Animal models and experimental medicine最新文献

Background: The biomechanical environment created by suture-button fixation Latarjet is conducive to the healing and shaping of the transplanted coracoid, but its mechanism remains unclear. The latest research has found that the absence of stem cell chemokine (CXCL12) impeded bone regeneration in Sonic Hedgehog (SHH)-deficient animals. However, whether the biomechanical environment affects SHH and CXCL12 function has not been studied.

Methods: Rat fracture models were constructed to simulate stress environments under non-load-bearing and load-bearing conditions. The fracture healing and shaping, as well as the expression levels of SHH and CXCL12, were assessed through gross viewing, micro-computed tomography (micro-CT), and histochemical staining.

Results: Under flexible fixation, the relative bone volume (BV/TV) of rats exposed to the load-bearing stress environment was significantly higher than that of rats under a non-load-bearing stress environment (p ≤ 0.05). Adverse bone shaping was not observed in rats subjected to flexible fixation. The levels of SHH and CXCL12 in load-bearing rats exhibited significant elevation (p ≤ 0.05). Under a load-bearing stress environment, no significant difference was observed in the BV/TV between the flexible fixation group and the rigid fixation group (p ≥ 0.05), but there was excessive hyperplasia of the fracture callus in the rigid fixation group. The levels of SHH and CXCL12 in rats subjected to rigid fixation were significantly elevated (p ≤ 0.05).

Conclusions: Flexible fixation and load-bearing stress environment may contribute to bone healing and shaping by influencing the levels of SHH and CXCL12, suggested that this mechanism may be relevant to the healing and shaping of the transplanted coracoid after suture-button fixation Latarjet.

Background: Species of the genus Eimeria cause coccidiosis in chickens, resulting in a huge burden to the poultry industry worldwide. Eimeria tenella is one of the most prevalent chicken coccidia in China, and E. tenella infection causes hemorrhagic cecitis.

Methods: Using an established model of coccidiosis in chickens combined with necropsy, imaging of pathological tissue sections, and other techniques, we evaluated the gross and microscopic lesions of cecal tissue within 15 days after inoculation with sporulated oocysts and described the endogenetic developmental process and relationship between E. tenella infection and enteritis development in chickens.

Results: We observed three generations of merogony and gamogony in E. tenella. We observed gross lesions in the cecum from 84 hpi (hours post inoculation) and microscopic lesions from 60 hpi. The lesions in the cecum mainly exhibited hemorrhagic enteritis. Their severity increased with the onset of the second generation of merogony. The lesions began to alleviate by the end of the endogenous stages of E. tenella.

Conclusion: We show, for the first time, the complete observation of a series of changes in enteritis caused by 5 × 10³ E. tenella oocysts. This study provides reference materials for E. tenella research and pathological diagnosis.

Background: Zinc-finger E-box-binding homeobox-1 (ZEB1) is predominantly found in type-H vessels. However, the roles of ZEB1 and type-H vessels in steroid-induced osteonecrosis of the femoral head (SONFH) are unclear.

Methods: Human femoral heads were collected to detect the expression of ZEB1 and the levels of type-H vessels. Then, the SONFH model was developed by injecting C57BL/6 mice with lipopolysaccharide and methylprednisolone. Micro-computed tomography, angiography, double calcein labeling, immunofluorescence, immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blotting were performed to detect the expression of ZEB1, the Wnt/β-catenin pathway, type-H vessels, and the extent to which ZEB1 mediates angiogenesis and osteogenesis. Human umbilical vein endothelial cells were also used to explore the relationship between ZEB1 and the Wnt/β-catenin pathway.

Results: We found that ZEB1 expression and the formation of type-H vessels decreased in SONFH patients and in a mouse model. The number of vascular endothelial growth factors in the femoral heads also decreased. Moreover, the bone mineral density, trabecular number, mineral apposition rate, and expression of genes related to osteogenesis decreased. After ZEB1 knockdown, angiogenesis and osteogenesis decreased. However, the numbers of type-H vessels and the extent of angiogenesis and osteogenesis improved after activation of the Wnt/β-catenin pathway.

Conclusions: The ZEB1 expression decreased in SONFH, causing a decrease in type-H vessel, and it mediated angiogenesis and osteogenesis by regulating the Wnt/β-catenin pathway, ultimately accelerating the process of SONFH.

Premature ovarian failure (POF)is defined as the loss of normal ovarian function before the age of 40 and is characterized by increased gonadotropin levels and decreased estradiol levels and ovarian reserve, often leading to infertility. The incomplete understanding of the pathogenesis of POF is a major impediment to the development of effective treatments for this disease, so the use of animal models is a promising option for investigating and identifying the molecular mechanisms involved in POF patients and developing therapeutic agents. As mice and rats are the most commonly used models in animal research, this review article considers studies that used murine POF models. In this review based on the most recent studies, first, we introduce 10 different methods for inducing murine POF models, then we demonstrate the advantages and disadvantages of each one, and finally, we suggest the most practical method for inducing a POF model in these animals. This may help researchers find the method of creating a POF model that is most appropriate for their type of study and suits the purpose of their research.

Background: Native cartilage has low capacity for regeneration because it has very few progenitor cells. Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) and human umbilical cord-derived MSCs (hUC-MSCs) have been employed as promising sources of stem cells for cartilage injury repair. Reproduction of hyaline cartilage from MSCs remains a challenging endeavor. The paracrine factors secreted by chondrocytes possess the capability to induce chondrogenesis from MSCs.

Methods: The conditioned medium derived from chondrocytes was utilized to induce chondrogenic differentiation of hUCB-MSCs and hUC-MSCs. The expression levels of collagen type I alpha 1 chain (Col1a1), collagen type II alpha 1 chain (Col2a1), and SRY-box transcription factor 9 (SOX9) were assessed through quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunofluorescence (IF) assays. To elucidate the mechanism of differentiation, the concentration of transforming growth factor-β1 (TGF-β1) in the conditioned medium of chondrocytes was quantified using enzyme-linked immunosorbent assay (ELISA). Meanwhile, the viability of cells was assessed using Cell Counting Kit-8 (CCK-8) assays.

Results: The expression levels of Col2a1 and SOX9 were found to be higher in induced hUC-MSCs compared to those in induced hUCB-MSCs. The conditioned medium of chondrocytes contained TGF-β1. The CCK-8 assays revealed that the proliferation rate of hUC-MSCs was significantly higher compared to that of hUCB-MSCs.

Conclusions: The chondrogenic potential and proliferation capacity of hUC-MSCs surpass those of hUCB-MSCs, thereby establishing hUC-MSCs as a superior source of seed cells for cartilage tissue engineering.

Human-derived tumor models are essential for preclinical development of new anticancer drug entities. Generating animal models bearing tumors of human origin, such as patient-derived or cell line-derived xenograft tumors, is dependent on immunodeficient strains. Tumor-bearing immunodeficient mice are susceptible to developing unwanted disorders primarily irrelevant to the tumor nature; and if get involved with such disorders, reliability of the study results will be undermined, inevitably confounding the research in general. Therefore, a rigorous health surveillance and clinical monitoring system, along with the establishment of a strictly controlled barrier facility to maintain a pathogen-free state, are mandatory. Even if all pathogen control and biosafety measures are followed, there are various noninfectious disorders capable of causing tissue and multiorgan damage in immunodeficient animals. Therefore, the researchers should be aware of sentinel signs to carefully monitor and impartially report them. This review discusses clinical signs of common unwanted disorders in experimental immunodeficient mice, and how to examine and report them.

The present study aims to establish a reproducible large animal experimental unit using a minipig model to monitor cardiac function changes. A 90-min closed-chest balloon occlusion of the left anterior descending branch of the coronary artery was used to induce myocardial infarction in Pannon minipigs. To monitor the cardiac function, measurements were made by cardiac magnetic resonance imaging (cMRI), invasive pressure monitoring, and a Pulse index Continuous Cardiac Output (PiCCO) hemodynamic system at 0, 72, and 720 h during the follow-up period. End-diastolic and end-systolic volumes (EDV, ESV), left ventricular ejection fraction (LVEF) obtained by cMRI evaluation, global ejection fraction and aortic dP/dt_max obtained by the invasive method, were recorded and compared. The 72- and 720-h EDV data showed a significant increase (p = 0.012, <0.001) compared to baseline, and the Day 30 data showed a significant increase compared to Day 3 (p = 0.022). The ESV 72 h after the infarction showed a significant increase (p = 0.001) compared to baseline, which did not change significantly by Day 30 (p = 0.781) compared to Day 3. EDV and ESV were significantly negatively correlated with aortic dp_max, and ESV was significantly correlated with LVEF. For LVEF and dP_max, a significant (p < 0.001 and p = 0.002) worsening was demonstrated at Day 3 compared to baseline, which was no longer statistically detectable for LVEF at Day 30 (p = 0.141), while the difference for dP_max was maintained (p = 0.002). The complementary use of PiCCO hemodynamic measurements in large animal models makes the previously used methodologies more robust and reliable.

Background: In view of the ever-increasing representation of Staphylococcus spp. strains resistant to various antibiotics, the development of in vivo models for evaluation of novel antimicrobials is of utmost importance.

Methods: In this article, we describe the development of a fully immunocompetent porcine model of extensive skin and soft tissue damage suitable for testing topical antimicrobial agents that matches the real clinical situation. The model was developed in three consecutive stages with protocols for each stage amended based on the results of the previous one.

Results: In the final model, 10 excisions of the skin and underlying soft tissue were created in each pig under general anesthesia, with additional incisions to the fascia performed at the base of the defects and immediately inoculated with Staphylococcus aureus suspension. One pig was not inoculated and used as the negative control. Subsequently, the bandages were changed on Days 4, 8, 11, and 15. At these time points, a filter paper imprint technique (FPIT) was made from each wound for semi-quantitative microbiological evaluation. Tissue samples from the base of the wound together with the adjacent intact tissue of three randomly selected defects of each pig were taken for microbiological, histopathological, and molecular-biological examination. The infection with the inoculated S. aureus strains was sufficient during the whole experiment as confirmed by both FPIT and from tissue samples. The dynamics of the inflammatory markers and clinical signs of infection are also described.

Conclusions: A successfully developed porcine model is suitable for in vivo testing of novel short-acting topical antimicrobial agents.

Background: Over the past few decades, a threefold increase in obesity and type 2 diabetes (T2D) has placed a heavy burden on the health-care system and society. Previous studies have shown correlations between obesity, T2D, and neurodegenerative diseases, including dementia. It is imperative to further understand the relationship between obesity, T2D, and cognitive deficits.

Methods: This investigation tested and evaluated the cognitive impact of obesity and T2D induced by high-fat diet (HFD) and the effect of the host genetic background on the severity of cognitive decline caused by obesity and T2D in collaborative cross (CC) mice. The CC mice are a genetically diverse panel derived from eight inbred strains.

Results: Our findings demonstrated significant variations in the recorded phenotypes across different CC lines compared to the reference mouse line, C57BL/6J. CC037 line exhibited a substantial increase in body weight on HFD, whereas line CC005 exhibited differing responses based on sex. Glucose tolerance tests revealed significant variations, with some lines like CC005 showing a marked increase in area under the curve (AUC) values on HFD. Organ weights, including brain, spleen, liver, and kidney, varied significantly among the lines and sexes in response to HFD. Behavioral tests using the Morris water maze indicated that cognitive performance was differentially affected by diet and genetic background.

Conclusions: Our study establishes a foundation for future quantitative trait loci mapping using CC lines and identifying genes underlying the comorbidity of Alzheimer's disease (AD), caused by obesity and T2D. The genetic components may offer new tools for early prediction and prevention.