The autoimmune response directed against pancreatic β cells is the most essential pathogenic process in type 1 diabetes (T1D) in humans. Spontaneous animal models of T1D greatly contribute to our understanding of the disease pathogenesis and therapeutic options. Amongst many disease models, a significant proportion of T1D research is performed on multiple low dose streptozotocin induced diabetes in experimental animals, in parallel. Here, we discuss advantages of this model for contemporary T1D research. Additionally, challenges and perspectives for further improvement of the model are presented.
Background: Diabetic retinal neuropathy (DRN) leads to significant visual impairment; however, no existing animal model fully replicates its neural alterations, and inconsistent induction protocols with high mortality rates hinder long-term investigations.
Methods: Adult male rabbits were randomly assigned to four experimental groups, each receiving a single intravenous injection of varying doses of alloxan and one control group. The safety and efficacy of alloxan in inducing diabetes were evaluated to determine the optimal dose. At 9 weeks following injection with alloxan, retinal function was assessed using full-field electroretinography (ERG) and visual evoked potentials (VEPs). Retinal structure was examined in rabbits using spectral-domain optical coherence tomography (SD-OCT), Optos ultra-widefield (Optos UWF) false-color imaging, and widefield fundus fluorescein angiography (WF-FFA).
Results: Rabbits in the 80 mg/kg alloxan group exhibited fewer complications, lower mortality, and a higher model success rate compared to other groups. At 9 weeks post-injection, these rabbits demonstrated significantly elevated hemoglobin A1c and total cholesterol (p < 0.05) relative to controls. ERG revealed statistically significant reductions in oscillatory potential and b-wave amplitudes (p < 0.05), while VEP indicated decreased P2 amplitude (p < 0.001) and prolonged P2 latency (p < 0.05). SD-OCT, Optos UWF imaging, and WF-FFA demonstrated no significant changes in vascular abnormalities. Additionally, Hematoxylin and Eosin staining revealed retinal swelling (p < 0.05), and immunofluorescence confirmed glial activation and neuronal loss.
Conclusions: A single intravenous injection of 80 mg/kg alloxan effectively and safely induced DRN in rabbits, resulting in neural retina damage, thereby establishing this model as an ideal model for DRN research.
Background: Diabetes mellitus (DM) is a prevalent chronic metabolic condition characterized by high blood sugar levels, resulting from insufficient insulin production or ineffective insulin use, posing substantial global health issues. Research on the relationship between glycemic status and the ratio of neutrophils to lymphocytes (NLR) and monocytes to lymphocytes (MLR) is limited. This study aimed to fill these knowledge gaps by examining the connection between DM and inflammatory markers within the Asir region.
Methods: Data from 3545 participants were retrospectively analyzed. The dataset, gathered between 2021 and 2023, comprises 38 laboratory tests obtained from the Future Lab Pioneer database. The study's inclusion criteria focused on diabetes profile tests (glycated hemoglobin [HbA1c] and fasting blood glucose [FBG]) and manually computed inflammatory markers (NLR and MLR), which were stratified by age and sex.
Results: This study demonstrated significant differences in NLR levels compared with FBG levels across all adult age groups and adult female participants (p < 0.0001), as well as among all elderly age groups (p = 0.0006) and elderly women (p = 0.01). MLR levels were significant in all adult age groups (p = 0.04) and in adult women (p = 0.02). When NLR and MLR were compared to HbA1c levels, a significant difference in the mean NLR was found in adult women (p = 0.005). Additionally, the mean MLR levels were significant in all adult age groups (p = 0.04) and adult women (p = 0.02).
Conclusion: Although a larger sample size is necessary for this research, the results indicate that NLR and MLR could serve as valuable indicators for evaluating inflammation in people with disrupted glucose metabolism, particularly in adult and female populations.
Dysphagia is a common complication of stroke, Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). The construction of animal models of dysphagia is an important way to explore its pathogenesis and treatment. At present, the animal models of dysphagia mainly include rodents, nonhuman primates, and other mammals, such as pigs and dogs. This review systematically summarizes the establishment and evaluation of dysphagia animal models in stroke, PD, and ALS in three kinds of experimental animals, providing a basis for the selection of appropriate animal models of dysphagia.
This review focuses on rat models for studying the short-term and long-term effects of mild and severe hypoglycemia. We explored the physiological mechanisms to understand the consequences of hypoglycemia in rat experimental models. This study aims to investigate the therapeutic potential of phytotherapeutic agents and their efficacy in mitigating the adverse effects of hypoglycemia. Insights from our planned research will be beneficial in improving quality of life for individuals at risk of episodes of low blood sugar. Optimizing hypoglycemic rat models for research requires selecting a suitable experimental model that will be susceptible to hypoglycemia induction, effective monitoring of blood glucose levels, and maintaining a high survival rate throughout the required experimental duration.
The subcutaneous air pouch model has been used extensively to study the pathophysiology of inflammatory conditions such as joint diseases and the potential efficacy of pharmacological treatments in vivo. Delivery of air between the subcutaneous and dermal layer of the intra-scapular zone of the rodent generates an environment analogous to the synovial joint space. Introduction of monosodium urate crystals or calcium pyrophosphate crystals into the air space produces a sterile acute inflammatory response mimicking clinical gout and pseudogout, respectively. The inflammatory response can be quantitatively and robustly evaluated by measuring leukocyte infiltration, inflammatory cytokine production, eicosanoid release, complement activation and reactive oxygen species generation. Despite the utility of this model, great variation exists within the literature regarding the design, sampling time points, and endpoints measured. This systematic review summarizes the current literature on the subcutaneous air pouch model studying monosodium urate or calcium pyrophosphate crystals and provides recommendations for standardizing and improving the reliability and validity of this model. Standardizing the experimental approach would improve inter-study comparability, increase the internal validity of studies and reproducibility of results, and ultimately improve the understanding of gout and pseudogout and accelerate the discovery of new pharmacological therapies.
Experimental mice play a critical role in biomedical research. The phenotype and application of different substrains vary due to genetic differentiation and variation. To ensure validity and reliability of results, it is imperative to adhere to standardized experiments and controls. This paper objectively reviews the origin, differentiation, and phenotypic and genetic differences between the C57BL/6 and BALB/c mouse substrains. Furthermore, an optimal selection strategy is proposed based on the genetic quality control technology to facilitate the precise application of these two mouse substrains.
Background: Existing remedial approaches for relieving neuropathic pain (NPP) are challenging and open the way for alternative therapeutic measures such as electroacupuncture (EA). The mechanism underlying the antinociceptive effects of repeated EA sessions, particularly concerning the regulation of the Adora3 receptor and its associated enzymes, has remained elusive.
Methods: This study used a mouse model of spared nerve injury (SNI) to explore the cumulative analgesic effects of repeated EA at ST36 (Zusanli) and its impact on Adora3 regulation in the spinal cord dorsal horn (SCDH). Forty-eight male mice underwent SNI surgery for induction of neuropathic pain and were randomly assigned to the SNI, SNI + 2EA, SNI + 4EA, and SNI + 7EA groups. Spinal cord (L4–L6) was sampled for immunofluorescence, adenosine (ADO) detection and for molecular investigations following repeated EA treatment.
Results: Following spared nerve injury (SNI), there was a significant decrease in mechanical withdrawal thresholds (PWTs) and thermal nociceptive withdrawal latency (TWL) in the ipsilateral hind paw on the third day post-surgery, while the contralateral hind paw PWTs showed no significant changes. On subsequent EA treatments, the SNI + EA groups led to a significant increase in pain thresholds (p < 0.05). Repeated EA sessions in SNI mice upregulated Adenosine A3 (Adora3) and cluster of differentiation-73 (CD73) expression while downregulating adenosine deaminase (ADA) and enhancing neuronal instigation in the SCDH. Colocalization analysis of Neun-treated cells revealed increased Adora3 expression, particularly in the SNI + 7EA group.
Conclusions: In conclusion, cumulative electroacupuncture treatment reduced neuropathic pain by regulating Adora3 and CD73 expression, inhibiting ADA and most likely increasing neuronal activation in the SCDH. This study offers a promising therapeutic option for managing neuropathic pain, paving the way for further research.
Backgroud: Intervertebral disc degeneration (IDD) is one of the common degenerative diseases. Due to ethical constraints, it is difficult to obtain sufficient research on humans, so the use of an animal model of IDD is very important to clarify the pathogenesis and treatment mechanism of the disease.
Methods: In this study, thirty 2-month-old mice were selected for operation to establish a coccygeal IDD model. The distal tail portion of the tail (beyond the 17th coccygeal vertebra) and a small piece of skin above the 8th coccygeal vertebra were excised, and the two incisions were brought together after flexion, and secured with sutures. The heights and signal intensities of the intervertebral discs (IVDs) were assessed using microcomputed tomography (μCT) and magnetic resonance imaging (MRI) at 0, 6, 12 weeks postoperatively. The overall tissue morphology, cell distribution and density, and extracellular matrix of the IVDs were also assessed using Hematoxylin and Eosin (HE), Safranin O-Fast Green and immunohistochemical staining.
Results: All mice in the experimental group survived after the operation, and there were no complications such as wound infection, tail necrosis and suture shedding. The experimental results demonstrated that the suturing method can successfully initiate IDD. Different severity levels of IDD can be induced by controlling the bending angle of the IVDs within the tail loop; however, for consistency, histologic and imaging results should be obtained at the same bending angle and looping period.
Conclusions: This IDD model is an effective method for studying the etiology and treatment of degenerative IVD disease.
Background: Recent research showed that the NLRP3 inflammasome was activated in the central nervous system of mice administered chronic ethanol (EtOH). Dictyophora polysaccharides (DIPs) are essential components of the valuable edible fungus Dictyophora, which has antioxidant properties that can delay the aging process of the body. This study aimed to investigate the roles of NLRP3 in chronic EtOH-induced cerebellar Purkinje cell (PC) degeneration and behavioral changes.
Methods: C57BL/6J normal and NLRP3 knockout mice were exposed to EtOH for 14 days. Dictyophora polysaccharide (DIP) and NLRP3 inhibitor were administered to the EtOH mice. The pathology and NLRP3-ASC-caspase-1 signaling pathway proteins were analyzed in EtOH mice cerebellar tissues and behavioral performance was assessed in the mice.
Results: In the EtOH mouse model, we observed increases in the NLRP3 inflammasome proteins, including NLRP3, ASC, caspase-1, mature IL-1β and pro IL-1β, loss of PCs, and motor coordination disorders. We found that DIPs could suppress the NLRP3-ASC-caspase-1 signaling pathway, and alleviate the motor deficits and cerebellar pathological changes in chronic EtOH mice. Next, we used MCC950, a NLRP3 inhibitor, and an NLRP3 knockout strategy to further verify the effects of NLRP3-ASC-caspase-1 signaling in chronic EtOH mice. MCC950 or NLRP3 knockout alleviated the EtOH-induced latency to decreases in fall time, increases in stride width and decreases in stride length. MCC950 or NLRP3 knockout also attenuated PC number loss and suppressed NLRP3 inflammation induced by EtOH. Taken together, pharmacologically or genetically inhibiting NLRP3 alleviated EtOH-induced cerebellar degeneration and behavioral deficits.
Conclusion: These findings indicated that DIPs might diminish EtOH-induced cerebellar degeneration and behavioral deficits through the NLRP3-ASC-caspase-1 signaling pathway, which provides a potential therapeutic target for the prevention and treatment of alcoholism and EtOH-induced cerebellar pathology.
Background: It is well recognized that developing new animal models, refining the existing mouse models, and thoroughly characterizing their features are essential for gaining a deeper understanding of rosacea pathogenesis and for advancing therapeutic strategies in this direction. Accordingly, we aimed to characterize the pathological features of a long-term LL-37-induced mouse model of rosacea and to compare the disease manifestations and pathophysiological characteristics between short-term and long-term LL-37-induced models. A key focus was to investigate differential gene expression and the underlying mechanisms of immune system dysregulation in these models.
Methods: We comparatively assessed skin lesion manifestations, the extent of inflammatory infiltration, sebaceous gland alterations, fibrosis, and angiogenesis in both models. Assessments were performed using photographic documentation, hematoxylin–eosin (HE) staining, Van Gieson's (VG) staining, immunohistochemistry, and Western blotting. Furthermore, we employed RNA sequencing to analyze differential gene expression in mouse skin. The RNA sequencing data were validated using immunofluorescence staining and Western blotting, with a specific focus on gene variations and mechanisms related to immune system dysregulation.
Results: Mice subjected to long-term LL-37 induction developed rosacea-like pathological features, including angiogenesis, thickened skin tissue, and sebaceous gland hypertrophy. In the short-term LL-37-induced model, immune dysregulation primarily involved the innate immune response. However, long-term LL-37 induction resulted in significant activation of both innate and adaptive immune responses.
Conclusion: The long-term LL-37-induced mouse model offers a valuable animal model for the detailed investigation of the pathological mechanisms driving moderate-to-severe rosacea with prolonged disease duration. Importantly, this model provides a significant experimental foundation for exploring the potential role of immune system dysregulation in rosacea pathogenesis.
Background: Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease marked by significant clinical and genetic heterogeneity, primarily caused by expanded CAG mutations in the ATXN2 gene. The unstable expansion of CAG repeats disrupts the genetic stability of animal models, which is detrimental to disease research.
Methods: In this study, we established a mouse model in which CAG repeats do not undergo microsatellite instability (MSI) across generations. A humanized ATXN2 cDNA with four CAA interruptions within 73 CAG expansions was inserted into the Rosa26 locus of C57BL/6J mice. A 23 CAG control mouse model was also generated to verify ATXN2 integration and expression.
Results: In our model, the number of CAG repeats remained stable during transmission, with no CAG repeat expansion observed in 64 parent-to-offspring transmissions. Compared with SCA2-Q23 mice, SCA2-Q73 mice exhibited progressive motor impairment, reduced Purkinje cell count and volume (indicative of cell atrophy), and muscle atrophy. These observations in the mice suggest that the behavioral and neuropathological phenotypes may reflect the features of SCA2 patients. RNA-seq analysis of the gastrocnemius muscle in SCA2-Q73 mice showed significant changes in muscle differentiation and development gene expression at 56 weeks, with no significant differences at 16 weeks compared to SCA2-Q23 mice. The expression level of the Myf6 gene significantly changed in the muscles of aged mice.
Conclusion: In summary, the establishment of this model not only provides a stable animal model for studying CAG transmission in SCA2 but also indicates that the lack of long-term neural stimulation leads to muscle atrophy.
Background: Glioblastoma (GBM) is a highly aggressive brain tumor characterized by aberrant angiogenesis and an immunosuppressive microenvironment. Pericytes are aberrantly recruited but their spatiotemporal roles and molecular changes remain unclear. This study investigated platelet-derived growth factor receptor beta-positive (Pdgfrb+) pericyte dynamics and reprogramming in GBM vasculature.
Methods: We generated GL261-Luc and GL261-CFP glioblastoma cells via lentiviral transduction and established two transgenic models. (1) For pericyte labeling, Ai14 reporter mice was crossed with PDGFRβ-P2A-CreERT2 mice for tdTomato-specific lineage tracing (PT mice). (2) For conditional ablation, we generated inducible Pdgfrb-expressing cell ablation models (PT mice was crossed with ROSA-DTA mice). An intravital imaging platform (FITC-dextran/CFP/tdTomato + two-photon microscopy) tracked pericytes, vessels, and tumor cells, while FACS-sorted Pdgfrb+ cells from GBM and normal brain were analyzed by LC–MS/MS proteomics.
Results: Cre-mediated ablation of Pdgfrb-expressing cells revealed stage-dependent effects on GBM growth: early ablation inhibited progression while late ablation promoted it. Pericytes undergo dual spatial reorganization in GBM: regional enrichment with pre-sprouting accumulation at the tumor-brain interface, and focal positioning with preferential localization at vascular branch points. Concurrently, GBM vasculature displayed simplified branching, dilation, and pericyte remodeling (shorter processes, higher density). Proteomics revealed 1426 altered proteins, with upregulated proliferation pathways (e.g., matrix metallopeptidase 14 [Mmp14], lysyl oxidase like 2 [Loxl2]) and downregulated homeostasis functions (e.g., transforming growth factor beta 1 [Tgfb1]), validated by scRNA-seq in human GBM.
Conclusions: This study demonstrates that during early GBM progression, pericytes actively drive tumor angiogenesis through molecular reprogramming toward proliferative and pro-angiogenic phenotypes, with the integrated imaging-proteomics framework revealing potential therapeutic targets for disrupting pericyte-mediated vascular remodeling.
Background: The absence of well-established immunosuppressed rabbit models poses a significant hurdle in xenograft experiments. Tacrolimus has been identified as a highly promising immunosuppressive agent for rabbits. However, determining the optimal dosage and route of administration to minimize toxicity while maintaining efficacy remains challenging.
Methods: In this study, we investigated the effect of orally administered tacrolimus in rabbits, with an aim to achieve a whole blood target trough level of 3–10 ng/mL, and looked at signs of tissue rejection after the transplantation of a human nerve conduit to repair a severed fibular nerve. An oral dosage range of 0.25–1.5 mg/kg/d was studied for up to 1 year in 63 New Zealand rabbits.
Results: We demonstrated the feasibility of long-term grafting in rabbits while maintaining safe immunosuppression, with side effects mainly limited to diarrhea. Customizing the administered dose proved crucial for graft efficacy and low toxicity, which translated into 100% individual survival. We suggest an oral tacrolimus dose of 1.0–1.5 mg/kg depending on individual heterogeneity and recommend to implement a close therapeutic drug monitoring in the rabbits to maintain a whole blood tacrolimus trough level within the range of 5–12 ng/mL, as levels below 5 ng/mL showed signs of inflammation in the graft.
Conclusion: The oral administration of tacrolimus enabled efficient immunosuppression of rabbits over a 1-year period without significant side effects or loss of animals.
Accurate macaque paternity identification is of great significance in various fields, yet relevant research remains scarce. Our study aimed to screen effective microsatellite markers for macaque paternity testing. Initially, 300 microsatellite markers were randomly selected from the genome of the crab-eating macaque (Macaca fascicularis), and 12 highly polymorphic tetra-nucleotide repeat markers were identified. These markers' genetic parameters and exclusion probabilities in both crab-eating and rhesus macaque (Macaca mulatta) populations were calculated, meeting the paternity testing requirements for both species. To validate the markers, 16 crab-eating macaque and 10 rhesus macaque families with known pedigrees were randomly chosen for testing. The genotypes of the 12 markers in the macaques' offspring could be traced back to their parents, confirming the accuracy and applicability of the marker combination for paternity identification in both macaque species.
Lung ischemia–reperfusion injury (LIRI), an acute lung injury syndrome triggered by lung transplantation or distal organ ischemia, has long been a difficult and hot issue in clinical research. In this study, we proposed a simple and less invasive reversible LIRI surgical protocol, achieved by improving the mouse left hilar entrapment model, which significantly improved the operability of the experiment and the reproducibility of the results. The protocol achieves precise control of the ischemic and reperfusion processes by visualizing transoral intubation, using reversible ligation of live knots to clamp the left hilar, and temporary closure of the thoracic cavity during ischemia. The reversible survival model we constructed not only provides a reliable tool to study the cellular and molecular mechanisms of LIRI but also can be used to assess the stage of injury regression, experimental pneumonia, and survival in mice. In addition, it simplifies the lung portal separation clamping operation for reversible clamping and provides an easy-to-learn visual tracheal intubation method that can be quickly mastered and replicated by beginners for consistent and reliable results.
Remembrance activities can support the Culture of Care (CoC) in Laboratory Animal Science (LAS) not only by promoting a culture of respect, gratitude and thankfulness for animal life but also by helping the emotional processing and healing of lab animal researchers and animal facility staff. Even though remembrance activities are practiced in many parts of the world, we did not come across any reported cases in Sri Lanka before 2022. Therefore, here, we report on the various remembrance activities and practices observed within our local scientific community.