Photoacoustic Spectroscopy Gas Detection Technology Research Progress.

Photoacoustic spectroscopy (PAS) can be utilized as an ultrasensitive gas detection method. The basic principles of gas detection using PAS are discussed in this paper. First, the basic instrumentation for a PAS gas detection system is introduced focusing on the photoacoustic cell. The discussion includes non-resonant photoacoustic cells and the different types of resonant photoacoustic cells, including the longitudinal photoacoustic cell, the Helmholtz photoacoustic cell, the T-type photoacoustic cell, and the high-frequency resonant photoacoustic cell. The basic working principles of each of these, cells as well as the advantages and disadvantages of photoacoustic cells are discussed, and the development of newer types of photoacoustic cells in recent years is outlined in detail. This review provides detailed reference information and guidance for interested researchers who would like to design and build advanced photoacoustic cells for gas detection.

Determination of neurotoxic shellfish poisoning toxins in shellfish by liquid chromatography-tandem mass spectrometry coupled with dispersive solid phase extraction.

An innovative method based on dispersive solid phase extraction (d-SPE) in conjunction with LC-MS/MS had been developed for the simultaneous quantitative determination of three brevetoxins (BTXs), which can result in neurotoxic shellfish poisoning (NSP), in shellfish. The toxins were extracted with a 50 % acetonitrile (v/v) and cleaned by alumina-neutral sorbent. After chromatographic separation on a C18 column, the analytes were qualitatively and quantitatively detected using multiple reaction monitoring (MRM) in positive ionization mode. The created approach was validated by SANTE 11312/2021. The LOQs were 5 µg/kg for each toxin, below the advised regulatory limit of 800 µg BTX-2/kg. The mean recoveries of brevetoxins were in the range of 75.9 %-114.1 %, and the ranges of their intra- and inter-day precisions were 0.9-9.7 % and 0.6-7.2 %, respectively. The matrix effects for three BTXs in four shellfish matrices were in the range of 85.6 %-114.8 %. The method demonstrated great consistency and high sensitivity, and it can meet the requirements of daily monitoring.

Low Dimensional Nanostructure-Assisted Long-Range Surface Plasmon Resonance Sensors With High Figure of Merit.

Long-range surface plasmon resonance (LRSPR) sensors have been extensively studied by virtue of their extremely narrow full width at half maxima (FWHM) characteristics, but their low sensitivity remains an important factor limiting the figure of merit (FOM), making the sensors have difficulties in detecting small refractive index changes accurately. To address this problem, this paper proposes and demonstrates a low dimensional nanostructure (Au nanospheres, WS2) assisted LRSPR sensor to achieve an effective enhancement of the sensor interfaced electric field and thus improve the sensitivity. The performance parameters of the two sensors are compared with the LRSPR sensor by finite element method analysis, and the results showed that the assistance of the low dimensional nanostructure has a positive effect on the sensor. The first refractive index sensing experiment of the WS2-assisted LRSPR sensor was realized with a 25.47% increase in sensitivity and a 7.13% increase in FOM simultaneously, and the Au nanospheres-assisted LRSPR sensor with a 29.23% increase in sensitivity and a 15.95% increase in FOM simultaneously. The introduction of low dimensional nanostructures provides a flexible and effective means of sensitization for LRSPR sensors, making the plasmon resonance sensors combine high sensitivity, narrow FWHM and high FOM, which have promising applications in biochemical sensing.

Piceatannol protects rat neuron cells from oxygen-glucose deprivation reperfusion injury via regulation of GSK-3ß/Nrf2 signaling pathway.

OBJECTIVE: To investigate the effect and mechanism of piceatannol on cerebral ischemia-reperfusion injury. METHODS: The oxygen-glucose deprivation reperfusion (OGD/R) model was constructed in primary cultured suckling rat cortical neuron cells. After 2 h of oxygen-glucose deprivation, the cells were treated with piceatannol for 24 h. The cell survival rate was detected by MTT assay, and the degree of cell damage was detected by intracellular lactate dehydrogenase (LDH) release assay. The activity of superoxide dismutase (SOD) and the content of adenosine triphosphate (ATP) were detected by colorimetric method. The content of reactive oxygen species (ROS) was detected by flow cytometry or observed with inverted fluorescence microscope. The ultrastructure of mitochondria was observed with transmission electron microscopy. Western blotting was used to detect the phosphorylation levels of protein kinase B (AKT) and glycogen synthase kinase (GSK)-3ß. Immunofluorescence staining was used to observe the nuclear localization of nuclear factor-erythroid 2-related factor (Nrf) 2. After OGD/R neuron cells were pretreated with Nrf2 inhibitor ML385 for 24 h, the effect of Nrf2 on the improvement of cell activity and antioxidant activity of piceatannol were investigated. Western blotting was used to detect the protein expression levels of Nrf2, heme oxygenase (HO) 1 and NADPH quinone oxidoreductase (NQO) 1. RESULTS: Piceatannol significantly increased the survival rate of OGD/R neurons, decreased LDH release and reactive oxygen species content, increased SOD activity, ameliorated mitochondrial ultrastructural damage, increased mitochondrial membrane potential and ATP level (all P<0.05), increased phosphorylation of AKT and GSK-3ß protein, up-regulated the expression of Nrf2, HO-1 and NQO1 protein, increased the nuclear-to-plasma ratio of Nrf2, and promoted the nuclear transfer of Nrf2 (all P<0.05). ML385 could significantly reverse the rescue effect of paclitaxel on the model cells and the regulatory activities of SOD, ROS and LDH (all P<0.05). CONCLUSION: Piceatannol can regulate Nrf2 by activating GSK-3ß signaling pathway, promote its nuclear translocation, exert corresponding antioxidant effect, and protect mitochondrial structure and function in rat neuron cells.

Pinus massoniana needle extracts attenuate oxidative stress injury in cerebral ischemia reperfusion rats by regulating JNK3/caspase-3 signal transduction.

OBJECTIVE: To investigate the effect and mechanism of Pinus massoniana needle extracts (PNE) on oxidative stress injury in cerebral ischemia reperfusion rats. METHODS: The SD male rats were randomly divided into sham group, model control group, Edaravone (3 mg/kg) group, PNE low-dose (200 mg/kg), medium-dose (400 mg/kg) and high-dose (800 mg/kg) groups. PNE was administered by gavage for 7 d before modeling and 6 h after modeling in PNE treatment groups; Edaravone was given by intraperitoneal injection 7 d before modeling and 6 h after reperfusion. The rat model of cerebral ischemia reperfusion injury was established by middle cerebral artery occlusion method. After 24 h of reperfusion, the neurological deficit score, brain water content and cerebral infarction volume of rats were measured. The pathological changes of cerebral cortex and hippocampus were observed by HE staining, and the number of normal nerve cells was counted. The apoptosis rate of neurons in cerebral cortex was detected by TUNEL method. The content of nitric oxide (NO), malondialdehyde (MDA) and superoxide dismutase (SOD) activity in ischemic brain tissue were detected. The protein expression of c-Jun N-terminal kinase (JNK) 3, phosphorylated JNK3 (p-JNK3), B-cell lymphoma protein(Bcl) -2, Bcl-2 associated X (Bax), cytochrome C and caspase-3 in cerebral cortex were detected by Western blotting method. RESULTS: Compared with the model control group, the behavioral score, brain water content and cerebral infarction volume in PNE groups were significantly reduced (all P<0.05), the pathological damage of cerebral cortex and hippocampal CA1 area was significantly alleviated, and the number of normal nerve cells in ischemic cortex and hippocampal CA1 area was increased (all P<0.05). The medium-dose PNE group had the best effect. Compared with the model control group, the apoptosis rate of cortical neurons, the content of NO and MDA in cerebral cortex, the ratio of p-JNK3/JNK3, the expression level of cytochrome C and caspase-3 protein in PNE medium-dose group were significantly reduced , and the activity of SOD, the Bcl-2/Bax ratio were significantly improved (all P<0.05). CONCLUSION: PNE ameliorates brain injury after cerebral ischemia reperfusion in rats, which may be related to scavenging NO and MDA, inhibiting oxidative stress-mediated JNK3/caspase-3 signsal transduction to inhibit neuronal apoptosis.

Research advances on surface plasmon resonance biosensors.

The surface plasmon resonance (SPR) phenomenon is of wide interest due to its sensitivity to changes in surface refractive index for the label-free, highly sensitive and rapid detection of biomarkers. This paper reviews research progress on SPR biosensors modified with different substrate structures and surface materials, surface plasmon resonance imaging (SPRI), and SPR-enhanced electrochemiluminescent (ECL) biosensors for applications in biosensing in the last five years. This paper focuses on the research on the application of the SPR phenomenon in the field of bio-detection, reviews the sensing characteristics of SPR biosensors with substrate structures of prisms, gratings, and optical fibers, and summarizes and analyzes the sensitivity and interference resistance of SPR sensors with surface modification of different materials (high-refractive index dielectric films, metallic micro- and nanostructures, and surface antifouling materials). Considering that imaging is an important tool for biomedical detection, this paper reviews the research progress on SPRI technology in the field of biomedical detection. In addition, this paper also reviews the research progress on SPR-enhanced ECL biosensors in the field of biosensing. Finally, this paper provides an outlook on the development trends of biosensing technology in terms of portable high-precision SPR sensors, reduction of self-loss of thin film materials, optimization of image processing techniques and simplification of electrode modification for ECL sensors.

Behavioral and Neurochemical Changes in Rats with Recurrent Depression induced by chronic unpredictable stress.

OBJECTIVES: The mechanism of recurrent depression remains unclear. This study aimed to evaluate the behavioural and neurochemical patterns of rats with recurrent depression. MATERIALS AND METHODS: An animal model of recurrent depression was established using chronic unpredictable stress and imipramine hydrochloride. The behaviour of the rats was tested during the first onset and recurrence periods of depression. The levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT), and cyclic adenosine monophosphate (cAMP) in serum were detected by ELISA. The protein expressions of brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) in the hippocampal dentate gyrus (DG) area of rats were detected by western blotting. RESULTS: The weight and sugar preference of the rats with recurrent depression were significantly decreased, and the immobility time of tail suspension was significantly increased during the first onset and recurrence periods. The modelling time of rats was shortened by one week in the recurrence period compared with that in the first onset. The model rats with recurrent depression had significantly increased ACTH and CORT and significantly decreased cAMP, CREB, and BDNF levels. CONCLUSION: Rats with recurrent depression are highly susceptible to stress and exhibit depression-like behaviours such as weight loss, increased immobility time in tail suspension test, and reduced sucrose preference index. Moreover, the modelling time was shortened by one week, indicating an obvious susceptibility to recurrent depression. The significantly up-regulated neuroendocrine in the HPA and the significantly inhibited BDNF and protein expression factors in related signalling pathways may be involved in the increased susceptibility to recurrent depression.

[Determination of amanita peptide toxins in human urine by TurboFlow online clean-up-liquid chromatography-tandem mass spectrometry].

Amanita peptide toxins are cyclic polypeptide mushroom toxins that can cause acute liver damage. The fatality rate associated with these toxins is very high. Monitoring the concentration of amanita peptide toxins in human urine can provide valuable information for early clinical diagnosis and treatment. Therefore, a TurboFlow online clean-up-liquid chromatography-triple quadrupole mass spectrometry (TF-LC-MS/MS) method was established for the simultaneous quantitative determination of five amanita peptide toxins (α-amanitin, ß-amanitin, γ-amanitin, phallacidin, and phalloidin) in human urine. After pre-treatment with high-speed centrifugation, urine samples were analyzed using TF-LC-MS/MS. The main factors influencing purification efficiency, including the TF column, loading solution, eluting solution, transfer flow, and transfer time, were optimized in this study. Under the optimized experimental conditions, the analytes were purified using a TurboFlowTM Cyclone column (50 mm×0.5 mm) and separated on a Hypersil GOLD C18 column (100 mm×2.1 mm) using the mobile phases of methanol and 4 mmol/L aqueous ammonium acetate solution with gradient elution. The analytes were detected in selected reaction monitoring (SRM) mode via positive electrospray ionization. Matrix-matched external standard calibration was used for quantitation. The linear range of the method ranged from 1.0 µg/L to 50.0 µg/L for all five amanita peptide toxins, with correlation coefficients (r2) higher than 0.997. The limits of detection were 0.15-0.3 µg/L and the limits of quantification (LOQs) were 0.5-1.0 µg/L for the five amanita peptide toxins in urine. The intra-day and inter-day recoveries of amanita peptide toxins were 87.0%-108.6% and 86.8%-112.7%, respectively, at the spiked levels of 2.0, 5.0, and 10.0 µg/L. The intra-day and inter-day relative standard deviations (RSDs) were less than 14.5%. The method is accurate, rapid, sensitive, easy to operate, and can satisfy the requirements of public health emergency testing or clinical poisoning testing.

Protective Effect of Piceatannol Against Cerebral Ischaemia-Reperfusion Injury Via Regulating Nrf2/HO-1 Pathway In Vivo and Vitro.

Piceatannol is a natural plant-derived compound with protective effects against cardiovascular diseases. However, its effect on cerebral ischaemia-reperfusion injury (CIRI) induced by oxidative stress remains unclear. This study aimed to investigate piceatannol's antioxidation in CIRI. An in vitro oxygen-glucose deprivation followed by reoxygenation model was used and cell viability was measured. A middle cerebral artery occlusion followed by reperfusion model was used in vivo. Neurological function, encephalisation quotient, oedema, and volume of the cerebral infarction were then evaluated. The effects of piceatannol on histopathological findings, as well as the ultrastructure of the cortex, were analysed. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and lactate dehydrogenase (LDH) and the malondialdehyde (MDA) content was measured both in vitro and in vivo. Finally, the expression of nuclear factor erythroid-2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase 1 (NQO1) in cerebral tissue was detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting. Our results demonstrated that cell viability in the piceatannol groups was increased. The SOD, GSH-Px activities were increased as LDH activity and MDA content decreased in the piceatannol groups both in vitro and in vivo, reflecting a decrease in oxidative stress. The neurological severity score and infarction volume in the piceatannol groups at doses of 10 and 20 mg/kg were lower than those of the model group. Furthermore, the damage seen on histopathological examination was partially attenuated by piceatannol. RT-qPCR and western blot analysis indicated that the expression of Nrf2, HO-1, and NQO1 were significantly increased by piceatannol. The results of the study demonstrate that piceatannol exerts a protective effect against CIRI.

[Determination of domoic acid in shellfish by liquid chromatography- tandem mass spectrometry coupled with dispersive solid phase extraction].

OBJECTIVE: A method utilizing liquid chromatography-tandem mass spectrometry(LC-MS/MS) coupled with dispersive solid phase extraction for quantitative analysis of domoic acid in four kinds of shellfish was established. METHODS: The sample of 0. 1 g was extracted with 25% methanol aqueous solution, the extract was purified by dispersive solid phase extraction with 50 mg HLB and 5 mg GCB, and then filtered through a PTFE membrane. The analytes were separated on a C_(18) column(100 mm×2. 1 mm, 1. 9 µm), and detected in selected reaction monitoring(SRM) mode via positive electrospray ionization. The matrix matching and external standard method was used for quantitation. RESULTS: Domoic acid showed good linearity in the concentration range between 1. 0 ng/mL and 50. 0 ng/mL with correlation coefficients higher than 0. 9994. The detection limits of domoic acid in shellfish was 5 µg/kg. The inter-and intra-day recoveries were 91. 6%-109. 2% and 90. 9%-109. 3%, respectively. The inter-and intra-day ralitive standard deviations(RSDs) were lower than 8. 2% at spiked concentrations of 20, 50 and 100 µg/kg. CONCLUSION: The method is accurate, fast, easy to operate, which can satisfy the requirements of public health emergency testing or routine testing.

[Protective effect of iridoid glycosides of radix scrophulariae on endoplasmic reticulum stress induced by oxygen-glucose deprivation and reperfusion in vitro model].

OBJECTIVE: To investigate the regulatory effect of iridoid glycoside of radix scrophulariae (IGRS) on endoplasmic reticulum stress induced by oxygen-glucose deprivation and reperfusion in vitro model. METHODS: Rat pheochromocytoma PC12 cells were pretreated with IGRS (50, 100, 200 µg/mL) for 24h, and the in vitro model of oxygen-glucose deprivation/reoxygenation (OGD/R) was applied. The cell viability was determined by MTT and lactate dehydrogenase (LDH) assay. The apoptotic rate was detected by flow cytometry. The expression of B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), C/EBP homologous protein (CHOP), caspase-12 protein, and glucose-regulated protein-78(GRP78)were detected by Western blotting. The mRNA expression levels of sarco/endoplasmic reticulum Ca2+-ATPase2 (SERCA2), 1, 4, 5-triphosphate inositol receptor 1 (IP3R1), and ryanodine receptor 2 (RyR2)were detected by real-time RT-PCR. Free Ca2+ concentration [Ca2+]i was determined by using laser scanning confocal microscopy. RESULTS: The damage caused by OGD/R to PC12 cells was significantly reduced by IGRS, with significant effect on increasing survival rate and reducing LDH release (all P<0.01). The expression of GRP78, CHOP, Bax, and caspase-12 were down-regulated (all P<0.01), and the expression of Bcl-2 and Bcl-2/Bax ratio was up-regulated (all P<0.01); IGRS increased the expression of SERCA2 mRNA in PC12 cells after OGD/R injury (P<0.01), decreased [Ca2+]i and down-regulated the expression of RyR2 mRNA and IP3R1 mRNA. CONCLUSIONS: IGRS has neuroprotective effect, which may alleviate cerebral ischemia-reperfusion injury by regulating SERCA2, maintaining calcium balance, and inhibiting endoplasmic reticulum stress-mediated apoptosis.

Iridoid glycosides from Radix Scrophulariae attenuates focal cerebral ischemia­reperfusion injury via inhibiting endoplasmic reticulum stress­mediated neuronal apoptosis in rats.

Iridoid glycosides of Radix Scrophulariae (IGRS) are a group of the major bioactive components from Radix Scrophulariae with extensive pharmacological activities. The present study investigated the effects of IGRS on cerebral ischemia­reperfusion injury (CIRI) and explored its potential mechanisms of action. A CIRI model in rats was established by occlusion of the right middle cerebral artery for 90 min, followed by 24 h of reperfusion. Prior to surgery, 30, 60 or 120 mg/kg IGRS was administered to the rats once a day for 7 days. Then, the neurological scores, brain edema and volume of the cerebral infarction were measured. The apoptosis index was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling. The effects of IGRS on the histopathology of the cortex in brain tissues and the endoplasmic reticulum ultrastructure in the hippocampus were analyzed. Finally, the expression of endoplasmic reticulum stress (ERS)­regulating mediators, endoplasmic reticulum chaperone BiP (GRP78), DNA damage­inducible transcript 3 protein (CHOP) and caspase­12, were detected by reverse transcription quantitative polymerase chain reaction (RT­qPCR) and western blot analysis. The volume of cerebral infarction and brain water content in the IGRS­treated groups treated at doses of 60 and 120 mg/kg were decreased significantly compared with the Model group. The neurological scores were also significantly decreased in the IGRS­treated groups. IGRS treatment effectively decreased neuronal apoptosis resulting from CIRI­induced neuron injury. In addition, the histopathological damage and the endoplasmic reticulum ultrastructure injury were partially improved in CIRI rats following IGRS treatment. RT­qPCR and western blot analysis data indicated that IGRS significantly decreased the expression levels of GRP78, CHOP and caspase­12 at both mRNA and protein levels. The results of the present study demonstrated that IGRS exerted a protective effect against CIRI in brain tissue via the inhibition of apoptosis and ERS.

Determination of carbazole and halogenated carbazoles in human serum samples using GC-MS/MS.

Carbazole and halogenated carbazoles have been widely detected throughout the environment in soil, river deposits, and lake sediments. Human exposure to these compounds may occur through inhalation, drinking water, dietary intake and/or skin contact, and exposure levels in the body may be evaluated by measuring them in serum or blood. This paper reports the method development and validation for the analysis of carbazole and 11 halogenated carbazoles in human blood and/or serum samples. A small sample size of 100 µL of blood or serum was employed for the analysis. The samples were prepared through salting-out liquid-liquid extraction (LLE) by using hexane/ethyl acetate (4:1, v/v) as the extraction solvent and aqueous MgSO4 (37.5 wt%) as the salting-out regent, respectively. Sample analysis was performed using gas-chromatography (GC) coupled with a tandem mass spectrometer (MS/MS) in an electron impact (EI) mode. The developed method demonstrated low detection limits in the range of 0.02-0.27 ng/mL, intra-day accuracy ranging from 81.2% to 125%, and inter-day accuracy from 91.0% to 117%. The intra- and inter-day precisions, calculated by relative standard deviations (RSDs), were in the ranges of 1.0-16.0% and 1.8-16.4%, respectively. The developed method was applied to the analysis of 50 human serum samples collected from pregnant women in Southern California in 2012. Low concentrations of carbazole were measured in 18 samples, while halogenated carbazoles were not detected in any of the samples.

Total glucosides of peony improve ovalbumin-induced allergic asthma by inhibiting mast cell degranulation.

ETHNOPHARMACOLOGICAL RELEVANCE: Paeonia lactiflora Pall. (peony) is a medicinal plant used in the Xiaoqinglong decoction, a commonly prescribed traditional Chinese medicine for asthma. The main active ingredients of peony roots-described as the total glucosides of peony (TGP)-have anti-inflammatory, immunomodulatory, and protective effects on endothelial cells, and they are known to improve rheumatoid arthritis. This study explored the underlying mechanism of TGP activity in the treatment of allergic asthma. MATERIALS AND METHODS: Allergic asthma was induced in BALB/c mice by administering injections of ovalbumin (OVA) mixed with aluminum hydroxide gel and inhaling nebulized OVA. The OVA-sensitized mice were treated with TGP by oral gavage, and the potentially anti-asthmatic treatment effect was studied by testing airway hyperresponsiveness, classifying and counting of leukocytes, performing cytokine assays, and analyzing the lung histopathology. The ß-hexosaminidase activity was assayed as a biomarker to evaluate the effect of TGP on mast cell degranulation. The mechanism of TGP was explored by monitoring the Ca2+ influx level in mast cells (RBL-2H3) using a Ca2+ fluorescent probe technique. RESULTS: In mice with OVA-induced allergic asthma, TGP reduced airway hyperresponsiveness and improved lung tissue pathology, which included a decrease in inflammatory cell infiltration and collagen deposition. TGP also significantly lowered BALF leukocyte, eosinophil, and neutrophil counts, along with chemokines and cytokines, such as eotaxin, TNF-α, IL-4, and MIP-1α, in serum and lungs of OVA-challenged mice. These effects were further confirmed with the decrease of ß-hexosaminidase release and the inhibition of Ca2+ influx in mast cell degranulation. CONCLUSIONS: Our findings suggest that TGP improved OVA-induced allergic asthma in mice mainly by suppressing Ca2+ influx-dependent mast cell degranulation.

Promoting neurogenesis in hippocampal dentate gyrus of chronic unpredictable stress-induced depressive-like rats with paeoniflorin.

Hippocampal neurogenesis plays an important role in the onset and treatment of depressive disorders. Previous studies suggest that paeoniflorin could be used as an antidepressant for treating rats subjected to chronic unpredictable stress. In this study, the effects of paeoniflorin on neurogenesis in the hippocampus dentate gyrus and potential mechanism of action are further investigated in chronic unpredictable stress-induced rat. Results suggest that paeoniflorin markedly increased both sucrose consumption and the number of 5-bromo-2-deoxyuridine-positive cells in the dentate gyrus of chronic unpredictable stress-induced rats, and the ratio of co-expressed 5-bromo-2-deoxyuridine and glial fibrillary acidic protein-positive cells, but exerted no significant effect on the ratio of co-expressed 5-bromo-2-deoxyuridine and neuronal nuclei-positive cells. Compared with the vehicle group, a significant increase was detected in the number of brain-derived neurotrophic factor-positive cells and the expression of brain-derived neurotrophic factor mRNA in the hippocampus of the paeoniflorin-treated group. According to the results, paeoniflorin promoted neural stem cell proliferation, their differentiation into astrocytes, and neurogenesis in the hippocampal dentate gyrus of chronic unpredictable stress-induced rats. Apart from enhancing the protein expression and gene transcription of brain-derived neurotrophic factor, it also activated the expression of tropomyosin receptor kinase B (a high-affinity receptor of brain-derived neurotrophic factor). This suggests that paeoniflorin might promote neurogenesis in the hippocampus dentate gyrus of chronic unpredictable stress-induced rats and act as an antidepressant by regulating the brain-derived neurotrophic factor-tropomyosin receptor kinase B signaling pathway.

[Determination of nitroimidazoles and their metabolites in animal-derived foods by liquid chromatography-tandem mass spectrometry coupled with dispersive solid phase extraction].

A method for the quantitative analysis of nitroimidazoles and their metabolites in four kinds of animal-derived foods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with dispersive solid phase extraction (dSPE) was established. The samples (2.0 g) were extracted with ethyl acetate. The extracts were degreased with hexane and purified with 50 mg primary-secondary amine (PSA), and then filtered through a hydrophilic polytetrafluoroethylene (PTFE) membrane. The analytes were separated on a C18 column, and detected in selected reaction monitoring (SRM) mode via positive electrospray ionization. The matrix matching and internal standard method was used. The nitroimidazoles and their metabolites showed good linearity in the range of 0.5-20.0 µg/L with correlation coefficients greater than 0.99. The limits of detection of the nitroimidazoles and their metabolites in animal-derived foods were between 0.1 and 0.5 µg/kg. The recoveries varied between 84.2% and 120.8%, with relative standard deviations (n=6) ranging from 2.0% to 16.2% at spiked levels of 1.0, 3.0, and 10.0 µg/kg. The proposed method is accurate, fast, cheap, easy, and can satisfy the requirements of monitoring nitroimidazoles and their metabolites in animal-derived foods.

Paeoniflorin Ameliorates Chronic Stress-Induced Depression-Like Behaviors and Neuronal Damages in Rats via Activation of the ERK-CREB Pathway.

Neuronal damage is related to the onset and treatment of depressive disorders. Antidepressant-like effects have been elicited by paeoniflorin on animal models. The aim of this study is to demonstrate whether the neuroprotective effect of paeoniflorin on rats suffered from chronic unpredictable mild stress (CUMS) was regulated by the ERK-CREB signaling pathway. Results showed that paeoniflorin not only ameliorated depressive-like behavior with low locomotor activity and prolonged immobility duration in our forced swimming test but also reduced sucrose consumption. Paeoniflorin treatment decreased the degree of neuronal damage in the hippocampus of the model rats. Conversely, it markedly increased the mRNA levels of ERK1, ERK2, and CREB and the levels of ERK, p-ERK, CREB, and p-CREB protein expression in the hippocampus. Blockade of the ERK-CREB axis with the ERK-specific inhibitor U0126 repressed the neuroprotective and antidepressant-like effects of paeoniflorin on rats in the setting of chronic-mild-stress and abolished the recoveries of p-ERK mediated by paeoniflorin treatment. Thus, paeoniflorin possibly exerted a neuroprotective effect modulated by the ERK-CREB signaling pathway on CUMS-induced hippocampal damage in rats.

Therapeutic mechanisms of single Chinese medicine herb or their extracts for extrahepatic obstructive jaundice.

Obstructive jaundice (OJ) is classified as extrahepatic OJ or intrahepatic OJ. Extrahepatic OJ is attributed to a variety of intricate etiological factors. Research has begun with Chinese medicine (CM), which can be used as an adjunctive therapy for extrahepatic OJ. Particular attention has been paid to the therapeutic effects and their mechanisms of single CM herb and relevant extracts. The roles of single CM or their extracts during adjunctive therapy for extrahepatic OJ have been described briefly. This review focuses on the effects and their mechanisms of relevant herbal medicines.

The antidepressant-like effects of paeoniflorin in mouse models.

Peony is often used in Chinese herbal medicine for the treatment of depression-like disorders. Our previous studies have demonstrated that the total glycosides of peony exert antidepressant-like effects in animal models. Paeoniflorin is the main active glycoside of peony. The aim of this study was to evaluate the antidepressant-like effects of paeoniflorin in mice, as well as its active mechanisms. The results revealed that intraperitoneally injected paeoniflorin significantly reduced the duration of immobility in forced swimming and tail suspension tests. The doses that affected the immobility response did not affect locomotor activity. Furthermore, paeoniflorin antagonized reserpine-induced ptosis, akinesia and hypothermia. Paeoniflorin also significantly increased the levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus. These results suggest that the upregulation of serotonergic systems may be an important mechanism for the antidepressant-like effects of paeoniflorin in mice.

Antidepressant-like effects of paeoniflorin on the behavioural, biochemical, and neurochemical patterns of rats exposed to chronic unpredictable stress.

We have previously demonstrated that the total glycosides of peony exert antidepressant-like effects in animal models. Paeoniflorin is the main active glycoside of peony. The purpose of this study was to evaluate the antidepressant-like effects of paeoniflorin in a rat model of chronic unpredictable stress (CUS) and its active mechanisms. The results showed that CUS-exposed rats exhibited depressive-like behaviour with reduced weight, low motor activity as well as reduced consumption of sucrose, biochemical changes with increased concentrations of corticosterone and adrenocorticotropic hormone and neurochemical changes with reduced monoamine neurotransmitter levels. Paeoniflorin treatment markedly increased sucrose consumption and decreased serum corticosterone and adrenocorticotropic hormone levels in the CUS-treated rats. Furthermore, paeoniflorin treatment significantly attenuated CUS-induced reductions in noradrenaline, serotonin and its metabolite 5-hydroxyindoleacetic acid as well as CUS-induced increases in the ratio between the latter two factors. These results suggest that the modulation of the hypothalamic-pituitary-adrenal axis and up-regulation of serotonergic and noradrenergic systems are important mechanisms underlying the antidepressant-like effects of paeoniflorin in CUS-treated rats.