059, specific inhibitors of JNK kinase and ERK kinase, significantly blocked the SL4-induced G2/M phase arrest and upregulation of p21. Furthermore, SL4 suppressed the growth of established breast tumors in nude mice through upregulation of p21 and downregulation of cdc25C, and displayed a good safety profile. Taken together, these findings demonstrate the potential value of SL4 as a novel multi-target anti-tumor drug candidate.

SYP-5, a novel HIF-1 inhibitor, suppresses tumor cells invasion and angiogenesis.

Hypoxia-inducible factor-1 (HIF-1) plays an essential role in carcinogenesis. The overexpression of HIF-1 induced by hypoxia is closely associated with metastasis, poor prognosis and high mortality. In this study, a novel HIF-1 inhibitor SYP-5 was first observed by the luciferase reporter assay. Western blots results showed SYP-5 inhibited hypoxia-induced upregulation of HIF-1. Moreover, the proteins of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 that are targets of HIF-1, were down-regulated by SYP-5. Furthermore, in the tube formation assay, SYP-5 suppressed angiogenesis induced by hypoxia and VEGF in vitro. Additionally, using Transwell and RTCA assays, we found that SYP-5 also retarded the Hep3B and Bcap37 cells migration and invasion induced by hypoxia and FBS. Last, we also detected the upstream pathways related to HIF-1 and found both PI3K/AKT and MAPK/ERK were involved in the SYP-5 mediated invasive inhibition of Bcap37 cells. These results indicates that SYP-5 inhibits tumor cell migration and invasion, as well as tumor angiogenesis, which are mediated by suppressing PI3K/AKT- and MAPK/ERK-dependent HIF-1 pathway. It suggests that SYP-5 might be a potential HIF-1 inhibitor as an anticancer agent.

Neurological mechanism of Xiaochaihutang's antidepressant-like effects to socially isolated adult rats.

OBJECTIVES: Xiaochaihutang (XCHT) has antidepressant effects in multiple animal models of depression in our previous studies. But the antidepressant effects and exact mechanisms of XCHT in a rat model of chronic social isolation stress (CSIS) have never been studied. We therefore aimed to investigate the effects of XCHT on depressive/anxiety-related behaviours of CSIS-exposed rats and understand the neurological mechanism involving neurogenesis. METHODS: We established the CSIS model and then investigated the effects of XCHT on behavioural change. HPLC-MS/MS was adopted to quantify neurotransmitter levels in the cerebrospinal fluid (CSF). Immunofluorescence technology was used to study the effects of XCHT on neurogenesis; while expressions of 5-HT1A receptor signalling pathway in the hippocampus were measured using Western blotting. KEY FINDINGS: Xiaochaihutang significantly alleviated depressive/anxiety-like behaviours of CSIS-exposed rats. XCHT significantly regulated levels of monoamine neurotransmitters in the CSF without affecting Glu, GABA and ACh. XCHT also significantly increased neurogenesis in CSIS-exposed rats. Additionally, XCHT reversed CSIS-induced decrease of 5-HT1A receptor expression and promoted the expression of BDNF in the hippocampus. CONCLUSION: Our results suggest that XCHT could significantly regulate the depressive/anxiety-like behaviours induced by CSIS, which are likely attributed to the promotion of hippocampal neurogenesis and neurotrophin expressions through the activation of serotonergic system.

Aggregated single-walled carbon nanotubes attenuate the behavioural and neurochemical effects of methamphetamine in mice.

Methamphetamine (METH) abuse is a serious social and health problem worldwide. At present, there are no effective medications to treat METH addiction. Here, we report that aggregated single-walled carbon nanotubes (aSWNTs) significantly inhibited METH self-administration, METH-induced conditioned place preference and METH- or cue-induced relapse to drug-seeking behaviour in mice. The use of aSWNTs alone did not significantly alter the mesolimbic dopamine system, whereas pretreatment with aSWNTs attenuated METH-induced increases in extracellular dopamine in the ventral striatum. Electrochemical assays suggest that aSWNTs facilitated dopamine oxidation. In addition, aSWNTs attenuated METH-induced increases in tyrosine hydroxylase or synaptic protein expression. These findings suggest that aSWNTs may have therapeutic effects for treatment of METH addiction by oxidation of METH-enhanced extracellular dopamine in the striatum.