Manual restraint and common compound administration routes in mice and rats

A rat-based preclinical platform facilitating transcatheter hepatic arterial infusion in immunodeficient rats with liver xenografts of patient-derived pancreatic ductal adenocarcinoma

Liver metastases from pancreatic ductal adenocarcinoma (PDAC) are highly fatal. A rat-based patient-derived tumor xenograft (PDX) model is available for transcatheter therapy. This study aimed to create an immunodeficient rat model with liver xenografts of patient-derived primary PDAC and evaluate efficacy of hepatic arterial infusion chemotherapy with cisplatin in this model. Three patient-derived PDACs were transplanted into the livers of 21 rats each (totally, 63 rats), randomly assigned into hepatic arterial infusion, systemic venous infusion, and control groups (n = 7 each) four weeks post-implantation. Computed tomography evaluated tumor volumes before and four weeks after treatment. Post-euthanasia, resected tumor specimens underwent histopathological examination. A liver-implanted PDAC PDX rat model was established in all 63 rats, with first CT identifying all tumors. Four weeks post-treatment, arterial infusion groups exhibited significantly smaller tumor volumes than controls for all three tumors on second CT. Xenograft tumors histologically maintained adenocarcinoma features compared to original patient tumors. Ki67 expression was significantly lower in arterial infusion groups than in the other two for the three tumors, indicating reduced tumor growth in PDX rats. A liver-implanted PDAC PDX rat model was established as a rat-based preclinical platform. Arterial cisplatin infusion chemotherapy represents a potential therapy for PDAC liver metastasis.

Evaluation of Potential Low-stress Handling Methods in Crl:CDSD Rats (Rattus norvegicus)

Low-stress handling methods have been studied in detail in mice, but relatively little research exists concerning preferred handling methods in rats. Most recommendations for low-stress handling of rats have been extrapolated from the mouse literature, despite known differences in handler interaction between the 2 species. The goal of the current study was to evaluate common methods of handling in rats, including application of recognized, low-stress handling methods from other species to rats, in order to determine relative stress levels associated with the handling methods. Seventy male and 70 female, 8-wk-old, Crl:CDSD rats, were housed either individually or in pairs, and were handled weekly or daily using one of the following methods: encircling of the torso (standard thoracic hold), handled using a tunnel, handled using a protective bite glove, handled using a soft paper towel, or tickled prior to being handled by the torso ( n = 10 per sex per treatment group). Body weight and clinical observations were scored at each handling session, abbreviated functional observation batteries were performed every other week, and an interaction test and hematology were conducted prior to study and on the day of study termination. Rats that were socially housed and handled weekly using the standard thoracic hold showed the least evidence of stress, while those that were singly housed and handled weekly using a protective bite glove or tunnel showed the highest level of stress. These effects were predominantly seen in males. This study suggests that standard low-stress handling methods used for other species may not be optimal for rats, and that additional research is needed to identify alternative methods to the standard thoracic hold that would further reduce stress during handling in rats.

A Combination Study of Pre- and Clinical Trial: Seaweed Consumption Reduces Aging-Associated Muscle Loss!

Seaweed consumption in Asian food cultures may benefit longevity and age-related conditions like sarcopenia with aging. However, sarcopenia lacks a definitive treatment, and pharmaceutical options have limitations in efficacy and safety. Recent studies on aging female mice found that Ishige okamurae (IO), a brown algae, and its active compound diphloroethohydroxycarmalol improved sarcopenia. Further research is needed to understand the effects of seaweed consumption on sarcopenia in humans. This clinical trial divided participants into a test group (receiving 500 mg/kg IO supplementation, mean±SD; age 62.73±7.18 years, n=40) and a control group (age 63.10±7.06 years, n=40). Hazard analysis assessed vital signs and muscle strength improvement during the trial. Additionally, 12-month-old mice were oral-fed IO at different doses (50, 100, 200 mg/kg) for 6-weeks. Aging and muscle-wasting related markers were evaluated, including grip strength, body weight and compositions, serum-parameters, and molecular-changes. The clinical trial found no significant changes in toxicity-parameters between the groups (p<0.05) after 12-weeks of IO supplementation. The IO group exhibited a remarkable increase in lower-limb quadriceps muscle-strength compared to the control (p=0.002). Furthermore, IO treatment improved age-related decline in quadriceps strength in the subgroup; under 61-years-old (p=0.004), without significant differences in foot-dominancy between groups (p=0.171). In 12-month-old male mice, IO administration improved age-related deficiencies in grip strength (p>0.0001) and testosterone (p=0.0001). Muscular regeneration parameters, such as lean-mass (p>0.0001), inhibition of proteolysis (measured by changes in myogenin and atrogin-1 protein expressions), cross-sectional myofiber area (p>0.0001), number of satellite cells (p=0.0001), and increased mitochondrial oxidative phosphorylation complexes in muscle tissue indicative of mitochondrial biogenesis, were also improved by IO administration. This trial is the first to explore the positive association between consuming brown-algae IO and age-related decreases in muscle strength. IO treatment helps maintain muscle mass and delays muscle wasting during aging, suggesting it as a potent nutritional strategy to protect against aging-associated sarcopenia.

Infective endocarditis: prevention strategy and risk factors in an animal model

INTRODUCTION

Infective endocarditis is a serious infection of the endocardium, especially the heart valves, which is associated with a high mortality rate. It generally occurs in patients with altered and abnormal cardiac architecture combined with exposure to bacteria from trauma and other potentially high-risk activities with transient bacteremia.

Double Staining with Fluorescent Tracers to Determine Myeloid Cell Migration of Leishmania-infected Cells from Mouse Skin to Lymphatic Tissues by Flow Cytometry

Immune cell trafficking in steady-state conditions and inflammatory cell recruitment into injured tissues is crucial for the surveillance of the immune system and the maintenance of body homeostasis. Tracking the cell journey from the infection site in the skin to lymphoid tissues has been challenging, and is typically determined using fluorescent cell tracers, antibodies, or photoconvertible models. Here, we describe the detailed method to track Leishmania-infected myeloid cells migrating from the skin to lymphatic tissues by multiparametric flow cytometry. These methods involve labeling of infective Leishmania donovani parasites with fluorescent cell tracers and phenotyping of myeloid cells with fluorescent antibodies, to determine the infection status of migratory myeloid cells. We also describe the detailed protocol to trace donor monocytes transferred intradermally into recipient mice in Leishmania donovani infection. These protocols can be adapted to study skin-lymphoid tissue migration of dendritic cells, inflammatory monocytes, neutrophils, and other phagocytic myeloid cells in response to vaccine antigens and infection. Key features • Cell-tracking of cell-trace-labeled parasites and monocytes from the skin to lymphatic tissues after transference into donor mice. • Identification of migratory cells labeled with fluorescent cell tracers and antibodies by flow cytometry. • Isolation, labeling, and transference of bone marrow monocytes from donor mice into the skin of recipient mice. • Description of a double-staining technique with fluorescent cell tracers to determine cell and parasite dissemination from the skin to lymphoid tissues.

Isolation, Purification, and Culture of Embryonic Melanoblasts from Green Fluorescent Protein-expressing Reporter Mice

In this article, we provide a method to isolate embryonic melanoblasts from reporter mouse strains. The mice from which these cells are isolated are bred into the ROSA26mT/mG reporter background, which results in green fluorescent protein (GFP) expression in the targeted melanoblast population. These cells are isolated and purified by fluorescence-activated cell sorting using GFP fluorescence. We also provide a method to culture the purified melanoblasts for further analysis. This method yields > 99% purity melanoblasts specifically targeted, and can be used for a variety of studies, including gene expression, clonogenic experiments, and biological assays, such as viability, capacity for directional migration, or differentiation into melanin-producing melanocytic cells.

In Vivo Pharmacokinetic and Pharmacodynamic Properties of the Antiarrhythmic Molecule ent-Verticilide

The unnatural verticilide enantiomer (ent-verticilide) is a selective and potent inhibitor of cardiac ryanodine receptor (RyR2) calcium release channels and exhibits antiarrhythmic activity in a murine model of catecholaminergic polymorphic ventricular tachycardia (CPVT). To determine verticilide's pharmacokinetic and pharmacodynamic properties in vivo, we developed a bioassay to measure nat- and ent-verticilide in murine plasma and correlated plasma concentrations with antiarrhythmic efficacy in a mouse model of CPVT. nat-Verticilide rapidly degraded in plasma in vitro, showing >95% degradation within 5 minutes, whereas ent-verticilide showed <1% degradation over 6 hours. Plasma was collected from mice following intraperitoneal administration of ent-verticilide at two doses (3 mg/kg, 30 mg/kg). Peak C max and area under the plasma-concentration time curve (AUC) scaled proportionally to dose, and the half-life was 6.9 hours for the 3-mg/kg dose and 6.4 hours for the 30-mg/kg dose. Antiarrhythmic efficacy was examined using a catecholamine challenge protocol at time points ranging from 5 to 1440 minutes after intraperitoneal dosing. ent-Verticilide inhibited ventricular arrhythmias as early as 7 minutes after administration in a concentration-dependent manner, with an estimated potency (IC50) of 266 ng/ml (312 nM) and an estimated maximum inhibitory effect of 93.5%. Unlike the US Food and Drug Administration-approved pan-RyR blocker dantrolene, the RyR2-selective blocker ent-verticilide (30 mg/kg) did not reduce skeletal muscle strength in vivo. We conclude that ent-verticilide has favorable pharmacokinetic properties and reduces ventricular arrhythmias with an estimated potency in the nanomolar range, warranting further drug development. SIGNIFICANCE STATEMENT: ent-Verticilide has therapeutic potential to treat cardiac arrhythmias, but little is known about its pharmacological profile in vivo. The primary purpose of this study is to determine the systemic exposure and pharmacokinetics of ent-verticilide in mice and estimate its efficacy and potency in vivo. The current work suggests ent-verticilide has favorable pharmacokinetic properties and reduces ventricular arrhythmias with an estimated potency in the nanomolar range, warranting further drug development.

American ginseng with different processing methods ameliorate immunosuppression induced by cyclophosphamide in mice via the MAPK signaling pathways

This study aimed to clarify the effects of two processed forms of American ginseng (Panax quinquefolius L.) on immunosuppression caused by cyclophosphamide (CTX) in mice. In the CTX-induced immunosuppressive model, mice were given either steamed American ginseng (American ginseng red, AGR) or raw American ginseng (American ginseng soft branch, AGS) by intragastric administration. Serum and spleen tissues were collected, and the pathological changes in mice spleens were observed by conventional HE staining. The expression levels of cytokines were detected by ELISA, and the apoptosis of splenic cells was determined by western blotting. The results showed that AGR and AGS could relieve CTX-induced immunosuppression through the enhanced immune organ index, improved cell-mediated immune response, increased serum levels of cytokines (TNF-α, IFN-γ, and IL-2) and immunoglobulins (IgG, IgA, and IgM), as well as macrophage activities including carbon clearance and phagocytic index. AGR and AGS downregulated the expression of BAX and elevated the expression of Bcl-2, p-P38, p-JNK, and p-ERK in the spleens of CTX-injected animals. Compared to AGS, AGR significantly improved the number of CD4⁺CD8^-T lymphocytes, the spleen index, and serum levels of IgA, IgG, TNF-α, and IFN-γ. The expression of the ERK/MAPK pathway was markedly increased. These findings support the hypothesis that AGR and AGS are effective immunomodulatory agents capable of preventing immune system hypofunction. Future research may investigate the exact mechanism to rule out any unforeseen effects of AGR and AGS.

Modulation of the Functional State of Mouse Neutrophils by Selenium Nanoparticles In Vivo

This study aimed to discover the immunomodulatory effect of selenium nanoparticles (SeNPs) on the functional state of neutrophils in vivo. Intraperitoneal injections of SeNPs (size 100 nm) 2.5 mg/kg/daily to BALB/c mice for a duration of 7-28 days led to the development of an inflammatory reaction, which was registered by a significant increase in the number of neutrophils released from the peritoneal cavity, as well as their activated state, without additional effects. At the same time, subcutaneous injections of the same SeNPs preparations at concentrations of 0.1, 0.5, and 2.5 mg/kg, on the contrary, modulated the functional state of neutrophils depending on the concentration and duration of SeNPs administration. With the use of fluorescence spectroscopy, chemiluminescence, biochemical methods, and PCR analysis, it was found that subcutaneous administration of SeNPs (0.1, 0.5, and 2.5 mg/kg) to mice for a short period of time (7-14 days) leads to modification of important neutrophil functions (adhesion, the number of migrating cells into the peritoneal cell cavity, ROS production, and NET formation). The obtained results indicated the immunostimulatory and antioxidant effects of SeNPs in vivo during short-term administration, while the most pronounced immunomodulatory effects of SeNPs were observed with the introduction of a low concentration of SeNPs (0.1 mg/kg). Increase in the administration time of SeNPs (0.1 mg/kg or 2.5 mg/kg) up to 28 days led to a decrease in the adhesive abilities of neutrophils and suppression of the expression of mRNA of adhesive molecules, as well as proteins involved in the generation of ROS, with the exception of NOX2; there was a tendency to suppress gene expression pro-inflammatory factors, which indicates the possible manifestation of immunosuppressive and anti-inflammatory effects of SeNPs during their long-term administration. Changes in the expression of selenoproteins also had features depending on the concentration and duration of the administered SeNPs. Selenoprotein P, selenoprotein M, selenoprotein S, selenoprotein K, and selenoprotein T were the most sensitive to the introduction of SeNPs into the mouse organism, which indicates their participation in maintaining the functional status of neutrophils, and possibly mediated the immunomodulatory effect of SeNPs.

Glucose-independent insulin and glucagon secreted from ventral pancreas sharing a similar pattern in healthy adult rat

Elevated blood glucose concentration due to food intake will trigger insulin secretion from the dorsal pancreas has been extensively studied. This increased intracellular insulin level can stimulate glucagon release from intra-islets. However, the interaction between glucagon and insulin under a fasting state is unknown. To explore the relationship, we partially removed the ventral and dorsal pancreas on wild-type adult rats. The glucose tolerance test was conducted to measure influence of the surgery on the integrity function of the pancreas. The fasting insulin/glucagon level before and after surgery were measured by the ELISA kit. The statistical analyses indicated that the ventral removal of the pancreas had higher fasting glucose than that of dorsal removal. And only the ventral removal group showed significantly increased basal insulin and basal glucagon levels. Our findings showed differential role of the ventral pancreas in response to a glucose-free stimulus and also provided the possible in vitro target for developing the anti-hyperglycemic drugs.

Models of Murine Vaginal Colonization by Anaerobically Grown Bacteria

The mammalian vagina can be colonized by many bacterial taxa. The human vaginal microbiome is often dominated by Lactobacillus species, but one-in-four women experience bacterial vaginosis, in which a low level of lactobacilli is accompanied by an overgrowth of diverse anaerobic bacteria. This condition has been associated with many health complications, including risks to reproductive and sexual health. While there is growing evidence showing the complex nature of microbial interactions in human vaginal health, the individual roles of these different anaerobic bacteria are not fully understood. This is complicated by the lack of adequate models to study anaerobically grown vaginal bacteria. Mouse models allow us to investigate the biology and virulence of these organisms in vivo. Other mouse models of vaginal bacterial inoculation have previously been described. Here, we describe methods for the inoculation of anaerobically grown bacteria and their viable recovery in conventionally raised C57Bl/6 mice. A new, less stressful procedural method for vaginal inoculation and washing is also described. Inoculation and viable recovery of Gardnerella are outlined in detail, and strategies for additional anaerobes such as Prevotella bivia and Fusobacterium nucleatum are discussed.

Nanoengineered Sprayable Therapy for Treating Myocardial Infarction

We report the development, as well as the in vitro and in vivo testing, of a sprayable nanotherapeutic that uses surface engineered custom-designed multiarmed peptide grafted nanogold for on-the-spot coating of an infarcted myocardial surface. When applied to mouse hearts, 1 week after infarction, the spray-on treatment resulted in an increase in cardiac function (2.4-fold), muscle contractility, and myocardial electrical conductivity. The applied nanogold remained at the treatment site 28 days postapplication with no off-target organ infiltration. Further, the infarct size in the mice that received treatment was found to be <10% of the total left ventricle area, while the number of blood vessels, prohealing macrophages, and cardiomyocytes increased to levels comparable to that of a healthy animal. Our cumulative data suggest that the therapeutic action of our spray-on nanotherapeutic is highly effective, and in practice, its application is simpler than other regenerative approaches for treating an infarcted heart.

Assessing In Vivo T Cell-Dependent Antigen-Specific Antibody Responses

Antibodies produced by plasma cells are a major arm of adaptive immunity. Germinal center reactions that include germinal center B cells and follicular T cells are fundamental players for antibody production, particularly antigen specific antibodies. Here we describe multiple methods that we and others have developed to analyze the production of antigen-specific antibodies in mice, with protocols for assessing antibody affinity and antibody isotype. The detection of antigen-specific IgE in serum using a traditional enzyme-linked immunosorbent assay (ELISA) method is often problematic due to much higher amounts of IgG. Thus we provide a specialized protocol for the detection of antigen-specific IgE in serum using ELISA.

Reporting Data on Auditory Brainstem Responses (ABR) in Rats: Recommendations Based on Review of Experimental Protocols and Literature

Research in hearing science is accelerating, and a wealth of data concerning auditory brainstem responses (ABR) in various animal models is published in peer-reviewed journals every year. Recently, we reviewed studies using ABR measurements in tinnitus rat models. We found significant discrepancies in the outcomes of these studies, some due to different research approaches and others due to different methodologies. Thus, the present work aimed to collect comprehensive information on all factors influencing ABR recordings in rats and compile recommendations on ABR data reporting. A questionnaire with queries about animal husbandry, transfer, handling, and the exact test conditions before, during, and after ABR recordings was sent to 125 researchers who published the relevant studies between 2015 and 2021. Eighteen researchers provided detailed answers on factors related to ABR measurements. Based on the analysis of the returned questionnaires, we identified three domains reflecting animal-, equipment-, and experiment-dependent factors that might influence the ABR outcome, thus requiring reporting in published research. The analysis of survey results led to the compilation of recommendations for reporting ABR outcomes supported by a literature review. Following these recommendations should facilitate comparative and meta-analyses of ABR results provided by various research groups.

Moxibustion improves ovarian function based on the regulation of the androgen balance

The effect of androgens on follicular development and female reproduction has become an active research topic. Moxibustion is a Traditional Chinese Medicine therapy that has been reported to be able to prevent and treat numerous ovary-related problems. However, studies on the effect of moxibustion for diminished ovarian reserve (DOR) on androgen balance are still lacking. The present study aimed to assess the efficacy of moxibustion intervention prior to disease onset and at the early stage of disease in a rat model of DOR and explore the mechanisms of its effect on ovarian function. A total of 32 rats were randomly divided into four groups: Blank group, Model group (a drug-induced model of DOR), Moxibustion group 1 and Moxibustion group 2. Moxibustion was performed on the BL23 and RN4 acupoints of female rats daily for a total of 20 days (once a day, five times a week for a total of 4 weeks). The two moxibustion groups were established with different intervention times: One group was subjected to pre-disease intervention and the other group to early-disease intervention. The ovarian function was evaluated by detecting anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), estradiol (E2), testosterone (T), dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT) and androgen receptor (AR) levels in the serum or the ovary samples. To further investigate the downstream regulatory factors for AR after moxibustion treatment for pre-disease or early-disease intervention, FSH receptor (FSHR) and microRNA (miR)-125b expression in ovaries were also analyzed. The results indicated that AMH and DHT levels were reduced in the model group compared with those in the blank group, while FSH, T and DHEA levels were increased. AMH and DHT levels were increased in Moxibustion group 1 compared with those in the model group, while FSH, T and DHEA levels were reduced. There was no difference in E2 levels between Moxibustion group 1 and the model group. Compared with that in the model group, the AR content in the ovary was increased in Moxibustion group 1. There was no difference in FSHR mRNA in the ovaries between Moxibustion group 1 and the model group. miR-125b levels were significantly increased in Moxibustion group 1 as compared with those in the model group. Furthermore, AMH and DHT levels were increased in Moxibustion group 2 compared with those in the model group, while FSH, T and DHEA levels were reduced. E2 levels were significantly decreased in Moxibustion group 2 compared with those in the model group. The relative mRNA expression of AR, FSHR and miR-125b was decreased following establishment of the model. Compared with that in the model group, the AR content in the ovary was increased in Moxibustion group 2. In comparison with the blank and model groups, the FSHR content in the ovary of Moxibustion group 2 was significantly increased. miR-125b levels were not obviously altered in Moxibustion group 2 as compared with those in the model group. In addition, there was no significant difference in AMH, FSH, T and DHEA levels between the two moxibustion groups. E2 and DHT levels were higher in Moxibustion group 1 than in Moxibustion group 2. There was no difference in AR mRNA expression between the two moxibustion groups. FSHR mRNA levels were lower in Moxibustion group 1 than in Moxibustion group 2, while miR-125b mRNA levels were higher in Moxibustion group 1 than in Moxibustion group 2. In conclusion, the present study suggested that moxibustion intervention prior to disease onset and at the early disease stage was able to improve ovarian function via modulation of the AR-mediated stable equilibrium of androgens. However, the effects and mechanisms of moxibustion intervention for pre-disease and early-disease intervention of DOR appear to be different. The appropriate duration of treatment and the time-effect relationship require to be further studied.

Enrichment of Neutrophils and Monocytes From the Liver Following Either Oral or Intravenous Listeria monocytogenes Infection

Listeria monocytogenes is a foodborne pathogen that causes serious, often deadly, systemic disease in susceptible individuals such as neonates and the elderly. These facultative intracellular bacteria have been an invaluable tool in immunology research for more than three decades. Intravenous (i.v.) injection is the most commonly used transmission route in mice, but oral models of infection have also been developed in recent years, and these may be more appropriate for many studies. This article includes detailed instructions for use of either foodborne or i.v. inoculation of mice and discusses the rationale for choosing either model. Additionally, a protocol is provided for enrichment of neutrophils and monocytes from the infected liver in a manner that allows for determination of bacterial burden while still providing sufficient cells for use in flow cytometric analysis or in vitro assays. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Foodborne L. monocytogenes infection Support Protocol 1: Preparing L. monocytogenes for foodborne infection Basic Protocol 2: Intravenous L. monocytogenes infection Support Protocol 2: Preparing L. monocytogenes for intravenous infection Basic Protocol 3: Enrichment of non-parenchymal cells from the infected liver.

Human amnion-derived mesenchymal stem cells improved the reproductive function of age-related diminished ovarian reserve in mice through Ampk/FoxO3a signaling pathway

Background

Age-related diminished ovarian reserve (AR-DOR) reduced the quality of oocytes, resulting in decreased female fertility. Aging is tightly related to abnormal distribution and function of mitochondria, while mitophagy is a major process to maintain normal quality and quantity of mitochondria in cells, especially in oocytes which containing a large number of mitochondria to meet the demand of energy production during oocyte maturation and subsequent embryonic development. Ampk/FoxO3a signaling is crucial in the regulation of mitophagy. It is reported mesenchymal stem cells (MSCs) can improve ovarian function. Here we aim to explore if human amnion-derived mesenchymal stem cells (hAMSCs) are effective in improving ovarian function in AR-DOR mice and whether Ampk/FoxO3a signaling is involved.

Methods

The AR-DOR model mice were established by 32-week-old mice with 3–8 litters, significantly low serum sex hormone levels and follicle counts. The old mice were divided into 5 treatment groups: normal saline (NS, control), 1% human serum albumin (HSA, resolver), low dose (LD, 5.0 × 10⁶cells/kg), middle dose (MD, 7.5 × 10⁶cells/kg), and high dose (HD, 10.0 × 10⁶cells/kg). The prepared hAMSCs were injected through tail vein. Serum sex hormone level, follicle counts, fertilization rate, gestation rate, little size, apoptosis of granulosa and stromal cells, expression level of Sod2, Ampk, and ratio of phosphorylated FoxO3a to total FoxO3a in ovaries were examined.

Results

Our results show that after hAMSC transplantation, the ovarian function in AR-DOR mice was significantly improved, meanwhile the apoptosis of granulosa and stromal cells in the ovaries was significantly repressed, the expression level of Ampk and the ratio of phosphorylated FoxO3a to total FoxO3a both were significantly increased, meanwhile increased Sod2 expression was also observed.

Conclusion

Our results demonstrate hAMSC transplantation via tail-injection can improve ovarian function of AR-DOR mice through Ampk/FoxO3a signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02382-x.

Single or Repeated Ablation of Mouse Olfactory Epithelium by Methimazole

Odor-detecting olfactory sensory neurons residing in the nasal olfactory epithelium (OE) are the only neurons in direct contact with the external environment. As a result, these neurons are subjected to chemical, physical, and infectious insults, which may be the underlying reason why neurogenesis occurs in the OE of adult mammals. This feature makes the OE a useful model for studying neurogenesis and neuronal differentiation, with the possibility for systemic as well as local administration of various compounds and infectious agents that may interfere with these cellular processes. Several different chemical compounds have been shown to cause toxic injury to the OE, which can be used for OE ablation. We, and others, have found that the systemic administration of the hyperthyroid drug, methimazole, reliably causes olfactotoxicity as a side effect. Here, we outline an OE lesioning protocol for single or repeated ablation by methimazole. A single methimazole administration can be used to study neuroepithelial regeneration and stem cell activation, while repeated ablation and regeneration of OE enable the study of tissue stem cell exhaustion and generation of tissue metaplasia.

Long-term oral administration of a novel estrogen receptor beta agonist enhances memory and alleviates drug-induced vasodilation in young ovariectomized mice

Development of estrogen therapies targeting the β (ERβ) but not α (ERα) estrogen receptor is critically needed for the treatment of negative menopausal symptoms, as ERα activation increases health risks like cancer. Here, we determined the effects of long-term oral treatment with EGX358, a novel highly selective ERβ agonist, on memory, vasodilation, and affect in young ovariectomized mice. Mice were orally gavaged daily for 9 weeks with vehicle, 17β-estradiol (E₂), the ERβ agonist diarylpropionitrile (DPN), or EGX358 at doses that enhance memory when delivered acutely. Tail skin temperature was recorded as a proxy for vasodilation following injection of vehicle or senktide, a tachykinin receptor 3 agonist used to model hot flashes. Anxiety-like behavior was assessed in the open field (OF) and elevated plus maze (EPM), and depression-like behavior was measured in the tail suspension (TST) and forced swim tests (FST). Finally, memory was assessed in object recognition (OR) and object placement (OP) tasks. E₂, DPN, and EGX358 reduced senktide-mediated increases in tail skin temperature compared to vehicle. All three treatments also enhanced memory in the OR and OP tasks, whereas vehicle did not. Although E₂ increased time spent in the center of the OF, no other treatment effects were observed in the OF, EPM, TST, or FST. These data suggest that long-term ERβ activation can reduce hot flash-like symptoms and enhance spatial and object recognition memories in ovariectomized mice. Thus, the highly selective ERβ agonist EGX358 may be a promising avenue for reducing menopause-related hot flashes and memory dysfunction.

Oral application of clozapine-N-oxide using the micropipette-guided drug administration (MDA) method in mouse DREADD systems

The designer receptor exclusively activated by designer drugs (DREADD) system is one of the most widely used chemogenetic techniques to modulate the activity of cell populations in the brains of behaving animals. DREADDs are activated by acute or chronic administration of their ligand, clozapine-N-oxide (CNO). There is, however, a current lack of a non-invasive CNO administration technique that can control for drug timing and dosing without inducing substantial distress for the animals. Here, we evaluated whether the recently developed micropipette-guided drug administration (MDA) method, which has been used as a non-invasive and minimally stressful alternative to oral gavages, may be applied to administer CNO orally to activate DREADDs in a dosing- and timing-controlled manner. Unlike standard intraperitoneal injections, administration of vehicle substances via MDA did not elevate plasma levels of the major stress hormone, corticosterone, and did not attenuate exploratory activity in the open field test. At the same time, however, administration of CNO via MDA or intraperitoneally was equally efficient in activating hM3D_Gq-expressing neurons in the medial prefrontal cortex, as evident by time-dependent increases in mRNA levels of neuronal immediate early genes (cFos, Arc and Zif268) and cFos-immunoreactive neurons. Compared to vehicle given via MDA, oral administration of CNO via MDA was also found to potently increase locomotor activity in mice that express hM3D_Gq in prefrontal neurons. Taken together, our study confirms the effectiveness of CNO given orally via MDA and provides a novel method for non-stressful, yet well controllable CNO treatments in mouse DREADD systems.

Differential Action of Connexin Hemichannel and Pannexin Channel Therapeutics for Potential Treatment of Retinal Diseases

Dysregulation of retinal function in the early stages of light-induced retinal degeneration involves pannexins and connexins. These two types of proteins may contribute to channels that release ATP, leading to activation of the inflammasome pathway, spread of inflammation and retinal dysfunction. However, the effect of pannexin channel block alone or block of both pannexin channels and connexin hemichannels in parallel on retinal activity in vivo is unknown. In this study, the pannexin channel blocker probenecid and the connexin hemichannel blocker tonabersat were used in the light-damaged rat retina. Retinal function was evaluated using electroretinography (ERG), retinal structure was analyzed using optical coherence tomography (OCT) imaging and the tissue response to light-induced injury was assessed immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1 (Iba-1) and Connexin43 (Cx43). Probenecid did not further enhance the therapeutic effect of connexin hemichannel block in this model, but on its own improved activity of certain inner retina neurons. The therapeutic benefit of blocking connexin hemichannels was further evaluated by comparing these data against results from our previously published studies that also used the light-damaged rat retina model. The analysis showed that treatment with tonabersat alone was better than probenecid alone at restoring retinal function in the light-damaged retina model. The results assist in the interpretation of the differential action of connexin hemichannel and pannexin channel therapeutics for potential treatment of retinal diseases.

Hippocampal insulin resistance and the Sirtuin 1 signaling pathway in diabetes-induced cognitive dysfunction

In the peripheral nervous system, the activation of Sirtuin 1 can improve insulin resistance; however, the role played by Sirtuin 1 in the central nervous system remains unknown. In this study, rat models of diabetes mellitus were generated by a single injection of streptozotocin. At 8 weeks after streptozotocin injection, the Morris water maze test and western blot assays confirmed that the diabetic model rats had learning and memory deficits, insulin resistance, and Sirtuin 1 expression could be detected in the hippocampus. Insulin and the insulin receptor inhibitor S961 were intranasally administered to investigate the regulatory effects of insulin signaling on Sirtuin 1. The results showed that insulin administration improved the impaired cognitive function of diabetic model rats and increased the expression levels of phosphorylated insulin receptor, phosphorylated insulin receptor substrate 1, and Sirtuin 1 in the hippocampus. Conversely, S961 administration resulted in more severe cognitive dysfunction and reduced the expression levels of phosphorylated insulin receptor, phosphorylated insulin receptor substrate 1, and Sirtuin 1. The Sirtuin 1 activator SRT2104 and the inhibitor Sirtinol were injected into the lateral ventricle, which revealed that the activation of Sirtuin 1 increased the expression levels of target of rapamycin complex 1, phosphorylated cAMP-response element-binding protein, and brain-derived neurotrophic factor. Hippocampal dendritic length and spine density also increased in response to Sirtuin 1 activation. In contrast, Sirtinol decreased the expression levels of target of rapamycin complex 1, phosphorylated cAMP-response element-binding protein, and brain-derived neurotrophic factor and damaged the dendritic structure. These findings suggest that the Sirtuin 1 signaling pathway plays an important role in the development of insulin resistance-related cognitive deficits in diabetic rats. This study was approved by the Animal Ethics Welfare Committee of the First Affiliated Hospital of Hunan University of Chinese Medicine (approval No. ZYFY201811207) in November 2018.

Lactic Acid Bacteria as Delivery Vehicle for Therapeutics Applications

Lactic acid bacteria comprise a large group of Gram-positive organisms capable of converting sugar into lactic acid. They have been studied due to their therapeutic potential on the mucosal surface. Among the species, Lactococcus lactis is considered the model bacterium and it has been explored as an important vehicle for providing therapeutic molecules and antigens in the mucosa. They can be genetically engineered to produce a variety of molecules as well as deliver heterologous DNA and protein. DNA vaccines consist of the administration of a bacterial plasmid under the control of a eukaryotic promoter encoding the antigen of interest. The resulting proteins are capable of stimulating the immune system, becoming a promising technique for immunization against a variety of tumors and infection diseases and having several advantages compared to conventional nucleic acid delivery methods (such as bioballistic delivery, electroporation, and intramuscular administration).

Regulation of the KATP-JNK gap junction signaling pathway by immunomodulator astragaloside IV attenuates neuropathic pain

BACKGROUND AND OBJECTIVES

Gap junctions play a pivotal role in contributing to the formation of astroglial networks and in chronic pain. However, the mechanisms underlying the dysfunction of astroglial gap junctions in chronic pain have not been fully elucidated.

METHODS

Chronic constriction injury (CCI) of the sciatic nerve was used to establish rat neuropathic pain model. C6 cells were used to perform experiments in vitro. Von Frey hairs and Hargreave's method were used to determine the withdrawal threshold of rats. Protein expression was detected by immunofluorescence and western blotting.

RESULTS

Astragaloside IV (AST IV) significantly attenuated neuropathic pain and suppressed the excitation of spinal astrocytes in rats with CCI. The antinociceptive effect of AST IV was reversed by the gap junction decoupler carbenoxolone (CBX). AST IV inhibited the high expression of phosphorylated connexin 43 (p-Cx43) and p-c-Jun N-terminal kinase (p-JNK) in spinal cord of rats with CCI. JNK inhibitor alleviated neuropathic pain, which was reversed by CBX. JNK inhibitor decreased the high expression of p-Cx43 in both rats with CCI and tumor necrosis factor-alpha (TNF-α)-treated C6 cells. Additionally, the analgesic effect of AST IV was reversed by the adenosine triphosphate-sensitive potassium (K_ATP) channel blocker, glibenclamide (Glib). Glib abolished the inhibitory effects of AST IV on p-JNK and p-Cx43 both in vivo and in vitro. K_ATP channel opener (KCO) mimicked the inhibitory effects of AST IV on p-JNK and p-Cx43 in TNF-α-treated C6 cells.

CONCLUSION

Our results indicate that the sciatic nerve CCI induces the dysfunction of gap junctions in the spinal cord by activating K_ATP/JNK signaling to contribute to neuropathic pain. AST IV attenuates neuropathic pain via regulating the K_ATP-JNK gap junction axis.

In vivo Blood-brain Barrier Permeability Assays Using Clostridium perfringens Epsilon Toxin

In order for the brain to function properly, a carefully orchestrated homeostasis must be maintained. To help regulate this delicate balance, the brain has developed a highly selective blood-brain barrier (BBB). Under normal conditions, the BBB excludes harmful blood-borne material from the brain parenchyma. However, numerous neuropathological conditions can disrupt this barrier, causing BBB permeability and subsequent CNS dysfunction. Understanding the mechanisms involved in BBB permeability are essential to elucidating the pathology of various neurological disorders as well as identifying methods for drug delivery to the CNS. Here, we describe several in vivo methods to measure BBB permeability in mice using an array of diverse sized tracers including exogenous 376 Da fluorescein salt, 66.5 kDa bovine serum albumin, and 70 kDa dextran as well as endogenous 160 kDa mouse IgG. When administered intravenously, these substances are excluded from a healthy brain by the BBB. However, BBB dysfunction can allow entry of these tracers into the brain and this accumulation can be measured using spectrophotometry, fluorescent microscopy, and immunohistochemistry. We also describe a method to induce BBB permeability using Clostridium perfringens epsilon toxin. Finally, we include a short discussion about the advantages and disadvantages of each method and their appropriate downstream applications.

The design and implementation of restraint devices for the injection of pathogenic microorganisms into Galleria mellonella

The injection of laboratory animals with pathogenic microorganisms poses a significant safety risk because of the potential for injury by accidental needlestick. This is especially true for researchers using invertebrate models of disease due to the required precision and accuracy of the injection. The restraint of the greater wax moth larvae (Galleria mellonella) is often achieved by grasping a larva firmly between finger and thumb. Needle resistant gloves or forceps can be used to reduce the risk of a needlestick but can result in animal injury, a loss of throughput, and inconsistencies in experimental data. Restraint devices are commonly used for the manipulation of small mammals, and in this manuscript, we describe the construction of two devices that can be used to entrap and restrain G. mellonella larvae prior to injection with pathogenic microbes. These devices reduce the manual handling of larvae and provide an engineering control to protect against accidental needlestick injury while maintaining a high rate of injection.

Institutional protocols for the oral administration (gavage) of chemicals and microscopic microbial communities to mice: Analytical consensus

IMPACT STATEMENT

Institutional protocols designed for the oral administration of live microbial communities, either complex or microscopic (microcosmic), to mice do not exist. However, this approach is increasingly employed by investigators focusing on the gut microbiome in experimental research. Herein, we propose two analytically Kappa-based consensus protocols to promote reproducibility and standardization in research practices and describe biologically relevant factors in achieving optimal microbial engraftment of communities in germ-free mice.

Advances in Molecular Tools and In Vivo Models for the Study of Human Fungal Pathogenesis

Pathogenic fungi represent an increasing infectious disease threat to humans, especially with an increasing challenge of antifungal drug resistance. Over the decades, numerous tools have been developed to expedite the study of pathogenicity, initiation of disease, drug resistance and host-pathogen interactions. In this review, we highlight advances that have been made in the use of molecular tools using CRISPR technologies, RNA interference and transposon targeted mutagenesis. We also discuss the use of animal models in modelling disease of human fungal pathogens, focusing on zebrafish, the silkworm, Galleria mellonella and the murine model.

Mapping Mammary Tumor Traits in the Rat

For nearly a century, the rat has served as a key model for studying the pathophysiology and genetic risk modifiers of breast cancer. Rat mammary tumors that initiate after exposure to carcinogens or estrogens closely resemble the etiological, histopathological, and genomic features of human breast cancer. Recent developments in genome-editing techniques in the rat have also enabled the development of sophisticated models for identifying the genetic modifiers of the nonmalignant tumor microenvironment that contribute to the formation, progression, and outcome of breast cancer. In this protocol review, we discuss the current methodologies for the three genetic mapping techniques in the rat that are widely used for identifying and testing the heritable genetic modifiers of breast cancer.

Gastrointestinal dysfunction in patients and mice expressing the autism-associated R451C mutation in neuroligin-3

Gastrointestinal (GI) problems constitute an important comorbidity in many patients with autism. Multiple mutations in the neuroligin family of synaptic adhesion molecules are implicated in autism, however whether they are expressed and impact GI function via changes in the enteric nervous system is unknown. We report the GI symptoms of two brothers with autism and an R451C mutation in Nlgn3 encoding the synaptic adhesion protein, neuroligin-3. We confirm the presence of an array of synaptic genes in the murine GI tract and investigate the impact of impaired synaptic protein expression in mice carrying the human neuroligin-3 R451C missense mutation (NL3^R451C ). Assessing in vivo gut dysfunction, we report faster small intestinal transit in NL3^R451C compared to wild-type mice. Using an ex vivo colonic motility assay, we show increased sensitivity to GABA_A receptor modulation in NL3^R451C mice, a well-established Central Nervous System (CNS) feature associated with this mutation. We further show increased numbers of small intestine myenteric neurons in NL3^R451C mice. Although we observed altered sensitivity to GABA_A receptor modulators in the colon, there was no change in colonic neuronal numbers including the number of GABA-immunoreactive myenteric neurons. We further identified altered fecal microbial communities in NL3^R451C mice. These results suggest that the R451C mutation affects small intestinal and colonic function and alter neuronal numbers in the small intestine as well as impact fecal microbes. Our findings identify a novel GI phenotype associated with the R451C mutation and highlight NL3^R451C mice as a useful preclinical model of GI dysfunction in autism. Autism Res 2019, 12: 1043-1056. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: People with autism commonly experience gastrointestinal problems, however the cause is unknown. We report gut symptoms in patients with the autism-associated R451C mutation encoding the neuroligin-3 protein. We show that many of the genes implicated in autism are expressed in mouse gut. The neuroligin-3 R451C mutation alters the enteric nervous system, causes gastrointestinal dysfunction, and disrupts gut microbe populations in mice. Gut dysfunction in autism could be due to mutations that affect neuronal communication.

Assessment of SIRT2 Inhibitors in Mouse Models of Cancer

New therapeutics directed against established and novel molecular targets are urgently needed to intervene against cancer. Recently, it was reported that several members of the sirtuin family (SIRT1-7), the mammalian orthologs of the silent information regulator 2 (Sir2) protein in Saccharomyces cerevisiae, play important roles in carcinogenesis. Although SIRT2 has been attributed both tumor-promoting and tumor-suppressing activities in different contexts, selective SIRT2 inhibition with a small molecule mechanism-based inhibitor known as Thiomyristoyl lysine (TM) repressed the growth of breast cancer cell lines. In light of the anticancer effect of SIRT2 inhibition in cell culture, it was critical to assess the efficacy of TM as a potential anticancer therapy in vivo. This was accomplished by testing the SIRT2 inhibitor in genetically engineered and xenotransplantation mouse models of breast cancer, using the procedures detailed in this chapter.

Lung microRNA Profiling Across the Estrous Cycle in Ozone-exposed Mice

MicroRNA (miRNA) profiling has become of interest to researchers working in various research areas of biology and medicine. Current studies show a promising future of using miRNAs in the diagnosis and care of lung diseases. Here, we define a protocol for miRNA profiling to measure the relative abundance of a group of miRNAs predicted to regulate inflammatory genes in the lung tissue from of an ozone-induced airway inflammation mouse model. Because it has been shown that circulating sex hormone levels can affect the regulation of lung innate immunity in females, the purpose of this method is to describe an inflammatory miRNA profiling protocol in female mice, taking into consideration the estrous cycle stage of each animal at the time of ozone exposure. We also address applicable bioinformatics approaches to miRNA discovery and target identification methods using limma, an R/Bioconductor software, and functional analysis software to understand the biological context and pathways associated with differential miRNA expression.

Intranasal Delivery of Adenoviral and AAV Vectors for Transduction of the Mammalian Peripheral Olfactory System

Intranasal delivery of solutions is a straightforward methodology for viral vector transduction and gene transfer to the epithelia within the nasal cavity. Beyond the simplicity of the technique, intranasal delivery has demonstrated restricted transduction of the olfactory and respiratory epithelial tissues. Here we outline the procedure of viral vector intranasal delivery in early postnatal and adult mice, as well as adult rats. The procedure allows for robust transduction and ectopic gene delivery that can be used for the visualization of cellular structures, protein distribution, and assessment of viral vector-mediated therapies.

Alterations of blood chemistry, hepatic and renal function, and blood cytometry in acrylamide-treated rats

Acrylamide is a vinyl monomer that is widely used for the synthesis of polyacrylamides, the treatment of drinking water, and as an additive in cosmetics. Acrylamide is also produced during the thermal processing of carbohydrate-rich foods. Although the potential toxic effects of acrylamide have been reported, few studies have evaluated biochemical parameters in blood. The present study investigated alterations of blood chemistry, hepatic function, and blood cytometry in acrylamide-treated rats. Thirty-two male Wistar rats were assigned to four experimental groups (n = 8/group): one control group received 0.3 ml of vehicle (saline solution), and the other three groups received acrylamide (25, 50, and 75 mg/kg, i.p., for 14 days). At the end of treatment, blood samples were collected to obtain serum, which was then processed using a Vitros250 device. For blood cytometry, the samples were processed in a Sysmex analyzer. The blood chemistry results showed that urea nitrogen, urea, and creatinine were elevated in the acrylamide-treated groups. Tests of hepatic function showed that total and direct bilirubins, transaminases, and alkaline phosphatase were also elevated compared with vehicle, whereas the levels of total proteins and albumin decreased. Blood cytometry showed that the levels of erythrocytes, hemoglobin, hematocrit, leukocytes, and platelets and mean cell volume decreased in the acrylamide-treated groups compared with vehicle. Overall, the present findings indicate that acrylamide causes deleterious effects on renal and hepatic physiology, producing dose-dependent alterations of blood chemistry and cytometry parameters in male Wistar rats.

Impact of repeated anesthesia with ketamine and xylazine on the well-being of C57BL/6JRj mice

Within the scope of the 3Rs of Russel and Burch, the number of laboratory animals can be reduced by repeated use of an animal. This strategy only becomes relevant, if the total amount of pain, distress or harm the individual animal experiences does not exceed the severity of a single manipulation. For example, when using imaging techniques, an animal can be examined several times during a study, but it has to be anesthetized each time imaging is performed. The severity of anesthesia is thought to be mild according to the Directive 2010/63/EU. However, the Directive does not differentiate between single and repeated anesthesia, although repeated anesthesia may have a greater impact on well-being. Hence, we compared the impact of single and repeated anesthesia (six times at an interval of three to four days) by injection of ketamine and xylazine (KX) on the well-being of adult female and male C57BL/6JRj mice. After anesthesia, well-being of mice was assessed according to a protocol for systematic assessment of well-being including nesting, the Mouse Grimace Scale (MGS), a test for trait anxiety, home cage activity, and the rotarod test for motor activity, food intake, and body weight, as well as corticosterone (metabolite) analysis. Repeated anesthesia increased the MGS in mice of both sexes and caused short-term effects on well-being of female mice in the immediate post-anesthetic period, indicated by longer lasting effects on trait anxiety-related behavior. However, corticosterone metabolite concentrations suggested that mice habituated to the stress induced by repeated KX administration. Hence, the mildly negative effects on well-being of repeated KX anesthesia do not seem to accumulate over time using the respective regimen. However, further observations for severity classification are warranted in order to more specifically determine the duration of mild distress and trait anxiety.

Immunostimulatory Agent Evaluation: Lymphoid Tissue Extraction and Injection Route-Dependent Dendritic Cell Activation

For evaluation of a new therapeutic agent for immunotherapy or vaccination, analysis of immune cell activation in lymphatic tissues is essential. Here, we investigated immunological effects of a novel lipid-DNA immunostimulant in nanoparticle form from different administration routes in the mouse: oral, intranasal, subcutaneous, footpad, intraperitoneal, and intravenous. These injections will directly influence the immune response, and harvesting lymphatic tissues and analysis of dendritic cell (DC) activation in the tissues are crucial parts of these evaluations. The extraction of mediastinal lymph nodes (mLNs) is important but quite complex because of the size and location of this organ. A stepwise procedure for harvesting the inguinal lymph node (iLN), mLN, and spleen and analyzing DC activation by flow cytometry is described.

A-C Estrogens as Potent and Selective Estrogen Receptor-Beta Agonists (SERBAs) to Enhance Memory Consolidation under Low-Estrogen Conditions

Estrogen receptor-beta (ERβ) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERβ agonists (SERBAs) with in vivo efficacy that are A-C estrogens, lacking the B and D estrogen rings. The most potent and selective A-C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the β over α isoform and with EC₅₀s of 20-30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the compound's ability to drive the productive conformational change needed to activate transcription. The compound also shows in vivo efficacy after microinfusion into the dorsal hippocampus and after intraperitoneal injection (0.5 mg/kg) or oral gavage (0.5 mg/kg). This simple yet novel A-C estrogen is selective, brain penetrant, and facilitates memory consolidation.

Acid-sensing ion channel 1 contributes to normal olfactory function

Acid-sensing ion channels (ASICs) are cation channels activated by protons. ASIC1a, a primary ASIC subunit in the brain, was recently characterized in the olfactory bulb. The present study tested the hypothesis that ASIC1a is essential for normal olfactory function. Olfactory behavior of wild-type (WT) and ASIC1-/- mice was evaluated by using three standard olfactory tests: (1) the buried food test, (2) the olfactory habituation test, and (3) the olfactory preference test. In buried food test, ASIC1-/- mice had significantly longer latency to uncover buried food than WT mice. In olfactory habituation test, ASIC1-/- mice had increased sniffing time with acidic odorants. In olfactory preference test, ASIC1-/- mice did not exhibit normal avoidance behavior for 2, 5- dihydro-2, 4, 5-trimethylthiazoline (TMT). Consistent with ASIC1 knockout, ASIC1 inhibition by nasal administration of PcTX1 increased the latency for WT mice to uncover the buried food. Together, these findings suggest a key role for ASIC1a in normal olfactory function.

Expression of Exogenous Cytokine in Patient-derived Xenografts via Injection with a Cytokine-transduced Stromal Cell Line

Patient-derived xenograft (PDX) mice are produced by transplanting human cells into immune deficient mice. These models are an important tool for studying the mechanisms of normal and malignant hematopoiesis and are the gold standard for identifying effective chemotherapies for many malignancies. PDX models are possible because many of the mouse cytokines also act on human cells. However, this is not the case for all cytokines, including many that are critical for studying normal and malignant hematopoiesis in human cells. Techniques that engineer mice to produce human cytokines (transgenic and knock-in models) require significant expense before the usefulness of the model has been demonstrated. Other techniques are labor intensive (injection of recombinant cytokine or lentivirus) and in some cases require high levels of technical expertise (hydrodynamic injection of DNA). This report describes a simple method for generating PDX mice that have exogenous human cytokine (TSLP, thymic stromal lymphopoietin) via weekly intraperitoneal injection of stroma that have been transduced to overexpress this cytokine. Use of this method provides an in vivo source of continuous cytokine production that achieves physiological levels of circulating human cytokine in the mouse. Plasma levels of human cytokine can be varied based on the number of stromal cells injected, and cytokine production can be initiated at any point in the experiment. This method also includes cytokine-negative control mice that are similarly produced, but through intraperitoneal injection of stroma transduced with a control vector. We have previously demonstrated that leukemia cells harvested from TSLP-expressing PDX, as compared to control PDX, exhibit a gene expression pattern more like the original patient sample. Together the cytokine-producing and cytokine-negative PDX mice produced by this method provide a model system that we have used successfully to study the role of TSLP in normal and malignant hematopoiesis.

Neurodevelopmental Reflex Testing in Neonatal Rat Pups

Neurodevelopmental reflex testing is commonly used in clinical practice to assess the maturation of the nervous system. Neurodevelopmental reflexes are also referred to as primitive reflexes. They are sensitive and consistent with later outcomes. Abnormal reflexes are described as an absence, persistence, reappearance, or latency of reflexes, which are predictive indices of infants that are at high risk for neurodevelopmental disorders. Animal models of neurodevelopmental disabilities, such as cerebral palsy, often display aberrant developmental reflexes, as would be observed in human infants. The techniques described assess a variety of neurodevelopmental reflexes in neonatal rats. Neurodevelopmental reflex testing offers the investigator a testing method that is not otherwise available in such young animals. The methodology presented here aims to assist investigators in examining developmental milestones in neonatal rats as a method of detecting early-onset brain injury and/or determining the effectiveness of therapeutic interventions. The methodology presented here aims to provide a general guideline for investigators.

Sustained epidermal powder drug delivery via skin microchannels

Transdermal delivery of hydrophilic drugs is challenging. This study presents a novel sustained epidermal powder delivery technology (sEPD) for safe, efficient, and sustained delivery of hydrophilic drugs across the skin. sEPD is based on coating powder drugs into high-aspect-ratio, micro-coating channels (MCCs) followed by topical application of powder drug-coated array patches onto ablative fractional laser-generated skin MCs to deliver drugs into the skin. We found sEPD could efficiently deliver chemical drugs without excipients and biologics drugs in the presence of sugar excipients into the skin with a duration of ~12h. Interestingly the sEPD significantly improved zidovudine bioavailability by ~100% as compared to oral gavage delivery. sEPD of insulin was found to maintain blood glucose levels in normal range for at least 6h in chemical-induced diabetes mice, while subcutaneous injection failed to maintain blood glucose levels in normal range. sEPD of anti-programmed death-1 antibody showed more potent anti-tumor efficacy than intraperitoneal injection in B16F10 melanoma models. Tiny skin MCs and 'bulk' drug powder inside relatively deep MCCs are crucial to induce the sustained drug release. The improved bioavailability and functionality warrants further development of the novel sEPD for clinical use.

The Dimethylnitrosamine Induced Liver Fibrosis Model in the Rat

Four to six week old, male Wistar rats were used to produce animal models of liver fibrosis. The process requires four weeks of administration of 10 mg/kg dimethylnitrosamine (DMN), given intraperitoneally for three consecutive days per week. Intraperitoneal injections were performed in the fume hood as DMN is a known hepatoxin and carcinogen. The model has several advantages. Firstly, liver changes can be studied sequentially or at particular stages of interest. Secondly, the stage of liver disease can be monitored by measurement of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes. Thirdly, the severity of liver damage at different stages can be confirmed by sacrifice of animals at designated time points, followed by histological examination of Masson's Trichome stained liver tissues. After four weeks of DMN dosing, the typical fibrosis score is 5 to 6 on the Ishak scale. The model can be reproduced consistently and has been widely used to assess the efficacy of potential anti-fibrotic agents.

Bisphenol A exposure and healing effects of Adiantum capillus-veneris L. plant extract (APE) in bisphenol A-induced reproductive toxicity in albino rats

The current study presents the bisphenol A exposure and the ameliorative effects of Adiantum capillus-veneris on testicular toxicity induced by bisphenol A. Adult male albino rats were divided into five groups of five animals each: A (control), B (vehicle control), C (toxic), D (protective), and E (ameliorative) were served distilled water, olive oil, bisphenol A (BPA) at 100 mg/kg body weight, A. capillus-veneris plant extract at 25 mg/kg body weight, and BPA + A. capillus-veneris, respectively. All of the doses were administered orally for 15 days, and the rats were then sacrificed. Blood samples for the testosterone assay and both testes were collected for histological examination. The body weight, paired testes weight, relative tissue weight index, Johnsen scoring of tubules, and level of serum testosterone decreased in BPA-treated rats. Similarly, histological examination of the testes in BPA-treated animals revealed a lower number of Leydig cells, an irregular basement membrane, sloughing of germinal layers, vacuolization, a lower number of spermatocytes, and debris in the lumen. However, co-administration of A. capillus-veneris with BPA increased the total antioxidative capacity (330.82 ± 22.46 μmol/mg protein) of the testes and restored the serum testosterone level (1.70 ng/ml); histological features showed restoration in the stages of spermatogenesis. Conclusively, A. capillus-veneris plant extract overcomes the estrogenic effects of BPA on the reproductive system of rats and protects rats' testes against BPA-induced injury/damage via an antioxidative mechanism that appears to be conciliated.

An Efficient and High Yield Method for Isolation of Mouse Dendritic Cell Subsets

Dendritic cells (DCs) are professional antigen-presenting cells primarily responsible for acquiring, processing and presenting antigens on antigen presenting molecules to initiate T-cell-mediated immunity. Dendritic cells can be separated into several phenotypically and functionally heterogeneous subsets. Three important subsets of splenic dendritic cells are plasmacytoid, CD8α(Pos) and CD8α(Neg) cells. The plasmacytoid DCs are natural producers of type I interferon and are important for anti-viral T cell immunity. The CD8α(Neg) DC subset is specialized for MHC class II antigen presentation and is centrally involved in priming CD4 T cells. The CD8α(Pos) DCs are primarily responsible for cross-presentation of exogenous antigens and CD8 T cell priming. The CD8α(Pos) DCs have been demonstrated to be most efficient at the presentation of glycolipid antigens by CD1d molecules to a specialized T cell population known as invariant natural killer T (iNKT) cells. Administration of Flt-3 ligand increases the frequency of migration of dendritic cell progenitors from bone marrow, ultimately resulting in expansion of dendritic cells in peripheral lymphoid organs in murine models. We have adapted this model to purify large numbers of functional dendritic cells for use in cell transfer experiments to compare in vivo proficiency of different DC subsets.

Utilizing an Orally Dissolving Strip for Pharmacological and Toxicological Studies: A Simple and Humane Alternative to Oral Gavage for Animals

Prior to testing novel therapeutics in humans, short and long term preclinical (i.e., animal), repetitive pharmacological and toxicological testing is required. In most cases, the preferred route of administration is via oral delivery. At the present time, oral delivery is mostly accomplished using an oral gavage procedure, in part, because it can achieve consistent and precise dosing in the animal model. Although this method is well established it does have complications that can result in a high rate of animal attrition. To this end, the procedure introduced here describes an alternative to the oral gavage method in which the desired drug is incorporated into a tastant, orally dissolving strip (ODS) that can simply be presented to the test animal where it is then rapidly taken up with minimal manipulation of the test subject. Herein, we demonstrate that preclinical, oral drug delivery using the ODS method represents a safe, convenient, and humane alternative to oral gavage.

The bm12 Inducible Model of Systemic Lupus Erythematosus (SLE) in C57BL/6 Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse clinical and immunological manifestations. Several spontaneous and inducible animal models mirror common components of human disease, including the bm12 transfer model. Upon transfer of bm12 splenocytes or purified CD4 T cells, C57BL/6 mice rapidly develop large frequencies of T follicular helper cells (Tfh), germinal center (GC) B cells, and plasma cells followed by high levels of circulating anti-nuclear antibodies. Since this model utilizes mice on a pure C57BL/6 background, researchers can quickly and easily study disease progression in transgenic or knockout mouse strains in a relatively short period of time. Here we describe protocols for the induction of the model and the quantitation Tfh, GC B cells, and plasma cells by multi-color flow cytometry. Importantly, these protocols can also be used to characterize disease in most mouse models of SLE and identify Tfh, GC B cells, and plasma cells in other disease models.

Intravenous Tomato Lectin Injection to Assess Functional Vasculature

Pluripotent stem cells have recently allowed for the development of tissue models for the various organ systems within the body. These models allow scientists to study organ function, physiology, embryology, and even pathologic processes. Studies on tissue can be done in vitro and/or transplanted into animal models for studies in vivo. Recently, our lab developed a model of human small intestine derived from human pluripotent stem cells which when transplanted in vivo, matured into an intestinal structure similar to that of adult intestine. The maturity of the transplanted human intestinal tissue was dependent upon the development of an adequate blood supply primarily from the murine host. In order to better study the developed vascular network within our transplanted intestinal tissue, we injected Fluorescein labeled Lycopersicon esculentum (tomato) lectin into the mouse tail vein (Watson et al., 2014). Using the property of this lectin to bind to the endothelium, we were able to visualize the vasculature within the transplant.

Diurnal, seasonal, and sex patterns of heart rate in grip-restrained African giant rats (Cricetomys gambianus, Waterhouse)

This study was carried out to determine heart rate (HR) values, including diurnal, seasonal, and sex patterns, in the African giant rat (Cricetomys gambianus, Waterhouse). HR was measured using stethoscope in grip-restrained African giant rats of either sex (103 bucks and 98 does), live-trapped from a tropical Savannah, and caged individually in the laboratory during the harmattan (cold-dry), hot-dry, and rainy seasons over a 3-year period. The HR fluctuated between 90 and 210 beats per minute (bpm) throughout the study period. Diurnal changes in HR (mean ± SEM) during the hot-dry and rainy seasons were nonsignificant (P > 0.05), but the morning and afternoon values differed (P < 0.01) during the cold-dry season. The HR varied (P < 0.05) among seasons, with peak, nadir, and moderate values recorded during the cold-dry (165.8 ± 0.51 bpm), hot-dry (153.1 ± 0.74 bpm), and rainy (163.4 ± 0.70 bpm) seasons, respectively. Mean HR of bucks was lower than that of does during the cold-dry (P < 0.0001) and hot-dry (P < 0.01) seasons, but sex difference during the rainy season was insignificant (P > 0.05). Overall, mean HR was lower (P < 0.0001) in bucks (158.8 ± 0.53 bpm) than in does (164.8 ± 0.53 bpm). In conclusion, values of HR in African giant rats are shown for the first time. Season, sex, and daytime influenced the HR, and should be considered during clinical evaluations of the rats.