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OBJECTIVE To investigate the effect of hypoxia on the pharmacokinetic process of salidrosidein rats and to explore its underlying mechanisms. METHODS The Caco-2 cell monolayerwas exposed to 1% oxygen (O2) concentration for 24 h to build the hypoxiccell model. The transportation mode of salidroside was investigated with the aid of this hypoxia model by detecting the apparent permeability coefficient(Papp). Healthy Sprague Dawley (SD) rats were exposed to 9% O2 for 72 h for the construction of hypoxic rat model. Liver sample was subsequently collected from the hypoxic rats with an aim to identify enzymes responsible for salidroside metabolism. The expression levels of sali?droside-transporting and salidroside-metabolizing enzymes, including Sodium-dependent glucose cotrans?porters (SGLT1), β-glucosidase (GBA3)and sulfotransferase (SULT2A1), were thereafter detected by RT-PCR and Western blot. The metabolic activity of GBA3 and SULT2A1 was monitored by rat liver microsome incubation.In addition, the renal function of rats under hypoxia was assessed by detecting concentrations of blood urea nitrogen and creatinine. RESULTS The AUC and t1/2 values of salidroside in hypoxic rats were more than doubled, while the in vivo clearance was significantly reduced. Mechanistic study demonstrated that the PappA- B/PappB- A eualsto 10.3, indicating the potential active transport of salidrosile. The expression of SGLT1 and GBA3 was significantly decreased, which indicated a reduced metabolism of salidroside under hypoxia. Moreover, rat under hypoxia was found to suffer from renal dysfunction, with an abnormal value of blood urea nitrogen. CONCLUSION Due to the reduced metabolism and the abnormal renal function under hypoxia, the systemic exposure of salidroside in rats was signifi?cantly enhanced.
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OBJECTIVE Lapachol is a natural naphthoquinone compound that possesses extensive biological activities. The aim of this study is to investigate the inhibitory effects of lapachol on rat C6 glioma both in vitro and in vivo, as well as the potential mechanisms. METHODS The antitumor effect of lapachol was firstly evaluated in the C6 glioma model in Wistar rats. The effects of lapachol on C6 cell proliferation, apoptosis and DNA damage were detected by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS)/ phenazinemethosulfate (PMS) assay, hoechst 33358 staining, annexinⅤ-FITC/PI staining, and comet assay. Effects of lapachol on topoisomerase I (TOP I) and topoi?somerase Ⅱ (TOP Ⅱ) activities were detected by TOP Ⅰ and TOP Ⅱ mediated supercoiled pBR322 DNA relaxation assays and molecular docking. TOPⅠ and TOPⅡ expression levels in C6 cells were also determined. RESULTS High dose lapachol showed significant inhibitory effect on the C6 glioma in Wistar rats (P<0.05). It was showed that lapachol could inhibit proliferation, induce apoptosis and DNA damage of C6 cells in dose dependent manners. Lapachol could inhibit the activities of both TOPⅠ and Ⅱ. Lapachol-TOPⅠ showed relatively stronger interaction than that of lapachol-TOPⅡ in molecular docking study. Also, lapachol could inhibit TOPⅡ expression levels, but not TOPⅠ expression levels. CONCLUSION These results showed that lapachol could significantly inhibit C6 glioma both in vivo and in vitro, which might be related with inhibiting TOPⅠ and TOPⅡ activities, as well as TOPⅡ expression.
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OBJECTIVE To map a comprehensive metabolic pathway of herbacetin in rats, specifically, to elucidate the biotransformation of herbacetin in vivo and to simultaneously monitor the pharmacokinetic process of both parent drug and its major metabolites. METHODS liquid chromatography/ion trap mass spectrometry (LC/MSn) and ultra-liquid chromatography coupled with mass spectrometry (UPLC/MS) were combined in the current study for qualitative and quantitative determinations of herbacetin and its metabolites in bile, urine and feces after both oral and intravenous administration of herbacetin to rats. Enzyme kinetic studies on the intestinal and hepatic metabolism of herbacetin were further conducted to elucidate metabolic profiles of herbacetin in rat tissues and organs. Additionally, plasma concentration profiles of herbacetin and its metabolites in rats were obtained to characterize the overall pharmacokinetic behavior of herbacetin. RESULTS It was found that herbacetin was excreted primarily from rat urine in the form of glucuronide-conjugations. Subsequent in vitro enzyme kinetic studies and in vivo pharmacokinetic investigations suggested an extensive hepatic metabolism of herbacetin and the high exposure of herbacetin- glucuronides in systemic circulation. The clearance, half- life and bioavailability of herbacetin in rats were determined as (16.4±1.92)mL·kg-1·min-1, (11.9±2.7)min, and 1.32%, respectively. On basis of these findings, a comprehensive metabolic pathway of herbacetin in rats was composed. In addition, a physiology based pharmacokinetic (PBPK) model was successfully developed with the aid of the GastroPlus to simulate the pharmacokinetic process of herbacetin in rats. Application of the PBPK modeling can provide a useful starting point to understand and extrapolate pharmacokinetic parameters among different species, populations, and disease states. CONCLUSION After oral administration, herbacetin was subjected to colonic degradation and extensive first pass metabolism, with glucuronidation as its dominating in vivo metabolic pathway.
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OBJECTIVE The aim of the study was to characterize the pharmacokinetics (PK) and pharmacodynamics (PD) profile of cisatracurium in 0-2 years and 2-5 years old children patients with cheilopalatognathus, to find if there are some connections between the different muscle relaxation action and different PK procedure . METHODS 14 children patients were divided into two groups, ≤2 years and 2-5 years group, venous samples were taken before injection of a 0.15 mg·kg- 1 dose of cisatracurium and then at 2, 5, 10, 30, 60, 90, and 120 min. Cisatracurium plasma concentrations were determined by ultra- performance liquid chromatography/electrospray ionization/triple quadrupole tandem mass spectrometer system (UPLC/MS/MS). The degree of neuromuscular block was measured by train of four (TOF) testing. An indirect PK-PD link model with a sigmoid Emax model was established using Win Nonlin software. The model were applied to PK and PD data analysis, respectively. RESULTS The TOF monitor parameters showed that cisatracurium works very quickly, the onset time were (2.64± 0.93) min and (2.59 ± 0.90) min for ≤2 years and 2- 5 years group respectively. Young children ≤2 years have longer muscle blocking duration time (62.5 ± 6.01 min vs 53.86 ± 12.18 min) and slower recovery index (32.14±7.10 min and 27.43±10.63 min) than those children in group of 2-5 years. More children ≤2 years have postoperative complication than that in 2-5 children. PK parameters showed that there were no statistical differences in blood concentration and pharmacokinetic parameters. While the concentration of cisatracurium in muscle site calculated by using PK/PD model were higher and longer for ≤2 year children than that of 2-5 year children. This means that cisatracurium could stay at high concentration for a longer time in younger children' muscle tissue. CONCLUSION As a result young children tend to have postoperative complications related to slower muscle recovery action and increased concentration in skeletal muscle. So more careful observation and monitor are needed for younger children, our study could be of use in clinical practice for the administration of cisatracurium to children patients.
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OBJECTIVE Hypoxia is associated with many complicated pathophysiological and biochemical processes that integrated and regulated via the key gene, protein and endogenous metabolite levels. Up to date, the exact molecular mechanism of hypoxia still remains unclear. In this work, we further explore the molecular mechanism of hypoxia and adaption to attenuate the damage in zebrafish model that have potential to resist hypoxic environment. METHODS The hypoxic zebrafish model was established in different concentration of oxygen with 3%,5%,10%,21% in water. The brain tissue was separated and the RNA-seq was used to identify the differentially expressed genes. The related endogenous metabolites profiles were obtained by LC-HDMS, and the multivariate statistics was applied to discover the important metabolites candidates in hypoxic zebrafish. The candidates were searched in HMDB, KEGG and Lipid Maps databases. RESULTS The zebrafish hypoxic model was successfully constructed via the different concentration of oxygen, temperature and hypoxic time. The activities of the related hypoxic metabolic enzymes and factors including HIF-1a, actate dehydrogenase (LDH) and citrate synthase (CS) were evaluated. Significant differences (P<0.05 and fold change >2) in the expression of 422 genes were observed between the normal and 3% hypoxic model. Among them, 201 genes increased depended on the lower concentration of oxygen. 53 metabolites were identified that had significant difference between the hypoxia and control groups (P<0.05, fold change>1.5 and VIP>1.5). The ten key metabolites were increased gradually while six compounds were decreased. The endogenous hypoxic metabolites of phenylalanine, D-glucosamine-6P and several important lipids with the relevant hub genes had similar change in hypoxic model. In addition, the metabolic pathways of phenylalanine, glutamine and glycolipid were influenced in both the levels of genes and metabolites. CONCLUSION The up- regulation of phenylalanine, D- glucosamine- 6P and lipid may have further understanding of protective effect in hypoxia. Our data provided an insight to further reveal the hypoxia and adaptation mechanism.