Weightlessness in the space environment affects astronauts' learning memory and cognitive function. Repetitive transcranial magnetic stimulation has been shown to be effective in improving cognitive dysfunction. In this study, we investigated the effects of repetitive transcranial magnetic stimulation on neural excitability and ion channels in simulated weightlessness mice from a neurophysiological perspective. Young C57 mice were divided into control, hindlimb unloading and magnetic stimulation groups. The mice in the hindlimb unloading and magnetic stimulation groups were treated with hindlimb unloading for 14 days to establish a simulated weightlessness model, while the mice in the magnetic stimulation group were subjected to 14 days of repetitive transcranial magnetic stimulation. Using isolated brain slice patch clamp experiments, the relevant indexes of action potential and the kinetic property changes of voltage-gated sodium and potassium channels were detected to analyze the excitability of neurons and their ion channel mechanisms. The results showed that the behavioral cognitive ability and neuronal excitability of the mice decreased significantly with hindlimb unloading. Repetitive transcranial magnetic stimulation could significantly improve the cognitive impairment and neuroelectrophysiological indexes of the hindlimb unloading mice. Repetitive transcranial magnetic stimulation may change the activation, inactivation and reactivation process of sodium and potassium ion channels by promoting sodium ion outflow and inhibiting potassium ion, and affect the dynamic characteristics of ion channels, so as to enhance the excitability of single neurons and improve the cognitive damage and spatial memory ability of hindlimb unloading mice.
Animals ; Mice ; Transcranial Magnetic Stimulation ; Hindlimb Suspension ; Neurons ; Cognitive Dysfunction ; Brain

Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.
Animals ; Hindlimb/metabolism* ; Mitochondria/metabolism* ; Mitochondrial Dynamics ; Mitochondrial Proteins/pharmacology* ; Muscle, Skeletal ; Rabbits ; Vibration/adverse effects*

Animals ; Hindlimb ; Male ; Mice ; Mice, Inbred C57BL ; Muscle Fibers, Skeletal ; Muscle, Skeletal/pathology* ; Muscular Atrophy

hindlimb lameness associated with generalised soft tissue swelling of the entire limb and medial saphenous vein (MSV) thrombophlebitis. A presumptive diagnosis of extremity compartment syndrome (ECS) was made. Due to the clinical deterioration, emergency fasciotomy of the crural fascia and biopsy was performed. Histological and immunohistochemical examination of the samples confirmed a diagnosis of leiomyosarcoma likely originating from the tunica media of the MSV. This report is the first to describe an unique combination of ECS and thrombophlebitis associated with a leiomyosarcoma in a horse.]]>
Animals ; Biopsy ; Child ; Compartment Syndromes ; Diagnosis ; Emergencies ; Extremities ; Fascia ; Hindlimb ; Horses ; Humans ; Leiomyosarcoma ; Saphenous Vein ; Thrombophlebitis ; Tunica Media

OBJECTIVE: Sequelae of behavioral impairments associated with human traumatic brain injury (TBI) include neurobehavioral problems. We compared exploratory, cognitive, and depressive-like behaviors in pediatric and adult male mice exposed to controlled cortical impact (CCI).METHODS: Pediatric (21 to 25 days old) and adult (8 to 12 weeks old) male C57Bl/6 mice underwent CCI at a 2-mm depth of deflection. Hematoxylin and eosin staining was performed 3 to 7 days after recovery from CCI, and injury volume was analyzed using ImageJ. Neurobehavioral characterization after CCI was performed using the Barnes maze test (BMT), passive avoidance test, open-field test, light/dark test, tail suspension test, and rotarod test. Acutely and subacutely (3 and 7 days after CCI, respectively), CCI mice showed graded injury compared to sham mice for all analyzed deflection depths.RESULTS: Time-dependent differences in injury volume were noted between 3 and 7 days following 2-mm TBI in adult mice. In the BMT, 2-mm TBI adults showed spatial memory deficits compared to sham adults (P < 0.05). However, no difference in spatial learning and memory was found between sham and 2-mm CCI groups among pediatric mice. The open-field test, light/dark test, and tail suspension test did not reveal differences in anxiety-like behaviors in both age groups.CONCLUSION: Our findings revealed a graded injury response in both age groups. The BMT was an efficient cognitive test for assessing spatial/non-spatial learning following CCI in adult mice; however, spatial learning impairments in pediatric mice could not be assessed.
Adult ; Animals ; Brain Injuries ; Eosine Yellowish-(YS) ; Hematoxylin ; Hindlimb Suspension ; Humans ; Learning ; Male ; Memory ; Mice ; Rotarod Performance Test ; Spatial Learning ; Spatial Memory

OBJECTIVE: To introduce a modified protocol for generating the simulated weightlessness rat model by hindlimb unloading. METHODS: Ninety male adult SD rats were randomly divided into three groups: the control group, classical suspension group and modified suspension group (n=30/group). In the classical suspension group, a strip of medical adhesive tape was attached to the tail, with horizontal filament tape wrapping. A piece of gauze was wrapped around the tail at the outermost layer and the tail was suspended for hindlimb unloading. In the modified suspension group, a layer of plastic net was added between the horizontal filament tape and the gauze to reduce the squeeze on the tail as a buffer zone and ensure proper circulation of the tail. After 4 weeks of suspension, damage to the tail and sheath detachment were observed. Meanwhile the body weight and right soleus wet weight of rats were measured. RESULTS: The ratio of right soleus wet weight to body weight was decreased significantly in both the classical suspension group and the modified suspension group compared with the control group, while there was no difference in body weight among the three different groups. Importantly, the incidence of tail ischemia and necrosis (13.3% vs 40.0% in the classical suspension group) and the incidence of sheath detachment from tail (3.3% vs 26.7% in the classical suspension group) were significantly lower whereas the success rates of model (33.3% vs 83.3% in classical suspension group) was significantly higher in the modified suspension group. CONCLUSION The modified protocol decreases the incidence of tail necrosis and sheath detachment in the rat tail suspension and increases the success rate of the hindlimb unloading rat model, with improved simplicity and practicability.
Animals ; Hindlimb Suspension ; Male ; Muscle, Skeletal ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Weightlessness Simulation ; methods

PURPOSE: Sentinel lymph node biopsy (SLNB), a critical staging and treatment step, has replaced axillary lymph node (LN) dissection as the standard staging procedure for early stage breast cancer patients with clinically negative axillary LNs. Hence, using a murine sentinel lymph node (SLN) model, we investigated the localization effect of the new receptor-targeted tracer, indocyanine green (ICG)-rituximab, on breast cancer SLNB. METHODS: After establishing the murine SLN model, different doses of ICG-rituximab were subcutaneously injected into the hind insteps of BALB/c mice to determine the optimal dose and imaging time using continuous (> 3 hours) MDM-I fluorescence vasculature imaging. To explore the capacity of ICG-rituximab for sustained SLN localization with the optimal dose, MDM-I imaging was monitored at 6, 12, and 24 hours. RESULTS: The popliteal LN was defined as the SLN for hindlimb lymphatic drainage, the iliac LN as the secondary, and the para-aortic or renal LN as the tertiary LNs. The SLN initial imaging and optimal imaging times were shortened with increased ICG-rituximab doses, and the imaging rates of the secondary and tertiary LNs increased accordingly. The optimal ICG dose was 0.12 μg, and its optimal imaging time was 34 minutes. After 24 hours, the SLN imaging rate remained 100%, while those of the secondary and the tertiary LNs increased from 0% (6 hours) and 0% (6 hours) to 10% (12 hours) and 10% (12 hours) to 20% (24 hours) and 10% (24 hours), respectively. CONCLUSION: ICG-rituximab localized to the SLN without imaging from the secondary or tertiary LNs within 6 hours. The optimal ICG dose was 0.12 μg, and the optimal interval for SLN detection was 34 minutes to 6 hours post-injection. This novel receptor-targeted tracer is of great value to clinical research and application.
Animals ; Breast Neoplasms ; Breast ; Drainage ; Fluorescence ; Hindlimb ; Humans ; Indocyanine Green ; Lymph Nodes ; Mice ; Models, Animal ; Rituximab ; Sentinel Lymph Node Biopsy

OBJECTIVE: To better understand the pathological causes of bone loss in a space environment, including microgravity, ionizing radiation, and ultradian rhythms. METHODS: Sprague Dawley (SD) rats were randomly divided into a baseline group, a control group, a hindlimb suspension group, a radiation group, a ultradian rhythms group and a combined-three-factor group. After four weeks of hindlimb suspension followed by X-ray exposure and/or ultradian rhythms, biomechanical properties, bone mineral density, histological analysis, microstructure parameters, and bone turnover markers were detected to evaluate bone loss in hindlimbs of rats. RESULTS: Simulated microgravity or combined-three factors treatment led to a significant decrease in the biomechanical properties of bones, reduction in bone mineral density, and deterioration of trabecular parameters. Ionizing radiation exposure also showed adverse impact while ultradian rhythms had no significant effect on these outcomes. Decrease in the concentration of the turnover markers bone alkaline phosphatase (bALP), osteocalcin (OCN), and tartrate-resistant acid phosphatase-5b (TRAP-5b) in serum was in line with the changes in trabecular parameters. CONCLUSION Simulated microgravity is the main contributor of bone loss. Radiation also results in deleterious effects but ultradian rhythms has no significant effect. Combined-three factors treatment do not exacerbate bone loss when compared to simulated microgravity treatment alone.
Animals ; Biomechanical Phenomena ; Bone Density ; physiology ; Bone Resorption ; etiology ; metabolism ; Femur ; metabolism ; Hindlimb Suspension ; Rats, Sprague-Dawley ; Tibia ; metabolism ; Ultradian Rhythm ; Weightlessness Simulation ; adverse effects ; X-Rays ; adverse effects

To investigate the behavioral and biomolecular similarity between neuralgia and depression, a trigeminal neuralgia (TN) mouse model was established by constriction of the infraorbital nerve (CION) to mimic clinical trigeminal neuropathic pain. A mouse learned helplessness (LH) model was developed to investigate inescapable foot-shock-induced psychiatric disorders like depression in humans. Mass spectrometry was used to assess changes in the biomolecules and signaling pathways in the hippocampus from TN or LH mice. TN mice developed not only significant mechanical allodynia but also depressive-like behaviors (mainly behavioral despair) at 2 weeks after CION, similar to LH mice. MS analysis demonstrated common and distinctive protein changes in the hippocampus between groups. Many protein function families (such as cell-to-cell signaling and interaction, and cell assembly and organization,) and signaling pathways (e.g., the Huntington's disease pathway) were involved in chronic neuralgia and depression. Together, these results demonstrated that the LH and TN models both develop depressive-like behaviors, and revealed the involvement of many psychiatric disorder-related biomolecules/pathways in the pathogenesis of TN and LH.
Animals ; Avoidance Learning ; physiology ; Brain-Derived Neurotrophic Factor ; metabolism ; Depression ; etiology ; pathology ; Disease Models, Animal ; Electroshock ; adverse effects ; Functional Laterality ; Helplessness, Learned ; Hindlimb Suspension ; psychology ; Hippocampus ; metabolism ; Male ; Mass Spectrometry ; Mice ; Mice, Inbred C57BL ; Orbit ; innervation ; Pain Measurement ; Proteomics ; methods ; Reaction Time ; physiology ; Signal Transduction ; physiology ; Trigeminal Neuralgia ; etiology ; pathology

A recent study reveals that missense mutations of EWSR1 are associated with neurodegenerative disorders such as amyotrophic lateral sclerosis, but the function of wild-type (WT) EWSR1 in the central nervous system (CNS) is not known yet. Herein, we investigated the neuroanatomical and motor function changes in Ewsr1 knock out (KO) mice. First, we quantified neuronal nucleus size in the motor cortex, dorsal striatum and hippocampus of three different groups: WT, heterozygous Ewsr1 KO (+/−), and homozygous Ewsr1 KO (−/−) mice. The neuronal nucleus size was significantly smaller in the motor cortex and striatum of homozygous Ewsr1 KO (−/−) mice than that of WT. In addition, in the hippocampus, the neuronal nucleus size was significantly smaller in both heterozygous Ewsr1 KO (+/−) and homozygous Ewsr1 KO (−/−) mice. We then assessed motor function of Ewsr1 KO (−/−) and WT mice by a tail suspension test. Both forelimb and hindlimb movements were significantly increased in Ewsr1 KO (−/−) mice. Lastly, we performed immunohistochemistry to examine the expression of TH, DARPP-32, and phosphorylated (p)-DARPP-32 (Thr75) in the striatum and substantia nigra, which are associated with dopaminergic signaling. The immunoreactivity of TH and DARPP-32 was decreased in Ewsr1 KO (−/−) mice. Together, our results suggest that EWSR1 plays a significant role in neuronal morphology, dopaminergic signaling pathways, and motor function in the CNS of mice.
Amyotrophic Lateral Sclerosis ; Animals ; Central Nervous System ; Dopamine ; Forelimb ; Hindlimb ; Hindlimb Suspension ; Hippocampus ; Immunohistochemistry ; Mice* ; Motor Cortex ; Mutation, Missense ; Neurodegenerative Diseases ; Neurons ; RNA* ; RNA-Binding Proteins* ; Substantia Nigra