Liver metabolomic characterization of Sophora flavescens alcohol extract-induced hepatotoxicity in rats through UPLC/LTQ-Orbitrap mass spectrometry.

This study aimed to observe the influence of Sophora flavescens alcohol extract (SFAE) on hepatic metabolic profiling in rats to explore the possible mechanism of hepatotoxicity induced by S. flavescens.Male Sprague-Dawley rats were randomly divided into three groups (n = 6 in each group) and administered with SFAE at different doses of 0, 1.25 and 2.5 g/kg for two weeks. Ultra-performance liquid chromatography-high resolution mass spectrometry was utilized to detect the change in the metabolites in rat liver. Principal component analysis and orthogonal partial least squares discriminant analysis were adapted to perform multivariate statistical analysis between groups and to screen the potential biomarkers. Related metabolic pathway analysis was also conducted.Results indicated that hepatic metabolites in the three groups were separated on day 14, and 25 major differential metabolites were identified. Six bile acids, four carnitines, four lysophosphatidylcholines and glutathione were closely related to hepatotoxicity. Liver metabolomic results showed that rats orally exposed to SFAE exhibited a disturbance of the metabolism of bile acids, fatty acids, glycerophospholipids and amino acids.This study provided new insights into the possible mechanism of hepatotoxicity induced by SFAE in rats.

A selective sphingomyelin synthase 2 inhibitor ameliorates diet induced insulin resistance via the IRS-1/Akt/GSK-3ß signaling pathway.

Insulin resistance is a typical precursor and primary feature of type 2 diabetes mellitus (T2DM). Sphingomyelin (SM) is a kind of sphingolipid located in animal brain, liver, kidney and muscle. Sphingomyelin synthase 2 (SMS2) is the key enzyme in the synthesis of sphingomyelin, inhibition of which shows protective effects on cardiovascular and glucose metabolism. We used Ly93, a selective sphingomyelin synthase 2 inhibitor, to investigate the effect of SMS2 inhibitor on insulin resistance in vitro and in vivo. Our previous studies have shown that Ly93 is able to dose-dependently inhibit the SMS activity and attenuate the atherosclerotic lesions in apoE knock out mice. In this present study, we found that high fat diet (HFD) induced insulin-resistant C57BL/6 mice treated with Ly93 were more sensitive to insulin than untreated mice, and presented lower blood insulin levels and improved insulin tolerance. Furthermore, insulin signal pathway related protein levels were detected by western blot, which indicated that SMS2 inhibitor significantly upregulated the phosphorylation of IRS-1, Akt and GSK-3ß, thus enhanced the insulin signaling. In vitro, Ly93 enhanced the phosphorylation of Akt in HepG2 cells, which was reversed by exogenous sphingomyelin. These results suggest that SMS2 inhibitor could ameliorate insulin resistance via regulating the insulin signaling. Our findings support that SMS2 is a potential target for insulin resistance.

Hepatotoxicity Induced by Sophora flavescens and Hepatic Accumulation of Kurarinone, a Major Hepatotoxic Constituent of Sophora flavescens in Rats.

Our previous study showed that kurarinone was the main hepatotoxic ingredient of Sophora flavescens, accumulating in the liver. This study characterized the mechanism of Sophora flavescens extract (ESF) hepatotoxicity and hepatic accumulation of kurarinone. ESF impaired hepatic function and caused fat accumulation in the liver after oral administration (1.25 and 2.5 g/kg for 14 days in rats). Serum metabolomics evaluation based on high-resolution mass spectrometry was conducted and real-time PCR was used to determine the expression levels of CPT-1, CPT-2, PPAR-α, and LCAD genes. Effects of kurarinone on triglyceride levels were evaluated in HL-7702 cells. Tissue distribution of kurarinone and kurarinone glucuronides was analyzed in rats receiving ESF (2.5 g/kg). Active uptake of kurarinone and kurarinone glucuronides was studied in OAT2-, OATP1B1-, OATP2B1-, and OATP1B3-transfected HEK293 cells. Our results revealed that after oral administration of ESF in rats, kurarinone glucuronides were actively transported into hepatocytes by OATP1B3 and hydrolyzed into kurarinone, which inhibited fatty acid ß-oxidation through the reduction of l-carnitine and the inhibition of PPAR-α pathway, ultimately leading to lipid accumulation and liver injury. These findings contribute to understanding hepatotoxicity of kurarinone after oral administration of ESF.

Metabolism of kurarinone by human liver microsomes and its effect on cytotoxicity.

CONTEXT: Kurarinone, the most abundant prenylated flavonoid in Sophora flavescens Aiton (Leguminosae), is a promising antitumor therapeutic. However, it shows significant hepatotoxicity. Furthermore, how kurarinone is metabolized in humans remains unclear. OBJECTIVE: The objective of this study is to investigate kurarinone metabolism in human liver microsomes (HLMs) and the role of metabolism in kurarinone-induced cytotoxicity. MATERIALS AND METHODS: The UDP-glucuronosyltransferase isoforms (UGTs) involved in kurarinone glucuronidation were identified using chemical inhibitors (100-1000 µM phenylbutazone; 10-100 µM ß-estradiol; 10-100 µM 1-naphthol; 10-500 µM propofol; and 100-1000 µM fluconazole) and recombinant human UGTs. Kurarinone (2-500 µM) was incubated with HLMs and UGTs (0.5 mg/mL) for 15 min to determine enzyme kinetic parameters. The IC50 value of kurarinone (10-200 µM) was evaluated in a HLMs/3T3 cell co-culture system. RESULTS: Kurarinone is extensively converted to two glucuronides (M3 and M4) in HLMs. M3 formation was catalyzed by multiple UGT1As, with UGT1A3 showing the highest intrinsic clearance (120.60 mL/min/mg). M4 formation was catalyzed by UGT1A1, UGT2B4, and UGT2B7. UGT1A1 showed the highest intrinsic clearance (60.61 mL/min/mg). The kinetic profiles of the five main UGTs and HLMs fit substrate inhibition kinetics, with Km values ranging from 5.20 to 46.52 µM, Vmax values ranging from 0.20 to 3.06 µmol/min/mg, and Ksi values ranging from 25.58 to 230.30 µM. The kurarinone IC50 value was 93 µM in the control group, 102 µM in HLMs with NADPH, and 160 µM in HLMs with UDPGA. DISCUSSION AND CONCLUSION: Kurarinone glucuronidation is a detoxification pathway. This information may help to elucidate the risk factors regulating kurarinone toxicity.

[Proteomic study on effect of tangcao pill on microsome CYP450].

Tangcao pill is commonly applied in adjuvant and even alternative therapy for patients with AIDS. However, the herb contains complex ingredients, but with unknown effect against anti-HIV drug and unknown function. Because CYP450 emzyme is the main metabolic enzymes of the drug, it is of important significance to study the regulation of CYP450 enzymes before and after the combined administration of Tangcao pill and EFV. Proteomics, due to its high throughout and high sensitivity, has been widely applied in CYP450 enzyme study. In this paper, liver microsomes were separated through differential centrifugation. Their proteins were separated through SDS-PAGE. The three protein bands that CYP450 enzymes were located were cut and identified by liquid chromatography tandem mass spectrometry. Totally 16 CYP450 isoenzymes were identified. Furthermore, in order to make a quantitative analysis on the effect of tang herb on CYP450 emzyme, the multiple reaction monitoring (MRM) technology based on MS was adopted. The CYP2C11 was selected based on the results of the mass spectrum identification of proteins. The characteristic polypeptides were obtained through searching Expasy blast database. The m/z of the fragment ions was less than 800. In the paper, the m/z of ion pairs of CYP2C11 were 711.5/232.1, 711.5/319.2, 711.5/466.2 and 711.5/595.3, and the m/z of ESAT-6 (internal standard, IS) were 735.5/215.3, 735.5/389.3, 735.5/460.3 and 735.5/524.3. The relative peak (analyte/IS) area was adopted for the relative quantitative analysis. Compared with the EFV single administration group, the EFV and Tangcao pill combined administration group showed a 1.6-fold increase in CYP2C11. The results of the paper indicated that Tangcao pill may affect drug metabolism by regulating metabolic enzymes such as CYP2C11, but the specific mechanism still unknown.

CYP450 1A2 and multiple UGT1A isoforms are responsible for jatrorrhizine metabolism in human liver microsomes.

Jatrorrhizine, one of the protoberberine alkaloids derived from the plant Coptis chinensis, is expected to be developed as a new gastric prokinetic drug, but its metabolic characteristics in humans remain unknown. This study characterized the phase I and phase II metabolites, metabolic kinetics, and cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes responsible for the metabolism of jatrorrhizine in human liver microsomes (HLMs). Chemical inhibition in HLMs and metabolism by recombinant human CYP or UGT enzymes were employed to determine the key metabolic enzyme subtypes. In HLMs, demethyleneberberine (demethylated product) and jatrorrhizine glucuronide were identified as the phase I and phase II metabolites, respectively. The enzyme kinetics for both demethylation and glucuronidation were fitted to the Michaelis-Menten equation. Demethylation was inhibited significantly by furafylline and predominantly catalysed by recombinant CYP1A2, whereas glucuronidation was inhibited by silibinin, quercetin, as well as 1-naphthol and catalysed by recombinant UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9 and UGT1A10. These results showed that jatrorrhizine is metabolized by human CYP1A2 and multiple UGT1A isoforms.

Pharmacokinetics and metabolism of jatrorrhizine, a gastric prokinetic drug candidate.

Jatrorrhizine, a protoberberine alkaloid derived from Coptis chinensis, is currently under investigation as a natural gastric prokinetic drug candidate. In vitro and in vivo studies were conducted to characterize its pharmacokinetics and metabolism. After intravenous administration, the plasma concentration kinetics and major metabolites in rats were investigated. The metabolic kinetics, key cytochrome P450 enzymes and UDP-glucuronosyltransferase isoforms (UGTs) of jatrorrhizine were studied in rat liver microsomes (RLMs). After intravenous administration, plasma jatrorrhizine concentrations showed a biphasic decline, dose-independent clearance and half-life of terminal elimination phase, and a relatively large distribution volume. The metabolic pathway for the conversion of jatrorrhizine was important for its elimination. In addition, the demethylated and glucuronidated products were found to be the major metabolites in rats. The enzyme kinetics for both demethylation and glucuronidation were fitted to the hyperbolic Michaelis-Menten equation in RLMs. CYP3A1/2 and CYP2D2 were mainly responsible for demethylation, and UGT 1A1 and 1A3 were responsible for glucuronidation in RLMs. The metabolic properties of jatrorrhizine suggest multiple metabolic pathways. These results will contribute to promote further research and development of jatrorrhizine.

Overexpression of REST Causes Neuronal Injury and Decreases Cofilin Phosphorylation in Mice.

BACKGROUND: RE1-silencing transcription factor (REST) is known to silence target genes involved in synaptic plasticity and neuronal differentiation. Although previous studies implicate REST in neurodegenerative diseases, its function in the progression of Alzheimer's disease (AD) is uncertain. OBJECTIVE: The aim of the present work was to explore the mechanisms of AD and determine whether and how REST was involved in the pathogenesis of AD. METHODS: We investigated the differentially expressed genes and key transcription factors in AD using bioinformatics analysis. In addition, we assessed the expression of REST under the influence of AD-related factors. Mice overexpressing REST were generated and analyzed by proteomics analysis. We used transmission electron microscopy, Golgi-cox staining, immunohistochemistry, and western blotting to examine the impact of REST on neurons. RESULTS: The results of bioinformatics analysis revealed REST as a hub transcriptional regulator in AD. We demonstrate that the mRNA expression of REST was significantly upregulated compared with that in the control groups, not only in AD patients but also in APP/PS1 transgenic mice, lipopolysaccharide-induced neuroinflammatory mice, and oxidative and glutamate stressed neurons. Using proteomics analysis, we showed that the upregulation of REST increased the expression of genes involved in apoptotic and mitochondrial pathways. Long-term overexpression of REST significantly reduced the number of dendritic spines and increased the mitochondrial defect and apoptosis. Reduction of the cofilin phosphorylation may be one of its mechanisms, and cofilin activity could be affected through the P38 MAPK/CREB signaling pathway. CONCLUSION: These results demonstrated the possible mechanism underlying AD and indicated REST as a potential therapeutic target for AD.

Simultaneous quantification of multiple active components from Xiexin decoction in rat plasma by LC-ESI-MS/MS: application in pharmacokinetics.

A sensitive and specific liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-ESI-MS/MS) method was developed and validated to simultaneously quantify 11 active compounds (coptisine, jatrorrhizine, berberine, palmatine, baicalin, baicalein, wogonoside, wogonin, rhein, emodin and aloeemodin) from Xiexin decoction (XXD) in rat plasma. Plasma samples extracted by a single-step protein precipitation procedure were separated using the gradient mode on a Dikma ODS-C18 column. Selected reaction monitoring scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. Calibration curves offered satisfactory linearity (r > 0.995) at linear range of 0.47-60 ng/mL for coptisine, jatrorrhizine, berberine and palmatine, 15-1930 ng/mL for baicalin, 20-2560 ng/mL for baicalein, 14-1790 ng/mL for wogonoside, 0.57-72.8 ng/mL for wogonin, 10-1280 ng/mL for rhein, 0.6-76.8 ng/mL for emodin and 3.0-384 ng/mL for aloeemodin. The intra- and interday precisions were less than 10.2% in terms of relative standard deviation (RSD), and the accuracies were within ±10.84% in terms of relative error (RE). It was successfully applied to the evaluation of pharmacokinetics after single oral doses of XXD were administered to rats.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects.

BACKGROUND AND OBJECTIVES: Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K+ of the H+, K+-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects. METHODS: Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms. RESULTS: No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (Tmax) at 0.5 h and declined with a terminal (elimination) half-life (t1/2) of 3.87-4.57 h. The maximum measured plasma concentration (Cmax) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the corresponding area under the concentration-time curve (AUC) from time zero to infinity (AUC0-inf) was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of Cmax and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender. CONCLUSIONS: Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mg in multiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

[Dual effects of extract of Schisandra chinensis Baill on rat hepatic CYP3A].

This study is to investigate the effects of aqueous extract of Schisandra chinensis Baill (WWZ), kadsurin, schisandrin A, schisandrin B and schisandrol B on rat hepatic CYP3A. Rats received a daily gavage of aqueous extract of WWZ for different times. The livers were harvested after gavage and subjected to microsome preparation. Microsomal CYP3A activity was determined by measuring the amount of the metabolite of testosterone (6 beta-hydroxytestosterone) with HPLC. Aqueous extract of WWZ, kadsurin and schisandrin A were incubated with microsomes obtained from rat. Microsomal CYP3A activity was determined by HPLC. Primary hepatocytes were separated and extracted from rat, then were treated with aqueous extract of WWZ, schisandrin A, schisandrin B and schisandrol B. Then, the expression of CYP3A1 mRNA was analyzed by RT-PCR. As for the in vivo assay, aqueous extract of WWZ significantly inhibited the enzyme activity of CYP3A after 12 h gavage. The inhibitory effect was converted to inductive effect after 3-day gavage. Aqueous extract of WWZ could induce the enzyme activity of CYP3A after 6-day gavage. Aqueous extract of WWZ and kadsurin showed a dose-dependent inhibition of CYP3A (IC50 of 487.8 microg mL(-1) and 6.2 micromol L(-1), separately). In rat primary hepatocytes, aqueous extract of WWZ (2.5 mg mL(-1)), schisandrin A (0.1 micromol L(-1)), schisandrin B (0.1 micromol L(-1)) and schisandrol B (10 micromol L(-1)) increased significantly the expression of CYP3A1 mRNA by 23%, 55%, 42% and 27%, respectively. Aqueous extract of WWZ could show dual effect on the enzyme activity of CYP3A in rat in vivo. Meanwhile, kadsurin showed a dose-dependent inhibition of the enzyme activity of hepatic CYP3A in vitro. And schisandrin A, schisandrin B and schisandrol B showed significant inductive effect on the expression of rat CYP3A1 mRNA.

Saikosaponin B2 attenuates kidney fibrosis via inhibiting the Hedgehog Pathway.

BACKGROUND: Renal interstitial fibrosis is a common pathway through which chronic kidney disease progresses to end-stage renal disease. There are currently no effective drugs available to treat kidney fibrosis, so traditional medicine is likely to be a candidate. The therapeutic potential of saikosaponin B2 (SSB2), a biologically active ingredient of Radix Bupleuri, on renal fibrosis has not been reported. METHODS: A unilateral ureteral obstruction (UUO) model was conducted to induce renal interstitial fibrosis in mice. SSB2's effect was valuated by histological staining and exploring the changes in expression of relative proteins and mRNAs. A conditional medium containing sonic hedgehog variant protein stimulating normal rat kidney interstitial fibroblast cells (NRK-49F) was used in an in vitro model to determine the possible mechanism. The molecular target of SSB2 was verified using several mutation plasmids. RESULTS: SSB2 administration reduced kidney injury and alleviated interstitial fibrosis by decreasing excessive accumulation of extracellular matrix components in UUO mice. It could also reduce the expression of α-SMA, fibronectin and Gli1, a crucial molecule of the hedgehog (Hh) signaling pathway both in vivo and in vitro. In NIH-3T3 cells simulated by conditional medium containing sonic hedgehog variant protein, SSB2 showed the ability to decrease the expression of Gli1 and Ptch1 mRNA. Using a dual-luciferase reporter assay, SSB2 suppressed the Gli-luciferase reporter activity in NIH-3T3 cells, and the IC50 was 0.49 µM, but had no effect on the TNF-α/NF-κB and Wnt/ß-catenin signaling pathways, indicating the inhibition selectivity on the Hh signaling pathway. Furthermore, SSB2 failed to inhibit the Hh pathway activity evoked by ectopic expression of Gli2ΔN and Smo D473H, suggesting that SSB2 might potentially act on smoothened receptors. CONCLUSION: SSB2 could attenuate renal fibrosis and decrease fibroblast activation by inhibiting the Hh signaling pathway.

Glutamate Activates the Histaminergic Tuberomammillary Nucleus and Increases Wakefulness in Rats.

Glutamate is the major excitatory neurotransmitter in the brain and plays an essential role in regulating wakefulness. Histaminergic neurons, which are exclusively localized in the tuberomammillary nucleus (TMN) of the hypothalamus, have a pivotal role in the regulation of sleep-wake patterns by sending widespread projections into many brain areas implicated in sleep-wake control. The role of glutamate in histaminergic neurons within the TMN and the resulting sleep-wake profile remains unknown. We found that glutamate, NMDA, AMPA or dihydrokainate, a glutamate-uptake inhibitor, dose-dependently increased wakefulness when microinjected into the rat TMN. Glutamate, NMDA, and AMPA also increased the firing rate of action potentials in TMN histaminergic neurons. The arousal-promoting effect of glutamate was inhibited by NMDA and histamine H1 receptor antagonists. Furthermore, MK-801, an NMDA receptor antagonist, inhibited the firing rate of histaminergic neurons and increased non-rapid eye movement sleep after microinjection into rat TMN. Taken together, these findings demonstrated that glutamate activated histaminergic neurons in the TMN and increased wakefulness in rats, possibly via the action of NMDA and histamine H1 receptors.

Discovery, synthesis and anti-atherosclerotic activities of a novel selective sphingomyelin synthase 2 inhibitor.

The sphingomyelin synthase 2 (SMS2) is a potential target for pharmacological intervention in atherosclerosis. However, so far, few selective SMS2 inhibitors and their pharmacological activities were reported. In this study, a class of 2-benzyloxybenzamides were discovered as novel SMS2 inhibitors through scaffold hopping and structural optimization. Among them, Ly93 as one of the most potent inhibitors exhibited IC50 values of 91 nM and 133.9 µM against purified SMS2 and SMS1 respectively. The selectivity ratio of Ly93 was more than 1400-fold for purified SMS2 over SMS1. The in vitro studies indicated that Ly93 not only dose-dependently diminished apoB secretion from Huh7 cells, but also significantly reduced the SMS activity and increased cholesterol efflux from macrophages. Meanwhile, Ly93 inhibited the secretion of LPS-mediated pro-inflammatory cytokine and chemokine in macrophages. The pharmacokinetic profiles of Ly93 performed on C57BL/6J mice demonstrated that Ly93 was orally efficacious. As a potent selective SMS2 inhibitor, Ly93 significantly decreased the plasma SM levels of C57BL/6J mice. Furthermore, Ly93 was capable of dose-dependently attenuating the atherosclerotic lesions in the root and the entire aorta as well as macrophage content in lesions, in apolipoprotein E gene knockout mice treated with Ly93. In conclusion, we discovered a novel selective SMS2 inhibitor Ly93 and demonstrated its anti-atherosclerotic activities in vivo. The preliminary molecular mechanism-of-action studies revealed its function in lipid homeostasis and inflammation process, which indicated that the selective inhibition of SMS2 would be a promising treatment for atherosclerosis.

Study of the process of secondary failure of sulphonylurea by a Markov model.

PURPOSE: The study was to reflect and forecast the evolutive tendency and influence factors of secondary failure of sulphonylurea (SFS) changing with time by using a Markov (MKV) model in the elderly diabetic population in Shanghai. METHODS: A total of 549 patients with elderly diabetes mellitus (DM) were enrolled and grouped in the study. A door-to-door retrospective epidemiological survey was used to collect data. The MKV model was used to assess the process and influence factors of SFS and the MKV process decision support system was adopted to calculate state probability of the MKV process. RESULTS: The rate of SFS in the group of all cases, FPG < or = 10 mmol . L(-1) before treatment and FPG > 10 mmol . L(-1) before treatment, taking single type of sulphonylurea (SU) and taking two types of SU and over respectively was 9.11%, 3.55%, 11.03%, 8.54% and 11.21%. The years of changing into the state of secondary failure in half patients was 5 years, 11-12 years, 4 years, 5 years, 4 years, respectively in the following groups: all cases, FPG < or = 10 mmol . L(-1) before treatment and FPG > 10 mmol . L(-1) before treatment, taking single type of SU and taking two types of SU and over. CONCLUSIONS: A MKV model could predict the long-term evolutive process of SFS by a short-term observation; the speed of SFS was related to the degree of DM patients' condition, patients with higher glucose levels prior to treatment would develop SFS faster; but we cannot postpone the development of secondary failure by exchanging SU types.

Increased secretion and expression of amylin in spontaneously diabetic Goto-Kakizaki rats treated with rhGLP-1 (7-36).

AIM: To investigate the effect of recombined human glucagon-like peptide 1 (rhGLP-1 [7-36]) on the secretion and expression of amylin in Goto-Kakizaki (GK) rats. METHODS: The GK rats were treated with rhGLP-1 (7-36) 56 and 133 mug/kg subcutaneously for 12 weeks. The fasting and post-prandial blood glucose levels were measured. The plasma amylin concentration was measured by ELISA. The transcription levels of amylin and insulin mRNA were evaluated by fluorescent-quantitative- PCR. Immunohistochemistry was utilized to detect the amylin protein. Histological examination was assayed by light microscopy. RESULTS: Treatment with rhGLP-1 (7-36) caused a significant reduction of post-prandial blood glucose levels in the GK rats (P<0.05). The plasma amylin levels of the GK rats were lower than those of Wistar rats after the glucose administration (P<0.01). Treatment with rhGLP-1 (7-36) exhibited a marked elevation of the glucose-stimulated plasma amylin level (P<0.05) and slight histological amelioration. The amylin expression was augmented in the rhGLP-1 (7-36)-treated GK rat pancreas. Amylin and insulin mRNA were also highly expressed in the treated GK rats (P<0.05). However, the ratio of amylin to insulin mRNA was significantly decreased by treatment with rhGLP-1 (7-36). CONCLUSION: RhGLP-1 (7-36) stimulates the secretion and expression of amylin, and exerts a beneficial effect on the ratio of amylin to insulin mRNA. These findings suggest that GLP-1 and GLP-1 analogs are ideal candidates for the treatment of type 2 diabetes.

Mechanism in the existent difference in form of wogonin/wogonoside between plasma and intestine/liver in rats.

Wogonin (WO) and its glucuronide, wogonoside (WG) exhibit various beneficial bioactivities that may have potential for the development of novel drugs. In this study, we determined their pharmacokinetic characteristics in rats after intragastric administration of WO and intraportal vein injection of WG. WG was the predominant form in the portal vein and body plasma, and in bile; WO was detected only in the small intestine and liver. WG is a substrate of the multidrug resistance-associated protein (MRP) 1, 2, 3, and 4, and organic anion-transporting polypeptide (OATP) 2B1 and OATP1B3. Metabolism studies indicated that WG formation and WO decrease had similar CLint values in rat intestine S9 (RIS9) and rat liver microsome (RLM), and that the hydrolysis rate of WG in RIS9 and rat liver S9 (RLS9) was fast. Thus, WG could be excreted into the intestinal tract by MRP2, and transported into mesenteric blood by MRP1, 3, and 4. OATP2B1 and OATP1B3 mediated the hepatic uptake of WG and MRPs mediated WG efflux to the bile and circulation. The high transport capability of MRPs for WG and the fast hydrolysis in the small intestine and liver may be responsible for the presence of WO in these tissues.

Changes in brain interleukin-1beta following the coadministration of norfloxacin with biphenylacetic acid in rats.

We sought to determine the changes in brain interleukin-1beta (IL-1beta) following the coadministration of norfloxacin (25 mg/kg, i.p.) with biphenylacetic acid (100 mg/kg, p.o.) in rats. Norfloxacin provoked clonic convulsions in rats treated concomitantly with biphenylacetic acid, a major metabolite of the nonsteroidal anti-inflammatory drug fenbufen. Seizure activity was analyzed by EEG monitoring. Behavioral changes were also monitored. IL-1beta expressions in the prefrontal cortex and hippocampus at different time intervals were studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The epileptiform discharges appeared in all the rats, accompanied with limb twitching and clonic-tonic seizures after administration of norfloxacin coadministered with biphenylacetic acid. Norfloxacin plus biphenylacetic acid-induced convulsions rapidly and transiently enhanced IL-1beta mRNA in the prefrontal cortex and hippocampus. IL-1beta mRNA expression in the prefrontal cortex and hippocampus was detected as soon as 30 min after norfloxacin injection, and decayed to control levels by 6 h. ELISA analysis revealed significant increase of the IL-1beta protein in the prefrontal cortex and hippocampus at 2 h and 6 h. Administration of either norfloxacin or biphenylacetic acid alone did not elicit convulsions and increase in IL-1beta mRNA and protein expressions. The results suggest that the increased IL-1beta expressions in the prefrontal cortex and hippocampus induced by norfloxacin with biphenylacetic acid relate to seizure activities, and that these brain regions play pivotal roles in norfloxacin-induced convulsions.

Paeoniflorin exerts analgesic and hypnotic effects via adenosine A1 receptors in a mouse neuropathic pain model.

RATIONAL: Neuropathic pain is frequently comorbid with sleep disturbances. Paeoniflorin, a main active compound of total glucosides of paeony, has been well documented to exhibit neuroprotective bioactivity. OBJECTIVE: The present study evaluated effects of paeoniflorin on neuropathic pain and associated insomnia and the mechanisms involved. METHODS: The analgesic and hypnotic effects of paeoniflorin were measured by mechanical threshold and thermal latency, electroencephalogram (EEG) and electromyogram, and c-Fos expression in a neuropathic pain insomnia model. RESULTS: The data revealed that paeoniflorin (50 or 100 mg/kg, i.p.) significantly increased the mechanical threshold and prolonged the thermal latency in partial sciatic nerve ligation (PSNL) mice. Meanwhile, paeoniflorin increased non-rapid eye movement (NREM) sleep amount and concomitantly decreased wakefulness time. However, pretreatment with l,3-dimethy-8-cyclopenthylxanthine, an adenosine A1 receptor (R, A1R) antagonist, abolished the analgesic and hypnotic effects of paeoniflorin. Moreover, paeoniflorin at 100 mg/kg failed to change mechanical threshold and thermal latency and NREM sleep in A1R knockout PSNL mice. Immunohistochemical study showed that paeoniflorin inhibited c-Fos overexpression induced by PSNL in the anterior cingulate cortex and ventrolateral periaqueductal gray. CONCLUSIONS: The present findings indicated that paeoniflorin exerted analgesic and hypnotic effects via adenosine A1Rs and might be of potential use in the treatment of neuropathic pain and associated insomnia.

Effect of pirenzepine ophthalmic solution on form-deprivation myopia in the guinea pigs.

BACKGROUND: Nonselective muscarinic receptor antagonist, atropine, was believed to inhibit myopic progression. The purpose of this study was to determine the efficacy, through topical administration, of the M1-selective muscarinic antagonist pirenzepine in preventing experimentally induced form-deprivation myopia in guinea pigs. METHODS: Fifty-three guinea pigs, which underwent monocular deprivation with their eyelids sutured, were divided into 6 groups. Three groups were treated with 1%, 2% or 4% pirenzepine ophthalmic solutions; the fourth group with atropine; the fifth with saline and the last group left untreated. Ocular refraction, in vivo biometric measurements and wet eye weight were collected before and after the experiment. All the eyes were finally enucleated for histopathological examination to evaluate the possible toxic effects on ocular structures. RESULTS: Animals untreated or treated with saline produced (-2.31+/-1.47) D and (-2.25+/-0.88) D of axial myopia respectively. Those treated with 1% pirenzepine ophthalmic solution produced relative myopia of (-1.63+/-0.48) D, and those under the treatment of 2% and 4% pirenzepine ophthalmic solution only developed a relative myopia of (-0.89+/-0.42) D and (-0.70+/-0.41) D (F=9.56, P<0.05). The significant reduction in myopia in 2% and 4% pirenzepine treated animals was caused by significantly less vitreous chamber elongation and axial elongation of the deprived eyes [2% group: (0.009+/-0.052) mm, 4% group: (0.006+/-0.078) mm] when compared with untreated, saline treated or 1% pirenzepine treated guinea pigs (0.057+/-0.056) mm, (0.064+/-0.053) mm and (0.033+/-0.035) mm, respectively]. Histological examinations revealed no obviously toxic effects on the eyes treated with pirenzepine. CONCLUSION: Topical administration of the M1-selective muscarinic antagonist, pirenzepine, can prevent induced form-deprivation myopia in guinea pigs by inhibiting axial elongation without obvious damage to ocular tissues.