Animal models and experimental medicine最新文献

Background: Although widely used, the rat model remains poorly transferable to humans for peripheral nerve regeneration studies. The rabbit is a much better choice from an anatomical perspective. However, it remains little used due to the lack of available literature. The aim of this article is to demonstrate the feasibility and effectiveness of an electrophysiological protocol combined with a motor function assessment to analyze nerve repair.

Methods: Ten white New Zealand rabbits underwent a 4 cm transection of the fibular nerve. Autograft regeneration over 36 weeks was compared to non-repaired controls. The compound muscle action potential (CMAP) was recorded in the tibialis anterior and the extensor digitorum brevis. An electromyogram (EMG) was obtained after needle insertion and resting muscle activity recording. The electrophysiological results were compared to the toe spread index (TSI), which assesses the motor functional recovery promoted by fibular nerve regeneration.

Results: The autograft group regeneration starts between weeks 18 and 21 and normal EMG was observed around the 30th week. These electrophysiological results were compared to the well-defined toe spread reflex. This motor test showed a significant functional return of 59% at 36 weeks (p < 0.05). Rabbits regain nearly 80% of their muscle mass.

Conclusion: Nerve conduction allows detection of nerve regeneration of the muscle while electromyography indicates when muscle activity returns to normal. These studies are reliable and non-invasive techniques to evaluate fibular nerve regeneration in the rabbit's hindlimb. Nonetheless, it is necessary to have qualified personnel, since inter-manipulator variations have been observed.

Background: The investigation of ovarian development, dysfunction, and aging is essential for female reproductive health. Despite extensive research on the cellular functions of Brefeldin A (BFA) as an intracellular transport inhibitor, its specific effects and mechanisms on ovarian development/aging remain inadequately understood.

Methods: Mice and porcine oocytes/granulosa cells (GCs) were treated with BFA. Morphological and omics analyses (including Western blot, real-time polymerase chain reaction (RT-PCR), transcriptomics, and metabolomics) were conducted.

Results: In 3-week-old female mice, BFA treatment significantly suppressed oocyte maturation, induced apoptosis, and increased estradiol and LH levels. This treatment upregulated apoptosis-related genes while downregulating proliferation-associated genes. Additionally, BFA elevated senescence markers (p21 and p26) and decreased the activity of the longevity gene SIRT6. In porcine oocytes, BFA reduced the maturation rate and lowered mRNA levels of key maturation-related genes, LHX8 and GDF9. In porcine GCs, BFA increased apoptosis and upregulated genes such as Caspase-3, BAX, and P21, while downregulating genes associated with proliferation and longevity. Similar effects were observed in 12-month-old female mice, indicating consistency across age groups. Metabolomic analysis in these mice revealed that BFA primarily impacted pathways related to steroid biosynthesis, ovarian steroidogenesis, and estrogen signaling. Transcriptomic analysis in 12-month-old female mice further demonstrated that BFA disrupted ovarian function through multiple mechanisms, including modulation of the GnRH signaling pathway, activation of the FOXO pathway, and interference with meiosis-related gene expression.

Conclusion: Our findings are pivotal for advancing the understanding of ovarian aging, dysfunctions, and diseases, and ultimately facilitate addressing BFA's potential adverse effects on reproductive health/aging.

Xenotransplantation, that is, the transplantation of cells, tissues, and organs between species, is a rapidly developing alternative to classical transplantology in human medicine. Since the first successful kidney transplant in 1954, transplant medicine has made enormous progress. Until today, there are numerous patients worldwide waiting for an organ to be transplanted, and the number is still increasing, whereas the number of available organs is decreasing. One promising solution to this critical issue is the breeding of genetically modified animals as potential donors, which has gained the attention of scientists over the past two decades. Recent advancements in xenotransplantation have led to successful transfers of genetically modified pig organs into human recipients. Particularly, pig kidneys have been transplanted into living humans, demonstrating normal postsurgical function. Additionally, pig lungs functioned for 9 days in a brain-dead individual without experiencing hyperacute rejection. Furthermore, the successful xenotransplantation of pig hearts into living persons, exhibiting life-sustaining graft function, underscores significant progress toward clinically viable xenotransplants. This review provides an updated overview of the animal species and models used in xenotransplantation, with particular emphasis on the potential of transgenic pigs as donors. It discusses the process involved in producing the aforementioned animals, including the methods used to modify their genome. Particular attention is paid to immunological and genetic barriers, as well as zoonotic risks, and the possibilities and limitations of this technology. Although xenotransplantation is still in its experimental stage, it may play a crucial role in saving patients' lives in the future.

Background: The Vietnamese swine represents a promising animal model due to its anatomical, physiological, and pathophysiological similarities to humans. Notably, the arrangement of lobes and ducts in the mammary glands is highly comparable to that of humans and is histologically indistinguishable. Leveraging these advantages through the chemical induction of carcinogenesis in this model offers a robust approach to mimic human exposure to carcinogenic compounds.

Methods: This study elaborates on a protocol for developing a representative model of MNU-induced invasive breast carcinoma in three Vietnamese swine, validated histologically and immunologically. It evaluates not only the tissue similarity with humans, but also the development of chemically induced mammary tumors in an immunologically competent animal. Moreover, this study addresses the existing gap in histological knowledge regarding mammary tissue in the porcine model.

Results: Our findings suggest that this model encompasses the full spectrum of cancer. It incorporates the key elements of a tumor microenvironment that enable tumor growth and propagation, such as immune cells, blood vessels, fibroblasts, extracellular matrix, fatty acids, and signaling molecules.

Conclusions: This model offers significant potential to advance the understanding of cancer pathogenesis and facilitate the development of innovative therapeutic strategies by closely replicating human tumor biology.

Radiological or nuclear accidents can lead to serious outcomes for individuals exposed to ionizing radiation, with health effects that are either acute or delayed, deterministic or stochastic, depending on the effective dose of exposure. Mechanistically, ionizing radiation can inflict damage either directly on DNA or through oxidative stress, which may trigger a cascade of damages to tissues and organs. The development of effective radiation medical countermeasures is an unmet need and should be a top priority in preparing for radiation emergencies. This paper aims to address the critical questions of whether current countermeasures are available, what additional measures are needed, and what actions can be taken to enhance the development of radiation medical countermeasures from a systematic perspective.

In this study, we aimed to develop an in vivo electrophysiological bone-nerve preparation to record the activity of peripheral sensory neurons that innervate the murine tibia. A small nerve that innervates the tibial marrow cavity was identified in isoflurane-anesthetized C57BL/6 mice, and placed over a platinum hook electrode for extracellular recording. Whole-nerve activity was amplified, filtered and sampled at 20 kHz using PowerLab (ADInstruments). A cannula was placed into the marrow cavity to deliver mechanical stimuli (by pressurizing with injection of saline) and/or capsaicin. Optical stimulation was achieved by application of 473 nm blue light (1 Hz, 0.25–0.5 ms, 0–12.5 mW/mm) to the tibial marrow cavity in Wnt1-Cre; loxP-ChR2 mice. Murine bone afferent neurons responded to high threshold noxious mechanical stimulation, coded for the intensity of mechanical stimulation, could be sensitized by capsaicin, and did not suffer stimulus-evoked fatigue at 10-minute interstimulus intervals. Electrical and optical stimulation within the marrow cavity evoked action potentials with conduction velocities in the Aδ and/or C fiber range. These new approaches to recording the activity of bone afferent neurons will allow us to take advantage of transgenic and optogenetic tools to further our understanding of mechanisms that generate and maintain bone pain in the future.

The COVID-19 pandemic posed a challenge for clinical management of a new lung disease that was characterized by inflammation, endothelial cell dysfunction, and thrombosis, which occur after the replication phase of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are many laboratory models of active SARS-CoV-2 infection in mice, reflecting an acute lung injury in an otherwise healthy animal, but there is a lack of accurate animal models of the postviral inflammatory phase of the COVID-19 lung reflecting severe disease. The monocrotaline (MCT)–treated rat is a widely used laboratory model of pulmonary hypertension (PH). Not often discussed, however, are the observed changes in inflammation, edema, fibrosis, and microthrombosis in the lung prior to PH. At the cellular level, there is loss of pneumocytes and endotheliopathy, and at the molecular level the MCT rat lung is characterized by a pro-inflammatory cytokine profile, namely elevated interleukin 6, transforming growth factor β and tumor necrosis factor, M1 macrophage phenotype, and dysregulation of the angiotensin converting enzyme (ACE)/ACE2 balance. The systems-level pathophysiology of the MCT-treated rat includes progressive cardiopulmonary dysfunction. The MCT-treated rat clearly differs from the COVID-19 lung in terms of the triggers for pathology, but there are many parallels apparent in both the MCT-treated rat and the COVID-19 lung. The MCT-treated rat lung as a model of the COVID-19 lung may provide an in-depth understanding of the factors that drive the lung to more severe pathology, treatments that benefit lung recovery, or the factors that prove a useful research platform for future emerging respiratory threats of similar pathology.

Background: SEC16A is a pivotal protein that facilitates the transport of proteins from the endoplasmic reticulum to the Golgi apparatus. Utilizing the protein structure function database, a potentially pathogenic mutation site (NM_014866.1: c.4606C>G(p.L1536V)) was pinpointed within the conserved central core region of the human SEC16A protein, a component integral to the COPII complex assembly.

Methods: Leveraging information on human gene mutations and aligning human and mouse protein amino acid sequences, the Sec16aL1551V/L1551V mouse model was successfully developed using CRISPR/Cas9 technology.

Results: Two behavioral experiments, namely novel object recognition and cued fear conditioning, revealed that Sec16aL1551V/L1551V mice demonstrated a phenotype of neurological impairment, evidenced by diminished abilities in learning and memory. Furthermore, while undergoing tail suspension, the Sec16aL1551V/L1551V mice displayed a distinctive limb clasping behavior, a characteristic typically associated with mouse models of chronic neurodegenerative diseases.

Conclusion: The Sec16aL1551V/L1551V mouse model developed in this study providing a powerful tool for better understanding of the pathogenic mechanisms of Sec16a gene mutations in brain dysfunction diseases.