Animal Models Research Articles

Maternal exposure to buprenorphine, but not methadone, during pregnancy reduces social play behavior across two generations of offspring.

The prevalence of newborns exposed to medications for opioid use disorder (MOUD), such as methadone or buprenorphine, during pregnancy is increasing. The opioid system plays a crucial role in regulating and shaping social behavior, and children prenatally exposed to opioids face an increased risk of developing behavioral problems. However, the impact of prenatal exposure to MOUD on offspring's social behavior during adolescence and adulthood, as well as potential intergenerational effects, remains largely unexplored. Our study employed a translationally relevant animal model to investigate how maternal (F0) exposure to MOUD during pregnancy affects social behavior in young and adult rats across the first (F1) and second (F2) generation of offspring. Female Sprague-Dawley rats were implanted with an osmotic minipump delivering methadone (10mg/kg/day), buprenorphine (1mg/kg/day), or sterile water, prior to mating with drug-naïve males. Adult F1 females were mated with treatment-matched F1 males to generate F2 offspring. We assessed social play behavior in juvenile offspring, and social interaction behavior in a three-chamber social interaction test in young adults of the F1 and F2 generations. Maternal exposure to buprenorphine, but not methadone, during pregnancy reduced social play behavior in both F1 and F2 offspring, expressed by a reduced number of pounces and pins, which are the two most characteristic parameters of social play in rats. Adult social interactions were unaffected by prenatal MOUD exposure across both generations. Maternal exposure to buprenorphine during pregnancy may have adverse effects on social play behavior across two generations of offspring.

ULK1 methylation promotes TGF-β1-induced endometrial fibrosis via the FOXP1/DNMT1 axis.

Intrauterine adhesion (IUA) is the second most common cause of secondary infertility in women and can also lead to menstrual abnormalities and multiple adverse pregnancy outcomes. Therefore, elucidating the mechanism of its development is crucial for the prevention and treatment of IUA. This study will investigate the function and mechanism of forkhead box P1 (FOXP1)/DNA methyltransferase 1 (DNMT1)/unc-51-like autophagy activating kinase 1 (ULK1) in IUA. Expression levels of key genes were detected using western blot and quantitative - real time reverse transcription polymerase chain reaction. Cell proliferation was detected by CCK-8 and EdU staining. Transcriptional regulation relationships were detected by dual luciferase reporter gene and chromatin immunoprecipitation (ChIP) assay. Methylation station of ULK1 was detected by methylmion specific PCR (MSP). Fibrosis and pathological changes in the uterine cavity tissues were detected by Masson and hematoxylin and eosin staining. It was observed that the expression of FOXP1 and DNMT1 increased in transforming growth factor (TGF)-β1-induced cells, while ULK1 expression decreased. Downregulation of FOXP1 could inhibit human endometrial stromal cells proliferation and autophagy, as well as decrease the expression of fibrogenic factors (collagen type I alpha 1 chain [COL1A1], fibronectin [FN], and alpha-smooth muscle actin [α-SMA]). The results of MSP and ChIP experiments showed that DNMT1 promotes methylation of the ULK1 promoter region and inhibits its transcription. In an animal model, knockdown of FOXP1 alleviated pathological fibrosis and uterine adhesions. Knockdown of FOXP1 can inhibit endometrial fibrosis in IUA rats; FOXP1 could be a potential target for the treatment of IUA.

Exploring Acoustic Detection of α-Synuclein Fibrils.

Over the past decades, the incidence of Parkinson's disease (PD) cases has doubled in industrialized countries. While patients over 70years old still represent more than half of the cases, the disease is increasingly affecting younger individuals. Environmental factors have been implicated, such as the effects of certain pesticides or chemicals on neurons, such as rotenone or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Researchers have also demonstrated the influence of genetic mutations in younger patients. A-synuclein is a protein encoded by the SNCA gene, known to undergo various mutations in hereditary cases of PD. These mutations alter the composition and spatial arrangements of α-synuclein. The proteins, originally of linear shape, aggregate during the progression of PD, forming fibrillary structures that propagate through brain tissues. Among the physical therapies investigated for treating α-synuclein aggregation, ultrasonic waves, capable of altering protein and cell behaviors, have recently been used to disrupt α-synuclein fibrils within tissues in cellular and animal models, with the hope of developing treatments based on ultrasound properties. However, detecting fibrils typically requires invasive and non-biocompatible chemical compounds or cumbersome machinery. In this study, our acoustic experimental setup allowed us to investigate the response of α-synuclein to ultrasound perturbations. By capturing the transmitted wave across proteins over a frequency range 10kHz to 10MHz, no ultrasound signature indicating the presence of proteins was observed.Significance Statement: The results report there is no ultrasound signature of the presence of α-synuclein fibrils, from 10kHz to 10MHz.

GLP-1 Receptor Agonists Alleviate Diabetic Kidney Injury via β-Klotho-Mediated Ferroptosis Inhibition.

Semaglutide (Smg), a GLP-1 receptor agonist (GLP-1RA), shows renal protective effects in patients with diabetic kidney disease (DKD). However, the exact underlying mechanism remains elusive. This study employs transcriptome sequencing and identifies β-Klotho (KLB) as the critical target responsible for the role of Smg in kidney protection. Smg treatment alleviates diabetic kidney injury by inhibiting ferroptosis in patients, animal models, and HK-2 cells. Notably, Smg treatment significantly increases the mRNA expression of KLB through the activation of the cyclic adenosine monophosphate (cAMP) signaling pathway, specifically through the phosphorylation of protein kinase A (PKA) and cAMP-response element-binding protein (CREB). Subsequently, the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway is activated, reprograming the key metabolic processes of ferroptosis such as iron metabolism, fatty acid synthesis, and the antioxidant response against lipid peroxidation. Suppression of ferroptosis by Smg further attenuates renal inflammation and fibrosis. This work highlights the potential of GLP-1RAs and KLB targeting as promising therapeutic approaches for DKD management.

Design, Synthesis and Biological Evaluation of Naphthalimide-Polyamine Conjugate as a Potential Anti-Colorectal Cancer Agent.

Colorectal cancer is the second most common cause of cancer-related death worldwide with a rising incidence, highlighting an urgent need for novel therapeutics. In this study, we developed several polyamine conjugates. Compound 6 (C6) was selected as the lead compound and was evaluated for anticancer activity in vitro and in vivo. In vitro experiments showed that C6 inhibited cell proliferation, colony formation, migration, and invasion of colorectal cancer cells while inducing apoptosis, pyroptosis, and autophagosomes formation. Genetic or pharmacological inhibition of autophagy weakened C6-induced apoptosis and gasdermin E (GSDME)-dependent pyroptosis. Inactivation of caspase 3 activity by AC-DEVD-CHO decreased the levels of N-terminal GSDME induced by C6. Furthermore, animal models exhibited suppressed tumor growth and dissemination after treatment with C6. Taken together, our findings highlight C6 as a potential drug against colorectal cancer.

Radiation protection and personal dosimetry in a core facility for multimodal small animal imaging.

Clinical imaging techniques such as positron emission tomography (PET) in combination with computed tomography (CT) are increasingly being used in biomedical research involving small animal models. The handling of open radioactive substances (radiopharmaceuticals) necessary for PET imaging requires prior official authorization for handling, the application of radiation protection principles, and regular training. The overriding aim of radiation protection is to protect the personnel directly involved, other persons, and the environment from the harmful effects of ionizing radiation.This paper aims to provide an overview of the regulatory requirements of the Radiation Protection Act (StrlSchG), the Radiation Protection Ordinance (StrlSchV), and the associated standards and guidelines. Furthermore, their implementation in practical work in small animal imaging using PET/CT is shown. We will focus on the individual steps of the imaging process, from delivery of the radiopharmaceuticals to waste disposal. This should provide interested researchers with an initial overview of the safe and successful use of the method. In addition, exposure values from the last six years in the literature were analyzed. While personal dosimetric monitoring in clinical PET/CT imaging has been extensively published, there is no published data known to us for personnel for PET/CT research with small animals. The evaluation of the personal dosimetric monitoring of our small animal imaging facility with 7 employees over 4 years revealed an increased personal and finger dose normalized to the injected activity and compared to human PET/CT imaging. Nevertheless, the annual personal dose or annual finger dose in small animal imaging (Hp(10): 1.7 mSv, Hp(0.07): 64 mSv) is lower than for personnel performing human PET/CT imaging at the local University Department of Nuclear Medicine (Hp(10): 3.8 mSv, Hp(0.07): 156 mSv) or published values, and is well below the legally permissible maximum dose of 20 or 500 mSv per year.The increasing use of PET/CT in small animal research can be safely utilized if the radiation protection principles are implemented and continuously trained. · PET/CT imaging in small animals is increasingly used in biomedical research.. · Radiation protection laws and guidelines have to be known and are relevant in animal experiments.. · Compared to published values from human medicine, activity-specific employee doses are increased in the presented imaging facility.. · The legal personal dose in the studied imaging facility is below legal limits.. · Schildt A, Sänger P, Lütgens M et al. Radiation protection and personal dosimetry in a core facility for multimodal small animal imaging. Fortschr Röntgenstr 2024; DOI 10.1055/a-2462-2419.

Dietary fructose enhances tumour growth indirectly via interorgan lipid transfer.

Fructose consumption has increased considerably over the past five decades, largely due to the widespread use of high-fructose corn syrup as a sweetener1. It has been proposed that fructose promotes the growth of some tumoursdirectly by serving as a fuel2,3. Here we show that fructose supplementation enhances tumour growth in animal models of melanoma, breast cancer and cervical cancer without causing weight gain or insulin resistance. The cancer cells themselves were unable to use fructose readily as a nutrient because they did not express ketohexokinase-C (KHK-C). Primary hepatocytes did express KHK-C, resulting in fructolysis and the excretion of a variety of lipid species, including lysophosphatidylcholines (LPCs). In co-culture experiments, hepatocyte-derived LPCs were consumed by cancer cells and used to generate phosphatidylcholines, the major phospholipid of cell membranes. In vivo, supplementation with high-fructose corn syrup increased several LPC species by more than sevenfold in the serum. Administration of LPCs to mice was sufficient to increase tumour growth. Pharmacological inhibition of ketohexokinase had no direct effect on cancer cells, but it decreased circulating LPC levels and prevented fructose-mediated tumour growth in vivo. These findings reveal that fructose supplementation increases circulating nutrients such as LPCs, which can enhance tumour growth through a cell non-autonomous mechanism.

Eco-friendly Synthesis and Molecular Modelling of 2-Phenylimidazo[1,2-b]pyridazine Derivatives: In Vitro and In Vivo Studies for Lead Optimization.

7-methyl-2-phenylimidazo[1,2-b]pyridazin-3-carboxylic acid (DM1) and 6-methoxy-2-phenylimidazo[1,2-b]pyridazin-3-carboxylic acid (DM2) have been shown to act as human (h) Cav3.1 voltage-gated calcium channel blockers with promising in vivo anti-absence activity, positioning them as potential antiepileptic drugs. The primary aim of this work was to develop cost-effective and environmentally friendly synthetic procedures for preparing 2-phenylimidazo[1,2-b]pyridazine derivatives. After optimizing the synthesis of this compound class using efficient and green techniques such as microwaves and ultrasound irradiation, we further evaluated the antiepileptic effects of DM1 and DM2 in two animal models: CD-1 ICR mice after pentylenetetrazol administration and DBA/2 mice with seizures induced by audiogenic stimuli. Their neuroprotective effect against oxidative stress were assessed using C6 rat brain glioma cells. DM1 and DM2 exhibited potent anti-seizure effects in both animal models and demonstrated significant in vitro neuroprotective activity by reducing reactive oxygen species release. To lay the groundwork for the future rational optimization of this promising class of compounds, the molecular bases of DM1 and DM2 activity were investigated by modelling their interaction with hCav3.1 channels. The calculated binding modes of DM1 and DM2 to hCav3.1 channels partially mirrored that of the selective Cav3.1 blocker Z944, paving the way for future lead optimization.

Expression of Neurotrophins and Its Receptors During Fetal Development in the Human Cochlea

We determined the relative expression levels of the receptors TrkA, TrkB, TrkC, and p75NTR and ligands BDNF, NT-3, NGF, and NT-4 with RNAseq analysis on fetal human inner ear samples, located TrkB and TrkC proteins, and quantified BDNF with in situ hybridization on histological sections between gestational weeks (GW) 9 to 19. Spiral ganglion neurons (SGNs) and satellite glia appear to be the main source of BDNF and synthesis peaks twice at GW10 and GW15–GW17. Tonotopical gradients of BDNF revert between GW8 and GW15 and follow a maturation and innervation density gradient in SGNs. NT-3/TrkC follows the same time course of expression as BDNF/TrkB. Immunostaining reveals that TrkB signaling may act mainly through satellite glia, Schwann cells, and supporting cells of Kölliker’s organ, while TrkC signaling targets SGNs and pillar cells in humans. The NT-4 expression is upregulated when BDNF/NT-3 is downregulated, suggesting a balancing effect for sustained TrkB activation during fetal development. The mission of neurotrophins expects nerve fiber guidance, innervation, maturation, and trophic effects. The data shall serve to provide a better understanding of neurotrophic regulation and action in human development and to assess the transferability of neurotrophic regenerative therapy from animal models.

Improving dexamethasone drug loading and efficacy in treating rheumatoid arthritis via liposome: Focusing on inflammation and molecular mechanisms.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects approximately 0.46% of the global population. Conventional therapeutics for RA, including disease-modifying antirheumatic drugs (DMARDs), nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids, frequently result in unintended adverse effects. Dexamethasone (DEX) is a potent glucocorticoid used to treat RA due to its anti-inflammatory and immunosuppressive properties. Liposomal delivery of DEX, particularly when liposomes are surface-modified with targeting ligands like peptides or sialic acid, can improve drug efficacy by enhancing its distribution to inflamed joints and minimizing toxicity. This study investigates the potential of liposomal drug delivery systems to enhance the efficacy and targeting of DEX in the treatment of RA. Results from various studies demonstrate that liposomal DEX significantly inhibits arthritis progression in animal models, reduces joint inflammation and damage, and alleviates cartilage destruction compared to free DEX. The liposomal formulation also shows better hemocompatibility, fewer adverse effects on body weight and immune organ index, and a longer circulation time with higher bioavailability. The anti-inflammatory mechanism is associated with the downregulation of pro-inflammatory cytokines like tumor necrosis factor-α (TNF-α) and B-cell-activating factor (BAFF), which are key players in the pathogenesis of RA. Additionally, liposomal DEX can induce the expression of anti-inflammatory cytokines like interleukin-10 (IL-10), which has significant anti-inflammatory and immunoregulatory properties. The findings suggest that liposomal DEX represents a promising candidate for effective and safe RA therapy, with the potential to improve the management of this debilitating disease by providing targeted delivery and sustained release of the drug.

Generating MVA-Vector Vaccine Candidates and Testing Them in Animal Models.

Modified Vaccinia Virus Ankara (MVA) is a highly attenuated and replication-deficient vaccinia virus developed through serial passages in chicken embryo fibroblasts (CEF). MVA is increasingly used in biomedicine for vaccine development in preclinical and clinical studies in humans. Major benefits of MVA include a well-established record in clinical safety, long-standing experience in genetic engineering of the virus, a large data set demonstrating efficacy in preclinical models with the capacity to induce both protective antigen-specific antibody and cellular immune responses, and the availability of virus production under Good Manufacturing Practice (GMP) suitable for industrial scale amplification. In this chapter, we describe established state-of-the-art protocols for generating, amplifying, and purifying recombinant MVA viruses, including possible vector viruses for further investigations as well as clinical evaluation.

Low dose Adenoviral Vammin gene transfer induces myocardial angiogenesis and increases left ventricular ejection fraction in ischemic porcine heart

This preliminary study investigated if VEGFR-2 selective adenoviral Vammin (AdVammin) gene therapy could induce angiogenesis and increase perfusion in the healthy porcine myocardium. Also, we determined using a clinically relevant large animal model if AdVammin gene therapy could improve the function of a chronically ischemic heart. Low doses of AdVammin (dose range 2 × 109–2 × 1010 vp) gene transfers were performed into the porcine myocardium using an endovascular injection catheter. AdCMV was used as a control. The porcine model of chronic myocardial ischemia was used in the ischemic studies. The AdVammin enlarged the mean capillary area and stimulated pericyte coverage in the target area 6 days after the gene transfers. Using positron emission tomography 15O-radiowater imaging, we demonstrated that AdVammin gene therapy increased perfusion in healthy myocardium at rest. AdVammin treatment also increased ejection fraction at stress in the ischemic heart, as detected using left ventricular cine angiography. In addition, we demonstrated successful in vivo imaging of enhanced angiogenesis using [68Ga]NODAGA-RGD peptide. However, AdVammin also increased tissue permeability and was associated with significant pericardial fluid accumulation, limiting AdVammin’s therapeutic potential and emphasizing the importance of correct dosage.

Pharmacological targeting of dopamine D1 or D2 receptors evokes a rapid-onset parkinsonian motor phenotype in mice.

Dopaminergic nigrostriatal denervation in Parkinson's disease (PD) disrupts the functional balance between striatal projecting neurons, leading to aberrant activity in the cortico-basal ganglia circuit and characteristic motor symptoms. While genetic and toxin-based animal models are commonly used to mimic PD pathology and behaviour, they have limitations when combined with circuit manipulation tools. This highlights the need for complementary approaches, particularly when combined with viral-based circuit targeting of specific neuronal subpopulations involved in PD circuit dysfunction. Here, we pursue a pharmacological approach targeting dopamine D1 or D2 receptors to induce dopamine deprivation and to replicate key motor symptoms in PD. We demonstrate a clear dose-dependent induction of parkinsonian motor behaviour by both a dopamine D1 receptor antagonist (SCH23390) and a D2 receptor antagonist (haloperidol). The motor phenotype is evaluated by considering relevant motor metrics in an open-field maze platform. The proposed parkinsonian pharmacological model constitutes an acute, flexible approach, which allows parallel brain circuit manipulations.

Fully Bioactive Nanodrugs: Stem Cell-Derived Exosomes Engineered with Biomacromolecules to Treat CCl4- and Extreme Hepatectomy-Induced Acute Liver Failure.

Acute liver failure (ALF) is a serious global disease characterized by rapid onset and high mortality. Currently, the clinical treatment of ALF faces considerable hurdles due to limited medication options and the scarcity of liver transplants. Despite biomacromolecules such as hepatocyte growth factor (HGF) and glutathione (GSH) having been applied for ALF symptom relief in the clinic, they still face substantial challenges including poor stability, difficulty in acting on intracellular targets, and inadequate therapeutic outcome. In this work, by taking advantage of the innate targeting and regenerative capabilities of mesenchymal stem cells (MSCs), we harnessed MSC-derived exosomes as natural bioactive carriers for the simultaneous delivery of HGF and GSH, forming a fully bioactive nanodrug termed HG@Exo. Impressively, the HG@Exo demonstrated potent therapeutic effects against both carbon tetrachloride (CCl4)- and extreme hepatectomy-induced ALF through multiple mechanisms, including regulation of oxidative stress, reduction of inflammation, and promotion of hepatocyte regeneration, which were facilitated by its inflammation-targeting to damaged liver tissues. Furthermore, an FDA-approved near-infrared fluorescent dye, indocyanine green (ICG), has been incorporated into the exosomes (HGI@Exo) to endow them with real-time in vivo tracking capability, which showed favorable liver accumulation of the HGI@Exo in both CCl4- and surgery-induced ALF animal models, providing crucial insights into their biodistribution and therapeutic efficacy. Overall, the presented fully bioactive nanodrugs with targeting and theranostic abilities hold significant promise for potentiating the therapeutic efficacy of biomacromolecules for the improved treatment of ALF and other inflammatory diseases.

Evaluation of a user-friendly CSDS cage apparatus for studying depressive-like behaviors in rodents.

Previously, a chronic social defeat stress (CSDS) model has been widely-adopted for assessing depressive-like behaviors in animals. However, there is still room for improvement in the CSDS model to safeguard study accuracy and the welfare of lab rodents. Our study team developed a novel, standardized apparatus to induce CSDS in rodents and assessed the model's practical adaptability. An innovative CSDS cage apparatus and water bottle was designed. To evaluate the effectiveness of the newly developed tools, a variety of animal models, including the tail suspension test (TST), sucrose preference test, forced swimming test (FST), novelty-suppressed feeding test, female urine sniffing test, and open field test (OFT), were adopted to assess depressive-like behaviors in mice. Fluoxetine treatment was also administered to observe the reversal effect, as part of the validation. The CSDS cage apparatus resulted in the manifestation of depressive-like behaviors in the model mice. Significant reductions in sucrose preference and urine sniffing time were observed, while the OFT revealed decreased central zone total distance, residence time, and frequency of entry. Moreover, increased immobility was found in the FST and TST. Fluoxetine treatment was found to successfully reverse the modeling effect. The CSDS cage apparatus was validated for enhanced usability and addressed the previous challenges of water bottle leakage and lab rodent welfare issues. The consistent results from multiple behavioral tests also supported real-world application of the apparatus, offering researchers a promising alternative to conventional rodent cages.

Osteoblast-derived exosomal miR-140-3p targets ACER2 and increases the progression of prostate cancer via the AKT/mTOR pathway-mediated inhibition of autophagy.

Advanced prostate cancer (aPCa) often results in bone metastases (BM). However, the mechanism underlying its progression and metastasis to bones remains unclear. Therefore, we examined whether exosomal miR-140-3p affects prostate cancer (PCa) progression. We obtained from cell lines, clinical data analyses, and animal models consistently provide important evidence. Patients with PCa having BM had higher miR-140-3p expression in their serum exosomes than those without BM. Clinical investigations have manifested that the exosomal miR-140-3p overexpression connects with serum prostate-specific antigen (PSA) levels and Gleason grade in patients with PCa. Osteoblast-derived exosomal miR-140-3p targeting ACER2 activates the AKT/mTOR pathway invitro, inhibits autophagy, and promotes PCa cell proliferation, invasion, and migration. miR-140-3p significantly increased tumorigenesis and metastasis of LNCaP invitro. Bone metastatic PCa tissues exhibited elevated levels of miR-140-3p, p-GSK3, p-mTOR, p62, p-AKT (S473), and p-AKT (T308) contrasted with non-BM tissues. Moreover, their expression was intensified in the metastatic bone tissues. However, ACER2 and LC3 II showed opposite expression patterns. Based on our study outcomes, the evidence suggests that osteoblast-derived miR-140-3p inhibition of autophagy through the AKT/mTOR pathway is involved in PCa progression. Osteoblast-secreted exosomal miR-140-3p activates the AKT/mTOR pathway by targeting ACER2, inhibiting autophagy, and promoting the progression of PCa cells invitro. Moreover, miR-140-3p induces the progression and metastasis of PCa invivo.

Defining the extracellular matrix in non-cartilage soft-tissues in osteoarthritis: a systematic review.

Extracellular matrix (ECM) is a critical determinant of tissue mechanobiology, yet remains poorly characterized in joint tissues beyond cartilage in osteoarthritis (OA). This review aimed to define the composition and architecture of non-cartilage soft joint tissue structural ECM in human OA, and to compare the changes observed in humans with those seen in animal models of the disease. A systematic search strategy, devised using relevant matrix, tissue, and disease nomenclature, was run through the MEDLINE, Embase, and Scopus databases. Demographic, clinical, and biological data were extracted from eligible studies. Bias analysis was performed. A total of 161 studies were included, which covered capsule, ligaments, meniscus, skeletal muscle, synovium, and tendon in both humans and animals, and fat pad and intervertebral disc in humans only. These studies covered a wide variety of ECM features, including individual ECM components (i.e. collagens, proteoglycans, and glycoproteins), ECM architecture (i.e. collagen fibre organization and diameter), and viscoelastic properties (i.e. elastic and compressive modulus). Some ECM changes, notably calcification and the loss of collagen fibre organization, have been extensively studied across osteoarthritic tissues. However, most ECM features were only studied by one or a few papers in each tissue. When comparisons were possible, the results from animal experiments largely concurred with those from human studies, although some findings were contradictory. Changes in ECM composition and architecture occur throughout non-cartilage soft tissues in the osteoarthritic joint, but most of these remain poorly defined due to the low number of studies and lack of healthy comparator groups.

Bioluminescence Imaging to Study Recombinant Orthopoxvirus Infection in Animal Models.

Bioluminescent images of viral replication in live animals (in vivo) reveal disease dynamics and effects of medical countermeasures over time. After selecting an appropriate orthopoxvirus animal model for the study, a recombinant virus with the firefly luciferase gene inserted in the genome is used to infect the animals. On the day of bioluminescent imaging, the substrate, D-luciferin, is prepared; animals are sedated and injected with the substrate and IVIS imager is utilized; various bioluminescent images are acquired; then animals recover and are able to continue in the study. Ex vivo imaging can also be completed after animals are euthanized at experimental endpoint. This approach allows real-time imaging of viral kinetics within an animal, and analysis of images can provide an additional quantitative measure throughout the study. Bioluminescent imaging not only provides scientific benefits but also benefits to animal welfare. For these reasons, bioluminescent imaging should be considered for any in vivo orthopoxvirus study.

Rat models of frozen shoulder: Classification and evaluation.

Frozen shoulder (FS), also known as adhesive capsulitis, is a condition that causes contraction and stiffness of the shoulder joint capsule. The main symptoms are persistent shoulder pain and a limited range of motion in all directions. These symptoms and poor prognosis affect people's physical health and quality of life. Currently, the specific mechanisms of FS remain unclear, and there is variability in treatment methods and their efficacy. Additionally, the early symptoms of FS are difficult to distinguish from those of other shoulder diseases, complicating early diagnosis and treatment. Therefore, it is necessary to develop and utilize animal models to understand the pathogenesis of FS and to explore treatment strategies, providing insights into the prevention and treatment of human FS. This paper reviews the rat models available for FS research, including external immobilization models, surgical internal immobilization models, injection modeling models, and endocrine modeling models. It introduces the basic procedures for these models and compares and analyzes the advantages, disadvantages, and applicability of each modeling method. Finally, our paper summarizes the common methods for evaluating FS rat models.

Evaluation of Vaccinia Virus Infection in Mice Using Two-Reporter Recombinant Virus.

The family Poxviridae comprises multiple viruses with large double-stranded (ds) DNA genomes that can infect numerous vertebrate and invertebrate hosts, including humans. The development of genetic engineering methods for Vaccinia virus (VACV), the prototypic member in the family, have allowed the manipulation of the genomes of poxviruses for the generation of recombinant (r)VACV expressing easily traceable luciferase and/or fluorescent reporter genes. These recombinant viruses have significantly contributed to progress in the field of poxvirus research and accelerated the development of novel prophylactic vaccines and therapeutic antiviral treatments. Recently, we described two reporter rVACV expressing luciferase (Nluc) and fluorescent (GFP or Scarlet) proteins to easily track viral infections in different systems, overcoming the limitations associated with the use of rVACV expressing a single luciferase or fluorescent reporter gene. Here, we describe the experimental procedures to carry out in vitro, in vivo and ex vivo studies using these novel bireporter-expressing rVACV, which also represent an excellent option to study the biology of VACV, including the use of these reporter viruses for testing new antivirals and vaccines, using cultured cells and/or well-characterized animal models of infection.