[Simultaneous determination of 11 neurotransmitters in brain microdialysis samples from rats by UPLC-MS/MS].

This study established a method for simultaneous determination of 11 neurotransmitters, such as acetylcholine, glutamic acid, glycine, and norepinephrine from rat brain microdialysis samples using UPLC-MS/MS. A total of 20 µL of rat brain dialysate was diluted with 60 µL of acetonitrile-water(4∶1) and centrifuged for 10 min at 10 000 r·min~(-1),and 5 µL was injected into UPLC-MS/MS system for assay. Chromatographic separation was performed on a Waters ACQUITY BEH amide column(2.1 mm×100 mm, 1.7 µm) with gradient elution using acetonitrile/0.2% formic acid-water as mobile phases with a flow rate of 0.35 mL·min~(-1) and column temperature of 35 ℃. The eluate was detected by multiple-reaction monitoring(MRM) scanning with an electrospray ionization source operating in the positive ionization mode with an analysis duration of 3.5 min. The relationship between the recovery rate of 11 neurotransmitters and the perfusion rate or the concentration of neurotransmitters was investigated. Furthermore, the effects of puerarin alone or combined with borneol on the content of 11 neurotransmitters in the striatum of rats were investigated. The results showed the calibration curves displayed good linear regression with coefficients all greater than 0.99 and the lower limit of quantification(LLOQ) less than 12.5 nmol·L~(-1) for each analyte. The within-run and between-run precision(RSD) of the 11 neurotransmitters at low, medium, and high levels was less than 9.3%, and the relative error of the accuracy ranged from-8.4% to 9.5%. The stability, recovery, and matrix effects were in line with the biological sample analysis requirements. As revealed by experimental results, the levels of most neurotransmitters in the brain striatum changed significantly after rats were treated with puerarin as compared with the conditions in the blank group. Except for dopamine and norepinephrine, the degree of changes of other neurotransmitters in the combination group(borneol and puerarin) was less than that of the puerarin group. The established UPLC-MS/MS method could be applied to the quantitative determination of 11 neurotransmitters in microdialysis samples, providing an efficient and useful tool to study neurotransmitter changes in animal models of health and diseases.

[Analysis of metabolites of 4,5-dicaffeoylquinic acid in rat plasma and urine based on LC-MS].

Ultra high performance liquid chromatography tandem high field orbital trap mass spectrometry(UPLC-Orbitrap Elite-MS/MS) method was applied in this paper to analyze the metabolites of 4,5-dicaffeoylquinic acid in rat plasma and urine after oral administration. A gradient elution was performed by using Thermo C_(18) column(2.1 mm×100 mm, 1.9 µm), with 0.1% formic acid solution-acetonitrile as the mobile phase. Mass spectral data of biological samples were collected in negative ion mode. The data were extracted by Compound Discovery 2.1 software. Then the blank group samples and the drug samples were compared for exact molecular weight and the mass fragmentation information, and the secondary fragment fitting ratio was calculated to finally attribute the metabolites. As a result, 15 metabolites were detected in rat plasma, and 16 metabolites were detected in urine. The involving metabolic reactions included methylation, hydration, dehydration, reduction, glucuronide conjugation, and sulfation reaction. The metabolites in plasma and urine complemented each other and initially revealed the migration and excretion patterns of this compound in the body. A method for pre-processing biological samples, high-resolution LC-MS instrumentation data, and qualitative software was established in this study to identify metabolite structures, laying the foundation for the study of the active ingredients and in vivo pharmacodynamics forms of Chinese medicines.

Prognostic value of immune checkpoint molecules in head and neck cancer: a meta-analysis.

Immune checkpoint molecules are important targets in cancer immunotherapy, but their association with prognosis in patients with head and neck cancer is controversial. In this meta-analysis, we searched for 12 immune checkpoint molecules in the PubMed, Embase and Cochrane Library databases and retrieved 52 studies with 7127 participants. Among the molecules included in the search, indoleamine 2, 3-dioxygenase (IDO), programmed death ligand 1 (PD-L1), and programmed death 1 (PD-1) met the inclusion criteria for further analysis. Higher expression of IDO was associated with poorer overall survival in head and neck cancer patients (P = 0.011), but higher expression of PD-L1 correlated with better overall survival specifically in nasopharyngeal carcinoma patients (P = 0.01). In a sensitivity analysis, higher PD-L1 expression correlated with better progression-free survival (P = 0.043), and was associated with better overall survival in Caucasian subjects (P = 0.02), nasopharyngeal carcinoma patients (P = 0.015), and studies with small sample sizes (P = 0.001). PD-1 had no prognostic significance. There was no publication bias affecting the results. Thus, among the immune checkpoint molecules, IDO and PD-L1 are potential prognostic predictors in head and neck cancer.

Naturally occurring proteinaceous nanoparticles in Coptidis Rhizoma extract act as concentration-dependent carriers that facilitate berberine absorption.

Pharmacological activities of some natural products diminish and even disappear after purification. In this study, we explored the mechanisms underlying the decrease of acute oral toxicity of Coptidis Rhizoma extract after purification. The water solubility, in vitro absorption, and plasma exposure of berberine (the major active compound) in the Coptidis Rhizoma extract were much better than those of pure berberine. Scanning electron microscopy, laser scanning confocal microscopy (LSCM), and dynamic light scattering experiments confirmed that nanoparticles attached to very fine precipitates existed in the aqueous extract solution. The LSCM experiment showed that the precipitates were absorbed with the particles by the mouse intestine. High-speed centrifugation of the extract could not remove the nanoparticles and did not influence plasma exposure or acute oral toxicity. However, after extract dilution, the attached precipitates vanished, although the nanoparticles were preserved, and there were no differences in the acute oral toxicity and plasma exposure between the extract and pure berberine. The nanoparticles were then purified and identified as proteinaceous. Furthermore, they could absorb co-dissolved berberine. Our results indicate that naturally occurring proteinaceous nanoparticles in Coptidis Rhizoma extract act as concentration-dependent carriers that facilitate berberine absorption. These findings should inspire related studies in other natural products.

Long-term effect of early postnatal overnutrition on insulin resistance and serum fatty acid profiles in male rats.

BACKGROUND: Increasing evidence suggests that overnutrition during the early postnatal period, a critical window of development, increases the risk of adult-onset obesity and insulin resistance. In this study, we investigated the impact of overnutrition during the suckling period on body weight, serum biochemistry and serum fatty acid metabolomics in male rats. METHODS: Rats raised in small litters (SL, 3 pups/dam) and normal litters (NL, 10 pups/dam) were used to model early postnatal overnutrition and control, respectively. Serum glucose, triglyceride, high-density lipoprotein-cholesterol, free fatty acid, insulin and leptin concentrations were assayed using standard biochemical techniques. Serum fatty acids were identified and quantified using a gas chromatography-mass spectrometry-based metabolomic approach. mRNA and protein levels of key components of the insulin receptor signaling pathway were measured in epididymal fat and gastrocnemius muscle by quantitative PCR and western blotting. RESULTS: SL rats were 37.3 % and 15.1 % heavier than NL rats at weaning and 16-weeks-old, respectively. They had increased visceral fat mass, adult-onset insulin resistance and glucose intolerance as well as elevated serum levels of free fatty acids and triglycerides. All detectable fatty acids were elevated in the serum of SL pups at weaning compared to NL controls, and significant increases in the levels of four fatty acids (palmitic acid, palmitoleic acid, oleic acid and arachidonic acid) persisted into adulthood. Moreover, a significantly positive correlation was identified between an insulin resistance index (HOMA-IR) and concentrations of myristic, palmitic, palmitoleic and oleic acid in serum at postnatal 16 weeks. Early postnatal overnutrition also resulted in a significant downregulation of insulin receptor substrate-1 (Irs-1), protein kinase B (Akt2) and glucose transporter 4 (Glut4) at the protein level in epididymal fat of SL rats at 16 weeks, accompanied by decreased mRNA levels for Irs-1 and Glut4. In gastrocnemius muscle, Akt2 and Glut4 mRNA and Glut4 protein levels were significantly decreased in SL rats. CONCLUSIONS: This study demonstrates that early postnatal overnutrition can have long-lasting effects on body weight and serum fatty acid profiles and can lead to impaired insulin signaling pathway in visceral white adipose tissue and skeletal muscle, which may play a major role in IR.

Identification and pharmacokinetics of multiple constituents in rat plasma after oral administration of Yinchenzhufu decoction.

ETHNOPHARMACOLOGICAL RELEVANCE: Yinchenzhufu decoction (YCZFD) is a classical Chinese herbal formula and has been used to treat severe jaundice in chronic liver injuries since the Qing Dynasty (18th century CE). To identify the components absorbed into the blood in YCZFD and explore their pharmacokinetic profile for understanding the effective ingredients of YCZFD. MATERIALS AND METHODS: After rats were given YCZFD by intragastric administration, the plasma was processed by precipitation of protein. The compounds in YCZFD extract and the plasma were identified by using high-resolution mass spectrometry with a database-directed strategy. The pharmacokinetics of multiple compounds from YCZFD in rat plasma was studied by using the established UPLC-MS/MS method. RESULTS: Forty compounds in YCZFD extract and 21 prototype compounds with 11 metabolites in rat plasma were detected after oral administration. The pharmacokinetic parameters of glycyrrhizic acid, glycyrrhetic acid, cinnamic acid, ononin, atractylenolide III, and liquiritin from YCZFD were obtained in rats. CONCLUSIONS: The identified constituents and the pharmacokinetic features of YCZFD are helpful for understanding the material bases of its therapeutic effects.