Hua-Lin Cai

Determination of dansylated monoamine and amino acid neurotransmitters and their metabolites in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

The determination of neurotransmitters (NTs) and their metabolites facilitates better understanding of complex neurobiology in the central nervous system disorders and has expanding uses in many other fields. We present a liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) method for the quantification of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine (NE), vanillymandelic acid (VMA), 3-methoxy-4-hydroxy phenylglycol (MHPG), 5-hydroxytryptamine (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), glutamate (Glu), and gamma-aminobutyric acid (GABA). The NTs and their metabolites were dansylated and analyzed by an LC gradient on a C18 column on-line with a tandem mass spectrometer. This method exhibited excellent linearity for all of the analytes with regression coefficients higher than 0.99. The lower limit of quantification (LLOQ) values for DA, DOPAC, HVA, NE, VMA, MHPG, 5-HT, 5-HIAA, Glu, and GABA were 0.57, 0.37, 0.35, 0.40, 0.35, 0.91, 0.27, 0.43, 0.65, and 1.62 pmol/ml, respectively. The precision results were expressed as coefficients of variation (CVs), ranging from 1.5% to 13.6% for intraassay and from 2.9% to 13.7% for the interassay. This novel LC-ESI/MS/MS approach is precise, highly sensitive, specific, and sufficiently simple. It can provide an alternative method for the quantification of the NTs and their metabolites in human plasma.

Simultaneous determination of isoniazid, rifampicin, levofloxacin in mouse tissues and plasma by high performance liquid chromatography–tandem mass spectrometry

A rapid and selective high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous determination of isoniazid (INH), rifampicin (RFP) and levofloxacin (LVX) in mouse tissues and plasma has been developed and validated, using gatifloxacin as the internal standard (I.S.). The compounds and I.S. were extracted from tissue homogenate and plasma by a protein precipitation procedure with methanol. The HPLC separation of the analytes was performed on a Welch materials C4 column (250mmx4.6mm, 5.0microm, USA) at 25 degrees C, using a gradient elution program with the initial mobile phase constituting of 0.05% formic acid and methanol (93:7, v/v) at a flow-rate of 1.0ml/min. For all the three analytes, the recoveries varied between 83.3% and 98.8% in tissues and between 75.5% and 90.8% in plasma, the accuracies ranged from 91.7% to 112.0% in tissues and from 94.6% to 108.8% in plasma, and the intra- and inter-day precisions were less than 13.3% in tissues and less than 8.2% in plsama. Calibration ranges for INH were 0.11-5.42microg/g in tissues and 0.18-9.04microg/ml in plasma, for RFP were 0.12-1200microg/g in tissues and 4.0-200microg/ml in plasma, and for LVX were 0.13-26.2microg/g in tissues and 0.09-4.53microg/ml in plasma. The lower limits of quantification (LLOQs) for INH, RFP and LVX in mouse tissues were 0.11, 0.12 and 0.13microg/g and for those in mouse plasma were 18.1, 20.0 and 21.8ng/ml, respectively. The limits of detection (LODs) for INH, RFP and LVX in mouse tissues were 0.04, 0.05 and 0.05microg/g and for those in mouse plasma were 5.5, 6.0 and 6.6ng/ml, respectively. The established method was successfully applied to simultaneous determination of isoniazid, rifampicin and levofloxacin in mouse plasma and different mouse tissues.

Stress and vitamin D: Altered vitamin D metabolism in both the hippocampus and myocardium of chronic unpredictable mild stress exposed rats

Exposure to stressful life events is associated with the onset of major depression and increases the risk of cardiac morbidity and mortality. While recent evidence has indicated the existence of an interrelationship between local vitamin D (VD) metabolism and many aspects of human physiology including brain and heart function, much is still unknown concerning the biological link between VD signaling and stress-induced depressive behavior and cardiac dysfunction. In the present study, we observed the VD intracrine system in the hippocampus and myocardium of chronic unpredictable mild stress (CUMS) exposed rats. After 4 weeks of CUMS procedure, rats were induced to a depressive-like state and the cytochromes P450 enzymes involved in VD activating and catabolizing (CYP27B1 and CYP24A1 respectively) and VD receptor (VDR) were assessed by real time RT-PCR and western blot in the hippocampus, myocardium and kidney. In the hippocampus of depressed rats, CYP27B1, CYP24A1 and VDR expression were significantly increased and the local status of 1,25-dihydroxyvitamin D (1,25(OH)2D) was higher compared with controls. Furthermore, hippocampal mRNA levels of VD target genes (calbindin-d28k, neurotrophin-3) and RXRα (heterodimeric partner of VDR) were upregulated in response to chronic stress. Similar to the hippocampus, CUMS also induced CYP27B1/CYP24A1/VDR expression in the myocardium. However, renal metabolism of VD and serum1,25(OH)2D status were unchanged. Meanwhile, sertraline treatment could partly normalize the stress-induced alterations of VD metabolism. In conclusion, this study firstly showed a co-elevated expression of CYP27B1/CYP24A1/VDR in both the hippocampus and myocardium of CUMS rats, which suggests VD signaling may be involved in the compensatory mechanism that protect from stress-induced deteriorating effects on the brain and heart.

Astragalus polysaccharides can regulate cytokine and P-glycoprotein expression in H22 tumor-bearing mice

AIM To investigate the adjunct anticancer effect of Astragalus polysaccharides in H22 tumor-bearing mice. METHODS To establish a solid tumor model, 5.0 × 10(6)/mL H22 hepatoma cells were inoculated subcutaneously into the right armpit region of Kunming mice (6-12 wk old, 18-22 g). When the tumors reached a size of 100 mm(3), the animals were treated as indicated, and the mice were randomly assigned to seven groups (n = 10 each). After ten days of treatment, blood samples were collected from mouse eyes, and serum was harvested by centrifugation. Mice were sacrificed, and the whole body, tumor, spleen and thymus were weighed immediately. The rate of tumor inhibition and organ indexes were calculated. The expression levels of serum cytokines, P-glycoprotein (P-GP) and multidrug resistance (MDR) 1 mRNA in tumor tissues were detected using enzyme-linked immunosorbent assay, Western blotting, and quantitative myeloid-derived suppressor cells reverse transcription-polymerase chain reaction, respectively. RESULTS The tumor inhibition rates in the treatment groups of Adriamycin (ADM) + Astragalus polysaccharides (APS) (50 mg/kg), ADM + APS (100 mg/kg), and ADM + APS (200 mg/kg) were significantly higher than in the ADM group (72.88% vs 60.36%, P = 0.013; 73.40% vs 60.36%, P = 0.010; 77.57% vs 60.36%, P = 0.001). The spleen indexes of the above groups were also significantly higher than in the ADM group (0.65 ± 0.22 vs 0.39 ± 0.17, P = 0.023; 0.62 ± 0.34 vs 0.39 ± 0.17, P = 0.022; 0.67 ± 0.20 vs 0.39 ± 0.17, P = 0.012), and the thymus indexes of the ADM + APS (100 mg/kg) and ADM + APS (200 mg/kg) groups were significantly higher than in the ADM group (0.20 ± 0.06 vs 0.13 ± 0.04, P = 0.029; 0.47 ± 0.12 vs 0.13 ± 0.04, P = 0.000). APS was found to exert a synergistic anti-tumor effect with ADM and to alleviate the decrease in the sizes of the spleen and thymus induced by AMD. The expression of interleukin-1α (IL-1α), IL-2, IL-6, and tumor necrosis factor-α (TNF-α) was significantly higher in the ADM + APS (50 mg/kg), ADM + APS (100 mg/kg) and ADM + APS (200 mg/kg) groups than in the ADM group; and IL-10 was significantly lower in the above groups than in the ADM group. APS could increase IL-1α, IL-2, IL-6, and TNF-α expression and decrease IL-10 levels. Compared with the ADM group, APS treatment at a dose of 50-200 mg/kg could down-regulate MDR1 mRNA expression in a dose-dependent manner (0.48 ± 0.13 vs 4.26 ± 1.51, P = 0.000; 0.36 ± 0.03 vs 4.26 ± 1.51, P = 0.000; 0.21 ± 0.04 vs 4.26 ± 1.51, P = 0.000). The expression level of P-GP was significantly lower in the ADM + APS (200 mg/kg) group than in the ADM group (137.35 ± 9.20 mg/kg vs 282.19 ± 20.54 mg/kg, P = 0.023). CONCLUSION APS exerts a synergistic anti-tumor effect with ADM in H22 tumor-bearing mice. This may be related to its ability to enhance the expression of IL-1α, IL-2, IL-6, and TNF-α, decrease IL-10, and down-regulate MDR1 mRNA and P-GP expression levels.

Neurochemical effects of chronic administration of calcitriol in rats.

Despite accumulating data showing the various neurological actions of vitamin D (VD), its effects on brain neurochemistry are still far from fully understood. To further investigate the neurochemical influence of VD, we assessed neurotransmitter systems in the brain of rats following 6-week calcitriol (1,25-dihydroxyvitamin D) administration (50 ng/kg/day or 100 ng/kg/day). Both the two doses of calcitriol enhanced VDR protein level without affecting serum calcium and phosphate status. Rats treated with calcitriol, especially with the higher dose, exhibited elevated γ-aminobutyric acid (GABA) status. Correspondingly, the mRNA expression of glutamate decarboxylase (GAD) 67 was increased. 100 ng/kg of calcitriol administration also increased glutamate and glutamine levels in the prefrontal cortex, but did not alter glutamine synthetase (GS) expression. Additionally, calcitriol treatment promoted tyrosine hydroxylase (TH) and tryptophan hydroxylase 2 (TPH2) expression without changing dopamine and serotonin status. However, the concentrations of the metabolites of dopamine and serotonin were increased and the drug use also resulted in a significant rise of monoamine oxidase A (MAOA) expression, which might be responsible to maintain the homeostasis of dopaminergic and serotonergic neurotransmission. Collectively, the present study firstly showed the effects of calcitriol in the major neurotransmitter systems, providing new evidence for the role of VD in brain function.

MultiSimplex optimization of chromatographic separation and dansyl derivatization conditions in the ultra performance liquid chromatography-tandem mass spectrometry analysis of risperidone, 9-hydroxyrisperidone, monoamine and amino acid neurotransmitters in human urine.

A pre-column dansylated ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of risperidone (RIP), 9-hydroxyrisperidone (9-OH-RIP), monoamine and amino acid neurotransmitters in human urine was developed with the aim of providing data on how neurotransmitters may influence each other or change simultaneously in response to risperidone treatment. MultiSimplex based on the simplex algorithm and the fuzzy set theory was applied to the optimization of chromatographic separation and dansyl derivatization conditions during method development. This method exhibited excellent linearity for all the analytes with regression coefficients higher than 0.997. The lower limit of quantification (LLOQ) values for 9-OH-RIP and RIP were 0.11 and 0.06 ng/ml, respectively, and for neurotrasmitters ranged from 0.31 to 12.8 nM. The mean accuracy ranged from 94.7% to 108.5%. The mean recovery varied between 81.6% and 97.5%. All the RSD of precision and stability were below 9.7%. Finally, the optimized method was applied to analyze the first morning urine samples of schizophrenic patients treated with risperidone and healthy volunteers.

Effects of Astragalus polysaccharides on P-glycoprotein efflux pump function and protein expression in H22 hepatoma cells in vitro

BackgroundAstragalus polysaccharides (APS) are active constituents of Astragalus membranaceus. They have been widely studied, especially with respect to their immunopotentiating properties, their ability to counteract the side effects of chemotherapeutic drugs, and their anticancer properties. However, the mechanism by which APS inhibit cancer and the issue of whether that mechanism involves the reversal of multidrug resistance (MDR) is not completely clear. The present paper describes an investigation of the effects of APS on P-glycoprotein function and expression in H22 hepatoma cell lines resistant to Adriamycin (H22/ADM).MethodsH22/ADM cell lines were treated with different concentrations of APS and/or the most common chemotherapy drugs, such as Cyclophosphamid, Adriamycin, 5-Fluorouracil, Cisplatin, Etoposide, and Vincristine. Chemotherapeutic drug sensitivity, P-glycoprotein function and expression, and MDR1 mRNA expression were detected using MTT assay, flow cytometry, Western blotting, and quantitative RT-PCR.ResultsWhen used alone, APS had no anti-tumor activity in H22/ADM cells in vitro. However, it can increase the cytotoxicity of certain chemotherapy drugs, such as Cyclophosphamid, Adriamycin, 5-Fluorouracil, Cisplatin, Etoposide, and Vincristine, in H22/ADM cells. It acts in a dose-dependent manner. Compared to a blank control group, APS increased intracellular Rhodamine-123 retention and decreased P-glycoprotein efflux function in a dose-dependent manner. These factors were assessed 24 h, 48 h, and 72 h after administration. APS down regulated P-glycoprotein and MDR1 mRNA expression in a concentration-dependent manner within a final range of 0.8–500 mg/L and in a time-dependent manner from 24–72 h.ConclusionAPS can enhance the chemosensitivity of H22/ADM cells. This may involve the downregulation of MDR1 mRNA expression, inhibition of P-GP efflux pump function, or both, which would decrease the expression of the MDR1 protein.

Antidepressant-like effect of n-3 PUFAs in CUMS rats: role of tPA/PAI-1 system

BDNF is strongly implicated in the development of depression. Recent evidence has indicated that tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) are related to the cleavage of pro-brain-derived neurotrophic factor (BDNF) into its mature form. Chronic unpredicted mild stress (CUMS) is widely used to induce depressive behaviors in rodents. Therefore, we investigated the effects of PUFAs and sertraline on tPA/PAI-1 system in CUMS rats. After 5 weeks of CUMS procedures, the rats were induced to a depressive-like state. The expressions of PAI-1 and proBDNF were increased in the prefrontal cortex and hippocampus of CUMS rats. N-3 polyunsaturated fatty acids (PUFAs) or sertraline administration reversed the changes in behavioral test and induced the expression of tPA in certain brain areas, but failed to restore the CUMS-induced PAI-1 expression. Meanwhile, the antidepressant treatment also accelerated the extracellular conversion of proBDNF into mature BDNF in CUMS rats. Our results firstly showed the synchronously altered balance of tPA/PAI-1 system in the prefrontal cortex and hippocampus of CUMS rats, which was partly ameliorated by PUFAs and sertraline medication, providing new evidence for the involvement of tPA/PAI-1 system in the progression and treatment of depression.

Long Chain Omega-3 Polyunsaturated Fatty Acid Supplementation Alleviates Doxorubicin-Induced Depressive-Like Behaviors and Neurotoxicity in Rats: Involvement of Oxidative Stress and Neuroinflammation

Doxorubicin (DOX) is a chemotherapeutic agent widely used in human malignancies. Its long-term use can cause neurobiological side-effects associated with depression. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), the essential fatty acids found in fish oil, possess neuroprotecitve and antidepressant activities. Thus, the aim of this study was to explore the potential protective effects of ω-3 PUFAs against DOX-induced behavioral changes and neurotoxicity. ω-3 PUFAs were given daily by gavage (1.5 g/kg) over three weeks starting seven days before DOX administration (2.5 mg/kg). Open-field test (OFT) and forced swimming test (FST) were conducted to assess exploratory activity and despair behavior, respectively. Our data showed that ω-3 PUFAs supplementation significantly mitigated the behavioral changes induced by DOX. ω-3 PUFAs pretreatment also alleviated the DOX-induced neural apoptosis. Meanwhile, ω-3 PUFAs treatment ameliorated DOX-induced oxidative stress in the prefrontal cortex and hippocampus. Additionally, gene expression of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α, and the protein levels of NF-κB and iNOS were significantly increased in brain tissues of DOX-treated group, whereas ω-3 PUFAs supplementation significantly attenuated DOX-induced neuroinflammation. In conclusion, ω-3 PUFAs can effectively protect against DOX-induced depressive-like behaviors, and the mechanisms underlying the neuroprotective effect are potentially associated with its anti-oxidant, anti-inflammatory, and anti-apoptotic properties.

Abnormal plasma monoamine metabolism in schizophrenia and its correlation with clinical responses to risperidone treatment

Abnormalities in plasma monoamine metabolism reflect partly the illness of schizophrenia and sometimes the symptoms. Such studies have been repeatedly reported but have rarely taken both metabolites and parent amines or inter-amine activity ratios into account. In this study, the monoamines, their metabolites, turnovers and between-metabolite ratios in plasma were measured longitudinally in 32 schizophrenic patients treated with risperidone for 6 weeks, to examine possible biochemical alterations in schizophrenia, and to examine the association between treatment responses and psychopathology assessed according to the Positive and Negative Syndrome Scale (PANSS). The results showed lower level of plasma 3,4-dihydroxyphenylacetic acid (DOPAC) in relapsed versus first-episode schizophrenic patients, higher norepinephrine (NE) turnover rate (TR) in undifferentiated in comparison to paranoid schizophrenic patients and relatively higher metabolic activity of dopamine (DA) to serotonin (5-HT) in first-episode versus relapsed schizophrenic patients. Risperidone treatment induced a decrement of plasma DA levels and increments of plasma DOPAC and DA TR in the total group of schizophrenic patients. The turnover rate of 5-HT was was reduced in undifferentiated and relapsed subgroups of schizophrenic patients. The linkages between 5-HT TR, DA/NE relative activity and clinical symptomatology were also identified. These findings are consistent with an involvement of these systems in the pathogenesis of schizophrenia as well as in the responses to treatment, and the usefulness of certain biochemical indices as markers for subgrouping.