Animal models and experimental medicine最新文献

Vitamin D, with its diverse molecular pathways and immunomodulatory properties, has become a crucial tool in the prevention and treatment of various cancers. It controls angiogenesis, apoptosis, differentiation, and cellular proliferation, inhibiting cancer through immune surveillance, DNA repair, and tumor suppression genes. Additionally, vitamin D signaling impacts tumor growth and metastasis in various cancer types by interacting with key oncogenic pathways like Wnt/β-catenin, NF-κB, PI3K/Akt, and p53. This review demonstrates the molecular and therapeutic implications of vitamin D in oncology, focusing on its potential as a safe, adjuvant treatment method. It emphasizes the role of vitamin D in epigenetic modification, its impact on tumor microenvironment, and its synergistic benefits when combined with immune checkpoint inhibitors and chemotherapeutic drugs. Despite promising results, genetic variations in the VDR gene continue to cause issues with bioavailability, ideal dosage, and interindividual response variability. The review also proposes future research on vitamin D's potentiality as a therapeutic adjuvant in various malignancies, including colorectal, prostate, and breast cancers, and suggests the development of non-calcemic vitamin D analogs and the incorporation of vitamin D-based methods into personalized oncology treatments.

Background: The precise insertion of large DNA fragments (>3-5 kb) remains one of the key obstacles in establishment of genetically modified murine models.

Methods: A 21 kb large DNA fragment containing three tandemly linked copies of the human HRAS gene was inserted into the genome of C57BL/6J mouse, generating a mouse model designated as KI.C57-ras (or named NF-hHRAS). Whole-genome sequencing and Sanger sequencing were utilized to it confirm precise insertion and copy number. The stability of transgene expression among different generations was verified from multiple aspects using by digital PCR, western blot and DNA sequencing. To assess tumor susceptibility in the mouse model, N-Nitroso-N-methylurea (MNU) was administered at a dosage of 75 mg/kg. Histopathological examinations were conducted using hematoxylin and eosin (H&E) staining.

Results: The HRAS DNA fragment was inserted into mouse chromosome 15E1 site, locating between 80 623 202 bp and 80 625 020 bp. NF-hHRAS mice exhibited stable inheritance and displayed consistent phenotypes across individuals. Moreover, this mouse model exhibited a high susceptibility to carcinogens. Upon administration of MNU the earliest mortality onset was earlier than that of wild-type littermates (day 65 vs. day 78 for male and day 56 vs. day 84 for female). Notably, 100% of the NF-hHRAS transgenic mice developed tumors, with approximately 84% of male NF-hHRAS mice exhibiting specific tumor types, such as squamous cell carcinoma or squamous cell papilloma, which was consistent with the previously reported carcinogenic rasH2 mouse model. The types of tumors and the target organs exhibited diversity in NF-hHRAS mice, while the spontaneous tumor incidence remained low (1/50).

Conclusions: The NF-hHRAS mice demonstrated excellent genetic stability, a reproducible phenotype, and high susceptibility to carcinogens, indicating their potential utility in non-clinical safety evaluations of drugs as per the S1B guidelines issued by the ICH (The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use).

Robust preclinical models of transgender male (TGM) gender-affirming hormone therapy (GAHT) can inform clinicians of the isolated effects of GAHT; however existing models vary significantly in approach. We aimed to assess existing methodology and how it influences circulating sex-hormone levels in rodent models of TGM GAHT to provide recommendations of best practise. PubMed, Embase, and Scopus databases were systematically searched for studies that investigated GAHT in rodent models and were published from inception to the 1st of August 2024. Study characteristics and methodology were extracted and compared. Post-intervention circulating sex hormone concentrations were the primary outcome used to determine whether successful gender affirming hormone therapy had been achieved. Sixteen experimental rodent studies were included. Studies were performed on mice (n = 11) and rats (n = 5). Subcutaneous (SC) pellets and SC silastic implants were featured in some studies but weekly SC injections of testosterone enanthate was the preferred method. Sesame oil was the preferred solvent for injected testosterone formulations. Weekly doses of ~450 μg (mice) and ~420-900 μg (rats) consistently induced the testosterone levels of the male counterpart. Similarly, 10 mg of unesterified testosterone in a SC silastic implant in mice or 10 mg/100 g in rats were also successful methods. Most studies administered hormones for 6-8 weeks before performing post-treatment assessments. This review demonstrates that methods largely varied across studies and successfully identifies the effective methodological approaches that improve the reproducibility and accuracy of preclinical models. Representing an integral step forward to bridging gaps in preclinical transgender healthcare research.

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.