Determination of trans-resveratrol in mouse liver by high performance liquid chromatography

To develop a sensitive high performance liquid chromatography （HPLC） assay for the determination of trans-resveratrol in mouse liver. The whole liver of a mouse was removed from the body, homogenated, and extracted by ethyl acetate. The organic layer was isolated and evaporated to dryness, the residue was reconstituted in 0.2 mL mobile phase for centrifugation, and 50 uL of the supernatant was injected into the/-IPLC instrument. The sample was separated on a Shimadzu ODS column （150 mm × 4.6 mm, 5 um） at 35 ℃ and detected by ultraviolet （UV） detector at the wavelength of 305 nm. The mobile phase consisted of methanol and 0.1 mol/L acetic acid （4：6, v/v） with the flow-rote at 1 mL/min. The limit of detection was 3.0 ng/g in liver homogenate with a signal/noise ratio of 3：1. The linear range of the calibration curve was 5.0-120.0 ng/g. The mean recoveries at the concentrations of 6, 10 and 80 ng/g were 102%, 96.0% and 91.5%, respectively. The RSDs for inter- and intra-day assays were less than 5%. Compared with other reported methods, this method was faster and more sensitive. It was also proved to be of good linearity, selectivity, accuracy and precision, and can be efficiently applied to the pharmacoldnetic study of trans-resveratrol in mouse liver.

Analysis of Proteotranscriptomics Landscape Reveals Differentially Regulated Pathways in Toxoplasma gondii Infected Mouse Liver

Toxoplasma gondii (T. gondii) an intracellular protozoan parasite, infects mammals including human population world-wide. Upon primary infection, the parasite contributes to mild flu like symptoms in immune competent host, but life threatening complication is seen in immune compromised patients and in pregnant women. Understanding the host-parasite interaction is critical for understanding the pathogenesis and biology parasite reactivation in the host. In this study, we used proteotrasncriptomics analyses by integrating the transcriptomics and proteomics data of T. gondii infected mouse liver to uncover the effector molecules responsible for disease pathogenesis that can be used as candidate markers for diagnosis and drug target. With this aim, we systematically integrated transcriptomicand proteomic data, representing the parasite infected mouse liver. Out of 2758 differentially expressed genes (DEGs) and 301 differentially expressed proteins (DEPs), 159 overlapping genes were identified. Among them, 86 genes were upregulated and 72 were downregulated in their respective mRNA and protein levels in the infected condition. Gene Ontology (GO) analysis revealed that the upregulated genes were mostly associated with immune system processes whereas the downregulated genes were involved in oxidation-reduction process and metabolism of lipid, and fatty acids. Protein-protein interaction (PPI) network analysis uncovered an interaction-hub including, Psmb8, Psmb9 and Tap1 for upregulated proteins and Cyp1A2, Cyp4A10 and Cyp3A11 for down-regulated proteins. Further studies are needed to validating these effector molecules. These molecules are likely to play a vital role in disease pathogenesis, as well as can be used as potential diagnostic marker and drug target candidates.

Identification of glycerophospholipid fatty acid remodeling by using mass spectrometry imaging in bisphenol S induced mouse liver

Bisphenol A（BPA） plays an important role in metabolic disorders. As a major alternative to BPA, it is unclear whether the exposure of bisphenol S（BPS） may result in lipidome disturbance. Using a mouse model, we investigated the effects of BPS exposure on metabolism and spatial distribution of lipids by using lipidomics analysis and matrix-assisted laser desorption/ionization（MALDI）-mass spectrometry imaging（MSI） in mouse liver tissues. Lipid metabolites displayed significant up-regulation in phosphatidylethanolamines（PE）, lysophosphatidylcholines（LPC）, lysophosphatidylethanolamines（LPE） and lysophosphatidylserine（LPS） as well as remarkable down-regulation in phosphatidylcholine（PC） and phosphatidylserine（PS） in mouse liver after the exposure at 100 m g BPS/kg body weight/day.The obtained results indicated that the lipidome of liver was perturbed significantly in glycerophospholipid（GP） fatty acid remodeling pathway upon the BPS exposure. We applied MSI and multivariate statistical analysis to evaluate the abundance variation of lipid markers in BPS-treated liver sections and to compare with the analytical results from olive oil-treated liver sections. Differential structural lipids with up-regulated PE（20：1/20：4）, LPC（20：4）, LPE（20：4）, LPS（33：4） and down-regulated PC（20：4/22：6）and PS（18：0/22：6）, which were related to GP fatty acid remodeling, changed and co-localized in the liver sections. To explore the cause of variation of lipid abundance, expression of enzymes that regulate biosynthesis and metabolism of fatty acid in liver tissues were analyzed. Consistent with the results of liver lipidome and spatial distribution, a decrease in hepatic expression of LPC acyltransferase 1（LPCAT1）,LPCAT2 and LPS acyltransferase and an increase expression of LPCAT3, LPCAT4, LPE acyltransferase 1（LPEAT1）, LPEAT2 and phospholipase A2 s were observed in GP fatty acid remodeling pathway. Our results demonstrated that exposure to BPS could induce the GP fatty acid remodeling, which might be useful in toxicity evaluation for bisphenols-induced hepatic diseases.

Human liver chimeric mouse model based on diphtheria toxin-induced liver injury

AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphtheria toxin receptor(DTR) transgenic mice and severe combined immune deficient(SCID)-beige mice,to create Alb-cre/DTR/SCID-beige(ADSB) mice,which coincidentally harbor Alb-cre and DTR transgenes and are immunodeficient. As the Cre expression is driven by the liver-specific promoter Alb(encoding ALB),the DTR stop signal flanked by two lox P sites can be deleted in the ADSB mice,resulting in DTR expression in the liver. ADSB mice aged 8-10 wk were injected intraperitoneally(i.p.) with diphtheria toxin(DT) and liver damage was assessed by serum alanine aminotransferase(ALT) level. Two days later,mouse livers were sampled for histological analysis,and human hepatocytes were transplanted into the livers on the same day. A human ALB enzyme-linked immunosorbent assay was performed 7,14,21 and 28 d after transplantation. Human CD68 immunohistochemistry was performed 30 and 90 d after transplantation.RESULTS We crossed Alb-cre with DTR and SCID-beige mice to obtain ADSB mice. These mice were found to have liver damage 4 d after i.p. injection of 2.5 ng/g bodyweight DT. Bodyweight began to decrease on day 2,increased on day 7,and was lowest on day 4(range,10.5%-13.4%). Serum ALT activity began to increase on day 2 and reached a peak value of 289.7 ± 16.2 IU/m L on day 4,then returned to background values on day 7. After transplantation of human liver cells,peripheral blood human ALB level was 1580 ± 454.8 ng/m L(range,750.2-3064.9 ng/m L) after 28 d and Kupffer cells were present in the liver at 30 d in ADSB mice.CONCLUSION Human hepatocytes were successfully repopulated in the livers of ADSB mice. The inducible mouse model of humanized liver in ADSB mice may have functional applications,such as hepatocyte transplantation,hepatic regeneration and drug metabolism.

Details determining the success in establishing a mouse orthotopic liver transplantation model

Liver transplantation(LT)is currently the only effective treatment option for endstage liver disease.The importance of animal models in transplantation is widely recognized among researchers.Because of the well-characterized mouse genome and the greater diversity and availability of both genetically modified animals and research reagents,mouse orthotopic LT(MOLT)has become an ideal model for the investigation of liver biology,tissue injury,regulation of alloimmunity and tolerance induction,and the pathogenesis of specific liver diseases.However,due to its complicated and technically demanding procedure,the model has merely been used by only a few research groups in the world for years.For a new learner,training lasting at least a couple of months or even years is required.Most of the investigators have emphasized the importance of elaborate techniques and dedicated instruments in establishing a MOLT model,but some details are often neglected.The nontechnical details are also significant,especially for researchers who have little experience in mouse microsurgery.Here,we review and summarize the crucial technical and nontechnical details in establishing the model of MOLT based on scientific articles and our experience in six aspects:animal selection,anesthesia,perioperative management,organ procurement,back-table preparation,and implantation surgery.We aim to enable research groups to shorten the learning curve and implement the mouse LT procedure with high technical success.

A novel animal model for in vivo study of liver cancer metastasis

AIM:To establish an animal model with human hepatocyte-repopulated liver for the study of liver cancer metastasis.METHODS:Cell transplantation into mouse livers was conducted using alpha-fetoprotein(AFP)-producing hu-man gastric cancer cells(h-GCCs) and h-hepatocytes as donor cells in a transgenic mouse line expressing urokinase-type plasminogen activator(uPA) driven by the albumin enhancer/promoter crossed with a severe combined immunodeficient(SCID) mouse line(uPA/SCID mice).Host mice were divided into two groups(A and B).Group A mice were transplanted with h-GCCs alone,and group B mice were transplanted with h-GCCs and h-hepatocytes together.The replacement index(RI),which is the ratio of transplanted h-GCCs and h-hepatocytes that occupy the examined area of a histological section,was estimated by measuring h-AFP and h-albumin concentrations in sera,respectively,as well as by immunohistochemical analyses of h-AFP and human cytokeratin 18 in histological sections.RESULTS:The h-GCCs successfully engrafted,repopulated,and colonized the livers of mice in group A(RI = 22.0% ± 2.6%).These mice had moderately differentiated adenocarcinomatous lesions with disrupted glandular structures,which is a characteristics feature of gastric cancers.The serum h-AFP level reached 211.0 ± 142.2 g/mL(range,7.1-324.2 g/mL).In group B mice,the h-GCCs and h-hepatocytes independently engrafted,repopulated the host liver,and developed colonies(RI = 12.0% ± 6.8% and 66.0% ± 12.3%,respectively).h-GCC colonies also showed typical adenocarcinomatous glandular structures around the h-hepatocyte-colonies.These mice survived for the full 56 day-study and did not exhibit any metastasis of h-GCCs in the extrahepatic regions during the observational period.The mice with an h-hepatocyte-repopulated liver possessed metastasized h-GCCs and therefore could be a useful humanized liver animal model for studying liver cancer metastasis in vivo.CONCLUSION:A novel animal model of human liver cancer metastasis was established using the uPA/SCID mouse line.This model could be useful for in vivo testing of anti-cancer drugs and for studying the mechanisms of human liver cancer metastasis.

Saeng-Kankunbi-Tang(生肝健脾汤) Protects Liver against Oxidative Damage through Activation of ERK/Nrf2 Pathway

Objective： To investigate the cytoprotective effects of Saeng-kankunbi-tang（生肝健脾汤, SKT）, a herbal prescription consisting of Artemisia capillaris and Alisma canaliculatum, and its underlying mechanism involved. Methods： In mice, blood biochemistry and histopathology were assessed in carbon tetrachloride（CCl4）-induced oxidative hepatic injury in vivo. The animal groups included vehicle-treated control, CCl4, SKT 500 mg/（kg·day） CCl4＋SKT 200 or 500 mg/（kg·day）. In Hep G2 cell, tert-butyl hydroperoxide（t BHP） induced severe oxidative stress and mitochondrial dysfunction in vitro. The cyto-protective effects of SKT were determined by 3-（4,5-dimethylthiazol）-2,5-diphenyltetrazolium bromide（MTT） assay, fluorescence activated cell sorting analysis and western blotting. Results： The administration of SKT prevented liver damage induced by CCl4 in mice, by inhibition of hepatocyte degeneration and inflammatory cell infiltration as well as plasma parameters such as alanine aminotransferase（P〈0.01）. Moreover, treatment with t BHP induced hepatocyte death and cellular reactive oxygen species production in hepatocyte cell line. However, SKT pretreatment（30–300 μg/m L） reduced this cell death and oxidative stress（P〈0.01）. More importantly, SKT inhibited the ability of t BHP to induce changes in mitochondrial membrane transition in cell stained with rhodamine 123（P〈0.01）. Furthermore, treatment with SKT induced extracellular signal-regulated kinases-mediated nuclear factor erythroid-2-related factor 2（Nrf2） activation as well as the expressions of heme oxygenase 1 and glutamate-cystein ligase catalytic, Nrf2 target genes. Conclusion： SKT has the ability to protect hepatocyte against oxidative stress and mitochondrial damage mediated by Nrf2 activation.

Insight into the deamination mechanism of 6-cyclopropylamino guanosine analogs for anti-HIV drug design

Deamination is a crucial step in the transformation of 6-cyclopropylamino guanosine prodrug to its active form. A convenient method using capillary electrophoresis （CE） without sample labeling was developed to analyze the deamination of a series of D-/L-6-cyclopropylamino guanosine analogs by mouse liver homogenate, mouse liver microsome, and adenosine deaminase （ADA）. A two-step process involving a 6-amino guanosine intermediate formed by oxidative N-dealkylation was demonstrated in the metabolism of 6-cyclopropylamino guanosine to 6-hydroxy guanosine. The results indicated that the transformation rates of different prodrugs to the active form varied greatly, which were closely correlated with the configuration of nucleosides and the structure of glycosyl groups. Most importantly, D-form analogs were metabolized much faster than their L-counterparts, thus clearly pointed out that compared to guanine, modification of glycosyl part might be a better choice for the development of L-Kuanosine analogs for the treatment of HIV,