Role of cancer stem cell ecosystem on breast cancer metastasis and related mouse models

Breast cancer metastasis is responsible for most breast cancer-related deaths and is influenced by many factors within the tumor ecosystem,including tumor cells and microenvironment.Breast cancer stem cells(BCSCs)constitute a small population of cancer cells with unique characteristics,including their capacity for self-renewal and differentiation.Studies have shown that BCSCs not only drive tumorigenesis but also play a crucial role in promoting metastasis in breast cancer.The tumor microenvironment(TME),composed of stromal cells,immune cells,blood vessel cells,fibroblasts,and microbes in proximity to cancer cells,is increasingly recognized for its crosstalk with BCSCs and role in BCSC survival,growth,and dissemination,thereby influencing metastatic ability.Hence,a thorough understanding of BCSCs and the TME is critical for unraveling the mechanisms underlying breast cancer metastasis.In this review,we summarize current knowledge on the roles of BCSCs and the TME in breast cancer metastasis,as well as the underlying regulatory mechanisms.Furthermore,we provide an overview of relevant mouse models used to study breast cancer metastasis,as well as treatment strategies and clinical trials addressing BCSC-TME interactions during metastasis.Overall,this study provides valuable insights for the development of effective therapeutic strategies to reduce breast cancer metastasis.

Comparison of immune responses and intestinal flora in epicutaneously sensitized BALB/c or C57BL/6 mouse models of food allergy

Cutaneous exposure to food allergens through a disrupted skin barrier is recognized as an important cause of food allergy,and the cutaneous sensitized mouse model has been established to investigate relevant allergic disorders.However,the role of different genetic backgrounds of mice on immune responses to food allergens upon epicutaneous sensitization is largely unknown.In this study,two strains of mice,i.e.,the BALB/c and C57BL/6 mice,were epicutaneously sensitized with ovalbumin on atopic dermatitis(AD)-like skin lesions,followed by intragastric challenge to induce IgE-mediated food allergy.Allergic outcomes were measured as clinical signs,specific antibodies and cytokines,and immune cell subpopulations,as well as changes in intestinal barrier function and gut microbiota.Results showed that both strains of mice exhibited typical food-allergic symptoms with a Th2-skewed response.The C57BL/6 mice,rather than the BALB/c mice,were fitter for establishing an epicutaneously sensitized model of food allergy since a stronger Th2-biased response and severer disruptions in the intestinal barrier and gut homeostasis were observed.This study provides knowledge for selecting an appropriate mouse model to study food-allergic responses associated with AD-like skin lesions and highlights the role of genetic variations in the immune mechanism underlying pathogenesis of food allergy.

Establishment and Evaluation of a Mouse Model of Allergic Rhinitis

[Objectives]To explore a new method for induction of allergic rhinitis in mice,and compare and evaluate it with common modeling methods.[Methods]36 mice were randomly divided into the control group,blank group and experimental group,and there were 12 mice in each group.The mice in the control group were conventionally induced.That is,the mice were first injected intraperitoneally with the mixture composed of OVA 50μg,[Al(OH)3]5 mg and 1ml of normal saline once every other day,and then since the 15 th d,20μL of 5%OVA solution was dropped into each nasal cavity once a day,which lasted for 7 d.The blank group was treated with the same amount of normal saline according to the control group,and received intraperitoneal injection and bilateral nasal drip respectively.In the experimental group,mice were first given intraperitoneal injection of the mixture composed of ovalbumin(OVA)75μg,aluminum hydroxide gel[Al(OH)3]8 mg and normal saline 1.5 mL for basic sensitization.On the 26 th d,20μL of 3%OVA solution was dropped into each nasal cavity once a day,which lasted for 10 d.The number of sneezes,the number of nose scratching,the amount of nasal discharge,and the activity of mice in each group were observed,and the behavior of allergic reaction was scored.Meanwhile,the number of eosinophils in the nasal discharge of mice and the IgE content in serum were measured.[Results]The score of nasal stimulation symptoms,the number of eosinophils and serum IgE level of mice in the control group and the experimental group were higher than those in the blank group(P<0.05),and there was no statistical significance between the two groups in the three indicators(P>0.05).[Conclusions]The modeling method was more suitable for the development of allergic rhinitis patients condition,and reduced the probability of death of mice due to modeling,and simplified the experimental operation.

Effects of Polygala fallax Hemsl Water Extract on a Mouse Model of Gastric Motility Disorders

[Objectives]To explore the effects of Polygona fallax Hemsl water extract on gastrointestinal motility in normal mice and gastric motility disorder model mice and approximate mechanism.[Methods]Using normal mice and mice with gastric motility disorders(modeled with atropine),the effects of different mass concentration groups of P.fallax Hemsl water extract(0.125,0.250,0.500 g/mL)and domperidone groups on gastric residual rate,small intestine propulsion rate,serum motilin(MLT),vasoactive intestinal peptide(VIP),and tissue morphology were studied.[Results]There was a highly significant difference(P<0.01)in the small intestine propulsion rate of liquid in normal mice among the different concentration groups of P.fallax Hemsl water extract compared to the blank group.The small intestine propulsion rate and gastric residue rate of semi-solid paste were statistically significant compared to the blank group(P<0.05).Among them,there was a highly significant difference between the high concentration group(67.75%±7.65%,46.5%±10.62%)and the medium concentration group(60.90%±5.87%,59.27%±7.82%)(P<0.01).There was statistical significance in normal mouse serum MLT content in the high concentration group(P<0.05).There was no effect on serum VIP levels in normal mice;no effect on the morphology of stomach and intestinal tissues of normal mice.The small intestine propulsion rate and gastric residue rate of liquid and semi-solid paste in mice with gastric motility disorders were statistically significant compared to the atropine group,with extremely significant differences(P<0.01).[Conclusions]P.fallax Hemsl water extract has a promoting effect on gastrointestinal motility.One of the specific mechanisms by which P.fallax Hemsl promotes gastrointestinal motility in normal mice may be related to the content of MLT in mouse serum.The mechanism of action in atropine induced gastric paresis mice may be related to the reactivation of M receptors,and the action mechanism of P.fallax Hemsl does not change the original histological basis.It can be inferred that P.fallax Hemsl water extract has a synergistic effect on promoting gastrointestinal motility through other mechanisms,but it is not fully understood and further in-depth research is needed.

MicroRNAs in mouse and rat models of experimental epilepsy and potential therapeutic targets

Epilepsy is a common and serious neurological disease that causes recurrent seizures. The brain damage caused by seizures can lead to depression, anxiety, cognitive impairment, or disability. In almost all cases chronic seizures are difficult to cure. MicroRNAs are widely expressed in the central nervous system and play important roles in the pathogenesis of several neurological disorders, including epilepsy. A variety of animals(mostly mice and rats) have been used to induce experimental epilepsy using different protocols and miRNA profiling performed. Most of the recent studies reviewed had performed miRNA profiling in hippocampal tissues and a large number of microRNAs were dysregulated when compared to controls. Most notably, miR-132-3p,-146a-5p,-10a-5p,-21a-3p,-27a-3p,-142a-5p,-212-3p,-431-5p, and-155 were upregulated in both the mouse and rat studies. Overexpression of miR-137 and miR-219 decreased seizure severity in a mouse epileptic model, and suppression of miR-451,-10a-5p,-21a-5p,-27a-5p,-142a-5p,-431-5p,-155, and-134 had a positive influence on seizure behavior. In the rat studies, overexpression of miR-139-5p decreased neuronal damage in drug-resistant rats and inhibition of miR-129-2-3p,-27a-3p,-155,-134,-181a, and-146a had a positive effect on seizure behavior and/or reduced the loss of neuronal cells. Further studies are warranted using adult female and immature male and female animals. It would also be helpful to test the ability of specific agomirs and antagomirs to control seizure activity in a subhuman primate model of epilepsy such as adult marmosets injected intraperitoneally with pilocarpine or cynomolgus monkeys given intrahippocampal injections of kainic acid.

Anti-infection effects of heparin on SARS-CoV-2 in a diabetic mouse model

Severe acute respiratory syndrome coronavirus 2(SARSCo V-2)infection can result in more severe syndromes and poorer outcomes in patients with diabetes and obesity.However,the precise mechanisms responsible for the combined impact of coronavirus disease 2019(COVID-19)and diabetes have not yet been elucidated,and effective treatment options for SARS-Co V-2-infected diabetic patients remain limited.To investigate the disease pathogenesis,K18-h ACE2 transgenic(h ACE2^(Tg))mice with a leptin receptor deficiency(h ACE2-Lepr^(-/-))and high-fat diet(h ACE2-HFD)background were generated.The two mouse models were intranasally infected with a 5×10^(5) median tissue culture infectious dose(TCID_(50))of SARSCo V-2,with serum and lung tissue samples collected at 3days post-infection.The h ACE2-Lepr^(-/-)mice were then administered a combination of low-molecular-weight heparin(LMWH)(1 mg/kg or 5 mg/kg)and insulin via subcutaneous injection prior to intranasal infection with1×10^(4) TCID_(50)of SARS-Co V-2.Daily drug administration continued until the euthanasia of the mice.Analyses of viral RNA loads,histopathological changes in lung tissue,and inflammation factors were conducted.Results demonstrated similar SARS-Co V-2 susceptibility in h ACE2^(Tg)mice under both lean(chow diet)and obese(HFD)conditions.However,compared to the h ACE2-Lepr^(+/+)mice,h ACE2-Lepr^(-/-)mice exhibited more severe lung injury,enhanced expression of inflammatory cytokines and hypoxia-inducible factor-1α(HIF-1α),and increased apoptosis.Moreover,combined LMWH and insulin treatment effectively reduced disease progression and severity,attenuated lung pathological changes,and mitigated inflammatory responses.In conclusion,preexisting diabetes can lead to more severe lung damage upon SARS-Co V-2 infection,and LMWH may be a valuable therapeutic approach for managing COVID-19patients with diabetes.

Research on the intelligent internet nursing model based on the child respiratory and asthma control test scale for asthma management of preschool children

BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills in children and the necessity for consistent involvement of a caregiver.With the rise of digital healthcare and the need for innovative interventions,Internet-based models can potentially offer relatively more efficient and patient-tailored care,especially in children.AIM To explore the impact of an intelligent Internet care model based on the child respiratory and asthma control test(TRACK)on asthma management in preschool children.METHODS The study group comprised preschoolers,aged 5 years or younger,that visited the hospital's pediatric outpatient and emergency departments between January 2021 and January 2022.Total of 200 children were evenly and randomly divided into the observation and control groups.The control group received standard treatment in accordance with the 2016 Guidelines for Pediatric Bronchial Asthma and the Global Initiative on Asthma.In addition to above treatment,the observation group was introduced to an intelligent internet nursing model,emphasizing the TRACK scale.Key measures monitored over a six-month period included the frequency of asthma attack,emergency visits,pulmonary function parameters(FEV1,FEV1/FVC,and PEF),monthly TRACK scores,and the SF-12 quality of life assessment.Post-intervention asthma control rates were assessed at six-month follow-up.RESULTS The observation group had fewer asthma attacks and emergency room visits than the control group(P<0.05).After six months of treatment,the children in both groups had higher FEV1,FEV1/FVC,and PEF(P<0.05).Statistically significant differences were observed between the two groups(P<0.05).For six months,children in the observation group had a higher monthly TRACK score than those in the control group(P<0.05).The PCS and MCSSF-12 quality of life scores were relatively higher than those before the nursing period(P<0.05).Furthermore,the groups showed statistically significant differences(P<0.05).The asthma control rate was higher in the observation group than in the control group(P<0.05).CONCLUSION TRACK based Intelligent Internet nursing model may reduce asthma attacks and emergency visits in asthmatic children,improve lung function,quality of life,and the TRACK score and asthma control rate.The effect of nursing was significant,allowing for development of an asthma management model.

Establishment and evaluation of a mouse model of bronchial asthma with Yin deficiency syndrome

Objective: To establish and evaluate a mouse model of bronchial asthma with Yin deficiency syndrome. Methods: The mouse model of bronchial asthma with Yin deficiency syndrome was established by the treatment with injecting ovalbumin(OVA) two times to sensitize, inhaling OVA 14 times to stimulate, and using thyroxin through lavage during late stimulation. This model was evaluated through body weight, asthmatic behaviors, respiratory function, autonomous activity, lung pathology, and pulmonary fluid clearance. Results: OVA combined with thyroxin was an appropriate method to induce the mouse model with increased food and water intake, autonomous activity, asthmatic behaviors score, and respiratory rate, decreased body weight, tidal volume, and wet/dry ratio of lung, and changed with pathology of lung tissue. The changes of the above mentioned parameters indicated that the model was the bronchial asthma with Yin deficiency syndrome. Conclusion: The OVA combined with thyroxin is a good pattern to establish a mouse model of bronchial asthma with Yin deficiency syndrome successfully, which can highly simulate the clinical symptoms of this disease.

Inhibition of Bcl-6 Expression Ameliorates Asthmatic Characteristics in Mice

Objective The function of Bcl-6 in T follicular helper(Tfh)cell maturation is indispensable,and Tfh cells play a pivotal role in asthma.This study investigated the impact of Bcl-6 on asthmatic traits.Methods The microscopic pathological alterations,airway resistance(AR),and lung compliance(LC)were determined in asthmatic mice and Bcl-6 interference mice.The surface molecular markers of Tfh cells and the Bcl-6 mRNA and protein expression were determined by flow cytometry,RT-qPCR,and Western blotting,respectively.The relationships between the Tfh cell ratio and the IgE and IgG1 concentrations in peripheral blood mononuclear cells(PBMCs)and bronchoalveolar lavage fluid(BALF)were determined.Results Asthmatic inflammatory changes were observed in the lung tissue and were attenuated by Bcl-6 siRNA and dexamethasone(DXM).Asthmatic mice exhibited an increased AR and a decreased LC,while Bcl-6 siRNA or DXM mitigated these changes.The percentages of Tfh cells and eosinophils were significantly increased in the asthmatic mice,and they significantly decreased after Bcl-6 inhibition or DXM treatment.RT-qPCR and Western blotting analyses revealed that the Bcl-6 expression level in PBMCs was significantly higher in asthmatic mice,and it decreased following Bcl-6 inhibition or DXM treatment.The IgE expression in the serum and BALF and the B cell expression in PBMCs exhibited a similar trend.In asthmatic mice,the ratio of Tfh cells in the peripheral blood showed a strong positive correlation with the IgE levels in the serum and BALF,but not with the IgG1 levels.Conclusion The amelioration of airway inflammation and airway hyper-responsiveness is achieved through Bcl-6 suppression,which effectively hinders Tfh cell differentiation,ultimately resulting in a concurrent reduction in IgE production.

Modeling human gastric cancers in immunocompetent mice

Gastric cancer(GC)is a major cause of cancer-related mortality worldwide.GC is determined by multiple(epi)genetic and environmental factors;can occur at distinct anatomic positions of the stomach;and displays high heterogeneity,with different cellular origins and diverse histological and molecular features.This heterogeneity has hindered efforts to fully understand the pathology of GC and develop efficient therapeutics.In the past decade,great progress has been made in the study of GC,particularly in molecular subtyping,investigation of the immune microenvironment,and defining the evolutionary path and dynamics.Preclinical mouse models,particularly immunocompetent models that mimic the cellular and molecular features of human GC,in combination with organoid culture and clinical studies,have provided powerful tools for elucidating the molecular and cellular mechanisms underlying GC pathology and immune evasion,and the development of novel therapeutic strategies.Herein,we first briefly introduce current progress and challenges in GC study and subsequently summarize immunocompetent GC mouse models,emphasizing the potential application of genetically engineered mouse models in antitumor immunity and immunotherapy studies.

A promising approach for quantifying focal stroke modeling and assessing stroke progression:optical resolution photoacoustic microscopy photothrombosis

To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly age-related.In this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed laser.We observed the molding process in mice of different ages and presented age-dependent vascular embolism differentiation.Moreover,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a stroke.Our imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.

Construction of Mouse Nutritional Obesity Model

[ Objective] The aim of this study is to construct the model for simple obesity induced by high-fat diet, which is closest to human obesity, laying a foundation for the studies of obesity related theories. [Method[ ICR and KM mice, half male and half female, were randomly divided into the high-fat diet experimental group and the normal diet control group based on body weights, and certain days later, body weight, Lee＇ s index, wet weight of adipose tissue, quantity of adipose cell in the same visual field and blood indices were measured. [Result]All indices mentioned a- bove of the female I CR mouse had significant statistical differences with those of the control group （P 〈 0.01 or P 〈 0.05）. [ Conclusion] To con- struct mouse nutritional obesity model successfully, different high-fat diets are required by different lines as well as different sexes in the same line.

Mouse models in male fertility research

Limited knowledge of the genetic causes of male infertility has resulted in few treatment and targeted therapeutic options. Although the ideal approach to identify infertility causing mutations is to conduct studies in the human population, this approach has progressed slowly due to the limitations described herein. Given the complexity of male fertility, the entire process cannot be modeled in vitro. As such, animal models, in particular mouse models, provide a valuable alternative for gene identification and experimentation. Since the introduction of molecular biology and recent advances in animal model production, there has been a substantial acceleration in the identification and characterization of genes associated with many diseases, including infertility. Three major types of mouse models are commonly used in biomedical research, including knockoutJknockin/gene-trapped, transgenic and chemical-induced point mutant mice. Using these mouse models, over 400 genes essential for male fertility have been revealed. It has, however, been estimated that thousands of genes are involved in the regulation of the complex process of male fertility, as many such genes remain to be characterized. The current review is by no means a comprehensive list of these mouse models, rather it contains examples of how mouse models have advanced our knowledge of post-natal germ cell development and male fertility regulation.

Human androgen deficiency： insights gained from androgen receptor knockout mouse models

The mechanism of androgen action is complex. Recently, significant advances have been made into our understanding of how androgens act via the androgen receptor （AR） through the use of genetically modified mouse models. A number of global and tissue-specific AR knockout （ARKO） models have been generated using the Cre-loxP system which allows tissue- and/or cell-specific deletion. These ARKO models have examined a number of sites of androgen action including the cardiovascular system, the immune and hemopoetic system, bone, muscle, adipose tissue, the prostate and the brain. This review focuses on the insights that have been gained into human androgen deficiency through the use of ARKO mouse models at each of these sites of action, and highlights the strengths and limitations of these Cre-loxP mouse models that should be considered to ensure accurate interpretation of the phenotype.

INT-767 improves histopathological features in a dietinduced ob/ob mouse model of biopsy-confirmed nonalcoholic steatohepatitis

AIM To characterize the efficacy of the dual FXR/TGR5 receptor agonist INT-767 upon histological endpoints in a rodent model of diet-induced and biopsy-confirmed non-alcoholic steatohepatitis(NASH).METHODS The effects of INT-767 on histological features of NASH were assessed in two studies using Lep^(ob/ob)(ob/ob) NASH mice fed the AMLN diet(high fat with transfat, cholesterol and fructose). In a proof-of-conceptstudy, Lep^(ob/ob)(ob/ob) NASH mice were first dosed with INT-767(3 or 10 mg/kg for 8 wk). A second ob/ob NASH study compared INT-767(3 and 10 mg/kg) to obeticholic acid(OCA)(10 or 30 mg/kg; 16 wk). Primary histological endpoints included qualitative and quantitative assessments of NASH. Other metabolic and plasma endpoints were also assessed. A comparative assessment of INT-767 and OCA effects on drug distribution and hepatic gene expression was performed in C57 Bl/6 mice on standard chow. C57 Bl/6 mice were orally dosed with INT-767 or OCA(1-30 mg/kg) for 2 wk, and expression levels of candidate genes were assessed by RNA sequencing and tissue drug levels were measured by liquid chromatography tandem-mass spectrometry.RESULTS INT-767 dose-dependently(3 and 10 mg/kg, PO, QD, 8 wk) improved qualitative morphometric scores on steatohepatitis severity, inflammatory infiltrates and fibrosis stage. Quantitative morphometric analyses revealed that INT-767 reduced parenchymal collagen area, collagen fiber density, inflammation(assessed by Galectin-3 immunohistochemistry) and hepatocyte lipid droplet area following INT-767 treatment. In a comparative study(16 wk), the FXR agonists OCA(10 and 30 mg/kg) and INT-767(3 and 10 mg/kg) both improved NASH histopathology, with INT-767 exerting greater therapeutic potency and efficacy than OCA. Mechanistic studies suggest that both drugs accumulate similarly within the liver and ileum, however, the effects of INT-767 may be driven by enhanced hepatic, but not ileal, FXR function. CONCLUSION These findings confirm the potential utility of FXR and dual FXR/TGR5 activation as disease intervention strategies in NASH.

Mesenchymal stem cell-derived exosomes promote neurogenesis and cognitive function recovery in a mouse model of Alzheimer’s disease

Studies have shown that mesenchymal stem cell-derived exosomes can enhance neural plasticity and improve cognitive impairment.The purpose of this study was to investigate the effects of mesenchymal stem cell-derived exosomes on neurogenesis and cognitive capacity in a mouse model of Alzheimer’s disease.Alzheimer’s disease mouse models were established by injection of beta amyloid 1?42 aggregates into dentate gyrus bilaterally.Morris water maze and novel object recognition tests were performed to evaluate mouse cognitive deficits at 14 and 28 days after administration.Afterwards,neurogenesis in the subventricular zone was determined by immunofluorescence using doublecortin and PSA-NCAM antibodies.Results showed that mesenchymal stem cells-derived exosomes stimulated neurogenesis in the subventricular zone and alleviated beta amyloid 1?42-induced cognitive impairment,and these effects are similar to those shown in the mesenchymal stem cells.These findings provide evidence to validate the possibility of developing cell-free therapeutic strategies for Alzheimer’s disease.All procedures and experiments were approved by Institutional Animal Care and Use Committee(CICUAL)(approval No.CICUAL 2016-011)on April 25,2016.

Mouse models of colorectal cancer: Past, present and future perspectives

Colorectal cancer(CRC)is the third most common diagnosed malignancy among both sexes in the United States as well as in the European Union.While the incidence and mortality rates in western,high developed countries are declining,reflecting the success of screening programs and improved treatment regimen,a rise of the overall global CRC burden can be observed due to lifestyle changes paralleling an increasing human development index.Despite a growing insight into the biology of CRC and many therapeutic improvements in the recent decades,preclinical in vivo models are still indispensable for the development of new treatment approaches.Since the development of carcinogen-induced rodent models for CRC more than 80 years ago,a plethora of animal models has been established to study colon cancer biology.Despite tenuous invasiveness and metastatic behavior,these models are useful for chemoprevention studies and to evaluate colitis-related carcinogenesis.Genetically engineered mouse models(GEMM)mirror the pathogenesis of sporadic as well as inherited CRC depending on the specific molecular pathways activated or inhibited.Although the vast majority of CRC GEMM lack invasiveness,metastasis and tumor heterogeneity,they still have proven useful for examination of the tumor microenvironment as well as systemic immune responses;thus,supporting development of new therapeutic avenues.Induction of metastatic disease by orthotopic injection of CRC cell lines is possible,but the so generated models lack genetic diversity and the number of suited cell lines is very limited.Patient-derived xenografts,in contrast,maintain the pathological and molecular characteristics of the individual patient's CRC after subcutaneous implantation into immunodeficient mice and are therefore most reliable for preclinical drug development–even in comparison to GEMM or cell line-based analyses.However,subcutaneous patient-derived xenograft models are less suitable for studying most aspects of the tumor microenvironment and anti-tumoral immune responses.The authors review the distinct mouse models of CRC with an emphasis on their clinical relevance and shed light on the latest developments in the field of preclinical CRC models.

Recent advances in mouse models of obesity-and nonalcoholic steatohepatitis-associated hepatocarcinogenesis

Hepatocellular carcinoma(HCC) is the fifth most common cancer, and obesity has been established as a risk factor for HCC development. Nonalcoholic steatohepatitis(NASH) is apparently the key link between obesity and hepatocarcinogenesis, and obesity also accelerates HCC development synergistically with other risk factors, such as hepatitis virus infection and alcohol consumption. As an explanation for the pathogenesis of NASH, the so-called "two-hit" theory has been widely accepted, but recently, a better model, the so-called "multiple-hits hypothesis" was proposed, which states that many disease-promoting factors may occur in parallel, rather than consecutively. However, the overall mechanism remains largely unknown. Various cell-cell and organ-organ interactions are involved in the pathogenesis of NASH, and thus appropriate in vivo disease models are essential for a deeper understanding. However, replicating the full spectrum of human NASH has been difficult, as NASH involves obesity, insulin resistance, steatohepatitis, fibrosis, and ultimately HCC, and the lack of an appropriate mouse model has been a considerable barrier to determining the missing links among obesity, NASH, and HCC. In recent years, several innovative mouse models presenting obesity- and NASHassociated HCC have been established by modified diets, chemotoxic agents, genetic manipulation, or a combination of these factors, shedding some light on this complex network and providing new therapeutic strategies. Thus, in this paper, I review the mouse models of obesity- and NASH-associated HCC, especially focusing on recent advances and their clinical relevance.

Hepatocellular carcinoma mouse models:Hepatitis B virusassociatedhepatocarcinogenesis and haploinsufficienttumor suppressor genes

The multifactorial and multistage pathogenesis of hepatocellular carcinoma(HCC)has fascinated a wide spectrum of scientists for decades.While a number of major risk factors have been identified,their mechanistic roles in hepatocarcinogenesis still need to be elucidated.Many tumor suppressor genes(TSGs)have been identified as being involved in HCC.These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors:the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele.Hepatitis B virus(HBV)is one of the most important risk factors associated with HCC.Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor,one advantage of mouse models for HBV/HCC research is the numerous and powerfulgenetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs.Here,we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner.Discoveries obtained using mouse models will have a great impact on HCC translational medicine.

Development of a mouse model of arecoline-induced oral mucosal fibrosis

Objective: To develop a BALB/c mouse model of oral submucous fibrosis(OSF)induced by arecoline and to exhibit an accumulation of collagen and angiogenesis changes.Methods: BALB/c mice were randomly assigned to either the control(distilled water) or experimental group(arecoline)(n = 40). Eight mice from each group were sacrificed every 4 weeks since 8 weeks post treatment. Changes in histopathologic features, levels of collagen type Ⅰ and collagen type Ⅲ, and angiogenesis were measured.Results: In the 8th week, epithelium atrophy, collagen cumulation and micrangium pathologic changes in the lamina propria were observed in the oral mucosa. In the 20th week, hyaline degeneration of the connective tissues was observed on the tongue and palate mucosa. The angiogenesis and collagen type Ⅰ changed significantly as the diseases advanced(P < 0.05); however, collagen type Ⅲ was not statistically different.Conclusions: An OSF model involving mice can be rapidly induced by drinking a highdose of arecoline. OSF angiogenic changes in mice primarily decrease and collagen accumulation is mainly collagen type Ⅰ.