Standardization of experimental animals temporal bone sections

Preparation of the temporal bone for light microscopy is an important step in histological studies of the inner ear. Due to the complexity of structures of the inner ear, it is difficult to measure or compare structures of interest without a commonly accepted standardized measure of temporal bone sections. Therefore, standardization of temporal bone sections is very important for histological assessment of sensory hair cells and peripheral ganglion neurons in the cochlear and vestibular systems. The standardized temporal bone sectioning is oriented to a plane parallel to the outer and internal auditory canals. Sections are collected from the epitympanum to the hypotympanum to reveal layers in the order of the crista ampullaris of the superior and lateral semicircular canals, macula utriculi and macula sacculi, superior vestibular ganglion neurons, macula of saccule and inferior vestibular ganglion neurons, cochlear modiolus, endolymphatic duct and endolymphatic sac, and finally the crista ampullaris of the posterior semicircular canal. Moreover, technical details of preparing for temporal bone sectioning including fixation, decalcification, whole temporal bone staining, embedding penetration, and embedding orientation are also discussed.

Diversified Teaching Methods in Nursing:Using Animal Experimentation to Promote Core Professional Competencies in Basic Nursing Training

Objective： The aim of this project was to train highly professional and specialized nursing students from medical colleges to adapt to bedside clinical care by exploring and discussing various methods of injection and IV infusion in animal experimentation to hone the core professional nursing competencies. Methods： Two classes from the 2012 senior graduating nursing class were randomly selected by a computer to conduct the diversified practical teaching methods based on animal experimentation. A hospital environment was simulated by requiring students to perform different types of injections and practical IV infusion techniques. A comprehensive evaluation of the core professional competencies, as well as other integrated competencies, was conducted to determine the effectiveness of the teaching methods. Results： Two-sampled, pairwise u-tests were performed between the scores of the experimental （nursing class 2） and control （nursing class 1） groups. These findings showed that the overall test scores were significantly higher in the experimental group compared to the control group and that the average P-values for the competencies in various categories were 〈0.01, which indicated statistically significant results. Conclusions： Based on the data from this project, diversified teaching methods for basic nursing training founded on animal experimentation can help nursing students perfect their core professional competencies and improve their overall professional standing. The introduction of animal experimentation requires further verification, and an increased acknowledgement of its benefits through the widespread dissemination of this information.

Effects of mesenchymal stem cell on dopaminergic neurons,motor and memory functions in animal models of Parkinson's disease:a systematic review and meta-analysis

Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease itself.Stem cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s disease.Mesenchymal stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of teratogenicity.We performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal model.We searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,2023.The study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control groups.We use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the meta-analysis.Treatment with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational test.Among the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a protective effect on dopaminergic neurons.Subgroup analysis of the amphetamine-induced rotation test showed a significant reduction only in the intracranial-striatum route(SMD[95%CI]=-2.59[-3.25 to-1.94],P=0.0001,I^(2)=74.4%).The memory test showed significant improvement only in the intravenous route(SMD[95%CI]=4.80[1.84 to 7.76],P=0.027,I^(2)=79.6%).Mesenchymal stem cells have been shown to positively impact motor function and memory function and protect dopaminergic neurons in preclinical models of Parkinson’s disease.Further research is required to determine the optimal stem cell types,modifications,transplanted cell numbe rs,and delivery methods for these protocols.

Polar residual network model for assisting evaluation on rat myocardial infarction segment in myocardial contrast echocardiography

Objective To investigate the value of polar residual network(PResNet)model for assisting evaluation on rat myocardial infarction(MI)segment in myocardial contrast echocardiography(MCE).Methods Twenty-five male SD rats were randomly divided into MI group(n=15)and sham operation group(n=10).MI models were established in MI group through ligation of the left anterior descending coronary artery using atraumatic suture,while no intervention was given to those in sham operation group after thoracotomy.MCE images of both basal and papillary muscle levels on the short axis section of left ventricles were acquired after 1 week,which were assessed independently by 2 junior and 2 senior ultrasound physicians.The evaluating efficacy of MI segment,the mean interpretation time and the consistency were compared whether under the assistance of PResNet model or not.Results No significant difference of efficacy of evaluation on MI segment was found for senior physicians with or without assistance of PResNet model(both P>0.05).Under the assistance of PResNet model,the efficacy of junior physicians for diagnosing MI segment was significantly improved compared with that without the assistance of PResNet model(both P<0.01),and was comparable to that of senior physicians.Under the assistance of PResNet model,the mean interpretation time of each physician was significantly shorter than that without assistance(all P<0.001),and the consistency between junior physicians and among junior and senior physicians were both moderate(Kappa=0.692,0.542),which became better under the assistance(Kappa=0.763,0.749).Conclusion PResNet could improve the efficacy of junior physicians for evaluation on rat MI segment in MCE images,shorten interpretation time with different aptitudes,also improve the consistency to some extent.

Establishment of a chronic biliary disease mouse model with cholecystoduodenal anastomosis for intestinal microbiome preservation

BACKGROUND Chronic biliary disease,including cholangitis and cholecystitis,is attributed to ascending infection by intestinal bacteria.Development of a mouse model for bile duct inflammation is imperative for the advancement of novel therapeutic approaches.Current models fail to replicate the harmful bacterial influx to the biliary tract observed in humans and spread of inflammation to the liver.Therefore,we aimed to establish an animal model of biliary disease that faithfully replicates the mechanisms of human diseases.AIM To establish a cholecystoduodenal anastomosis model capable of mimicking the mechanisms of ascending infection and inflammation observed in human biliary diseases.METHODS We established a mouse biliary disease model by directly connecting the gallbladder and duodenum,enabling ascending infection into the biliary tract without traversing the sphincter of Oddi.RESULTS In the cholecystoduodenal anastomosis mouse model,we observed impaired epithelial structure,wall thickening,and macrophage recruitment in the gallbladder.Despite the absence of postoperative antibiotics,we detected no changes in serum proinflammatory cytokine levels,indicating no systemic inflammation.Moreover,patency between the gallbladder and duodenum was confirmed via common bile duct ligation.Injection of patient-derived pathogenic bacteria into bile duct-ligated mice led to ascending infection,which significantly increased proinflammatory cytokine mRNA expression in the liver,duodenum,and ileum.These results indicate that our mouse model exhibited a direct connection between the gallbladder and duodenum,leading to ascending infection and closely mimicking the clinical features of biliary diseases observed in humans.CONCLUSION The cholecystoduodenal anastomosis mouse model is an effective chronic biliary disease model with significant relevance in the development of microbiome-based therapies for the prevention and treatment of biliary disease.

Advances in cytokine-mediated mechanisms for cardiac regeneration and repair post-myocardial infarction:a comprehensive review

Cardiovascular disease(CVD)has become the leading cause of death globally,imposing significant health and economic burdens.Among these,myocardial infarction(MI)is a predominant cause of mortality.Several animal studies have shown that cytokines participate in cardiac regeneration and repair by modulating cellular proliferation,differentiation,and apoptosis post-MI.Here,we explored the crucial role of cytokines in cardiac regeneration and repair processes in experimental animal models,detailing how cytokines modulate cellular mechanisms involved in repairing cardiac tissue post myocardial infarction(MI).Specifically,it highlights the activation of cardiac stem cells and progenitors,the regulation of inflammatory responses to prevent excessive damage,and the involvement in matrix remodeling to ensure functional integrity of the heart.This comprehensive examination underscores the therapeutic potential of enhancing cytokine secretion to mitigate adverse effects and promote recovery following MI,offering insights into possible interventions that could improve patient outcomes in clinical settings.

CT perfusion at early stage of hepatic diffuse disease

AIM: To determine the validity of the non-invasive method of CT perfusion (CTP) in rat model of hepatic diffuse disease. METHODS: Twenty-eight Wistar rats were divided into two groups. Liver diffuse lesions were induced by diethyln-itrosamine in 14 rats of test group. Rats in control group were bred with pure water. From the 1st to 12th wk after the test group was intervened, both groups were studied every week with CTP. CTP parameters of liver parenchyma in different periods and pathologic changes in two groups were compared and analyzed. RESULTS: The process of hepatic diffuse lesions in test groups was classified into three stages or periods according to the pathologic alterations, namely hepatitis, hepatic fibrosis, and cirrhosis. During this period, hepatic artery flow (HAF) of control group declined slightly, mean transit time (MTT), blood flow (BF) and volume (BV) increased, but there were no significant differences between different periods. In test group, HAF tended to increase gradually, MTT prolonged obviously, BV and BF decreased at the same time. The results of statistical analysis revealed that the difference in the HAF ratio of test group to control group was significant. The ratio of BV and BF in test group to control group in stage of hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis was significantly different, but there was no significant difference between hepatitis and hepatic fibrosis. The main pathological changes in stage of hepatitis were swelling of hepatic cells, while sinusoid capillarization and deposition of collagen aggravated gradually in the extravascular Disse's spaces in stage of fibrosis and early stage of cirrhosis. CONCLUSION: The technique could reflect some early changes of hepatic blood perfusion in rat with liver diffuse disease and is valuable for their early diagnosis.

MR DIFFUSION WEIGHTED IMAGING FOR EVALUATION OF RADIOTHERAPEUTIC EFFECTS ON RABBIT VX2 TUMOR MODEL

Objective To investigate the feasibility of magnetic resonance （MR） diffusion weighted imaging （DWI） for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. Methods Sixteen New Zealand white rabbits received a subcutaneous implantation of VX2 tumor cell suspension 0.5 mL （4× 10^7 ceUs/mL） in their right thighs to set up tumor model. And 2 weeks later they were randomly divided into therapy group （Group T, n = 10） and control group （Group C, n = 6）. Group T received radiotherapy at a single dose of 10 Gy. MR imaging （MRI） scan including short TI inversion recovery echo-planar imaging DWI, T1-weighted imaging （T1WI） and T2-weighted imaging （T2WI） sequences were performed 1 day prior to as well as 1 day, 2 days, 3 days and 7 days after radiotherapy. Group C received only MRI scan at the same time points without any treatment. MRI appearance on T2WI, TlWI, and DWI images was compared and tumor volume was calculated. Apparent diffusion coefficient （ADC） values of the tumor were evaluated in all cases. HE staining was used for pathological study. Results Necrosis （n = 8） and hemorrhage （n = 2） were seen gradually on T2WI and T1WI images of Group T after time point of day 2 after irradiation. In Group C, no obvious necrosis was found until day 7. There was no significant difference in tumor volume between the two groups before radiotherapy. After radiotherapy, tumors in Group T showed a gradual growth but not as obvious as Group C. There was a significant difference in tumor volume between the two groups from day 2 on （P 〈 0.05）. ADC value changed dramatically fight from the 1st day after radiotherapy in Group T [（0.99 ± 0.15） ×10^-3 mm^2/s for 1 day before radiotherapy, （1.23 ± 0.08） ×10^-3 , （1.45 ± 0.07） ×10^-3 , （1.63 ± 0.06） ×10^-3 , and （2.02 ± 0.18） ×10^-3 mm^2 for day 1, 2, 3, and 7]; and ADC value had no significant changes after radiotherapy in Group C except day 7 [（1.07±0.08） ×10^-3 mm^2 for 1 day before radiotherapy, （1.03 ± 0.04）×10^-3 , （1.05 ± 0.02）×10^-3 , （1.05 ± 0.05） ×10^-3 , and （0.95 ± 0.07） ×10^-3 mm^2 for day 1, 2, 3, and 7]. There was significant difference in ADC value between the two groups for each time point after radiotherapy （P 〈 0.01）. Pathological study showed that the number of viable tumor cells in Group T decreased 1 day after radiotherapy, and the inflammatory cell infiltration was marked and almost all viable tumor cells disappeared by day 7 after radiotherapy. Conclusions DWI is a new promising technique for monitoring radiotherapy outcomes. ADC value may give a prior clue on physiological changes of radiotherapy before routine MRI could tell.

Structural shift of gut microbiota during chemopreventive effects of epigallocatechin gallate on colorectal carcinogenesis in mice

AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model was established. Fortytwo female FVB/N mice were randomly divided into the following three groups: group 1(10 mice, negative control) was treated with vehicle, group 2(16 mice, positive control) was treated with AOM plus vehicle, and group 3(16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci(ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16 S r RNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16 S r RNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed.RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS(5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85%(33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria(Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics(Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG's effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group(EG) remained relatively stable.CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.

Effect of Fujian tablet on the expression of Nogo-A mRNA in the cervical spinal cord of middle cerebral artery occlusion model rats

Inhibiting the expression of Nogo-A in cervical spinal cord by use of interaction of antigen and antibody can help the remodeling of corticospinal projection of focal cerebral ischemia model rats to facilitate neurological recovery, which provides a new possible mechanism for drugs to promote neurological recovery. However, the effects of drugs on the expression of Nogo-A in cervical spinal cord are still unclear. OBJECTIVE： To observe the effect of Fujian tablet on the expression of Nogo-A mRNA in cervical spinal cords of middle cerebral artery occlusion （MCAO） rats, and to investigate the possible regulatory effect of Fujian tablet on the regenerated microenvironment of spinal conduction bundle. DESIGN： A randomized and controlled trial taking Wistar rats as experimental animals. SETTING： Department of Neurology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine. MATERIALS： This experiment was carried out in the laboratory of Shandong Academy of Medical Science between June 2005 and July 2006. A total of 40 healthy male Wistar rats, aged 12 weeks, weighing 250 - 300 g, were provided by the Experimental Animal Center of Shandong University. Fujian tablets （main components： Heshouwu, Yinyanghuo, etc） were provided by office of Pharmaceutics of Shandong University of traditional Chinese medicine. Nogo-A detection kit was provided by Wuhan Boster Biotechnology Co.,Ltd., and batch number was 040309009. This experiment was approved by Local Animal Ethics Committee. METHODS： Forty male rats were randomly divided into 4 groups, with 10 in each： normal group, sham-operation group, model group and administration group. Rats in the administration group and model group were subjected to MCAO. Rats in the sham-operation group underwent the same craniotomy, and their middle cerebral arteries （MCA） were not occluded. Rats in the normal group were untouched. Rats in administration group were intragastrically administrated with the solution of Fujian tablet at a dose of 9 g/kg and others were given equal dosage of normal saline two days later. The treatments were done once a day and the course totaled 2 weeks. MAIN OUTCOME MEASURES： The expression of Nogo-A mRNA in slices of cervical spinal cords. RESULTS： Forty rats were involved in the final analysis. The expression of Nogo-A mRNA in the cervical spinal cord of rats in the administration group and model group was significantly decreased as compared with that in the normal group （P 〈 0.01 and P 〈 0.05, respectively）. The expression of Nogo-A mRNA in the administration group was also significantly weaker than that in the model group （P 〈 0.05 ） . CONCLUSION： Fujian tablet can inhibit the expression of Nogo-A mRNA in cervical spinal cords of MCAO rats, which facilitates regeneration and remodeling of cervical spinal cords.

Stem cell therapy for Alzheimer's disease

Alzheimer's disease(AD)is a progressive neurodegenerative disease characterized by memory loss and cognitive impairment.It is caused by synaptic failure and excessive accumulation of misfolded proteins.To date,almost all advanced clinical trials on specific AD-related pathways have failed mostly due to a large number of neurons lost in the brain of patients with AD.Also,currently available drug candidates intervene too late.Stem cells have improved characteristics of self-renewal,proliferation,differentiation,and recombination with the advent of stem cell technology and the transformation of these cells into different types of central nervous system neurons and glial cells.Stem cell treatment has been successful in AD animal models.Recent preclinical studies on stem cell therapy for AD have proved to be promising.Cell replacement therapies,such as human embryonic stem cells or induced pluripotent stem cell–derived neural cells,have the potential to treat patients with AD,and human clinical trials are ongoing in this regard.However,many steps still need to be taken before stem cell therapy becomes a clinically feasible treatment for human AD and related diseases.This paper reviews the pathophysiology of AD and the application prospects of related stem cells based on cell type.

Application of biological dural graft made by meninges from porkers

BACKGROUND： Presently, over 40 kinds of dural grafts have been successively used in clinic. Among them, lyophilized human dura mater with good histocompatibility and less complications is applied most widely. But there are a few reports on cases of infected spongiform encephalopathy following application of lyodura. More ideal repair materials deserve to be further investigated. OBJECTIVE： To investigate the efficiency and safety of biological dural graft made by meninges from porkers to repair meningeal injury. DESIGN： A self-control observation. SETTING： Wuhan General Hospital of Guangzhou Military Area Command of Chinese PLA. MATERIALS： Sixteen New Zealand Rabbits, of either gender, weighing from 2 to 3 kg, of clean grade Ⅱ, with the age of 0.5 - 1 year, were involved in this experiment. The involved rabbits were provided by the Animal Experimental Center of the First Military Medical University of Chinese PLA. Biological surgical patch （dural graft） was developed by Guangdong Guanhao Biotechnological Co.,Ltd. It was processed by using meninges from porkers by tissue engineering technology. METHODS： This experiment was carried out in the Experimental Center of the 157 Hospital of Chinese PLA between December 2003 and June 2004. ①The experimental rabbits were anesthetized. Dura mater was exposed from two sides ofpostmedial line of coronal suture. A rectangular dura mater about 8 mm ×8 mm in size was cut off. Then a biological surgical patch （dural graft） was sheared into insert with 8 mm diameter and sutured. The left dura mater was untouched and used as control. Scalp was sutured, and postoperative wound healing and recovery were observed. ②The anesthetized rabbits were sacrificed at postoperative 3, 14, 30 and 90 days, 4 rabbits once. The whole head was cut off, and its scalp was removed. Afterwards, the head was fixed by formalin. Tissues in operative site were obtained, performed routine paraffin embedding, sliced and conducted HE staining, finally, the sections were observed. White blood cells in venous blood were counted before operation and execution, separately. The obtained data were statistically analyzed. MAIN OUTCOME MEASURES： ①Wound healing and recovery following implantation of dural graft. ②The amount of white blood cells in venous blood from rabbits at each time point before operation and before execution. ③Histological examination results of operative site. RESULTS： Sixteen experimental rabbits were involved in the final analysis. ①The experimental rabbits of each group had no local infection, effusion and abnormal appearance. They had good wound healing and were normal to access to food. ②There were no significant differences in amount of white blood cells in venous blood from experimental rabbits between at each time point after modeling and before operation （P 〉 0.05）. ③Pathological observation of operative site ： At postoperative 3 days, local acute inflammation repair reaction appeared; At postoperative 2 weeks, chronic inflammatory reaction appeared, endodermis in artificial dural graft formed, and artificial dural graft and host dura mater healed; In postoperative 1 month, wound began to chronically recover; In postoperative 3 months, host blood capillary began to form in artificial dural graft based on chronic repair. In all the control sides, fibroplasia was found, and a few neutrophils were found at postoperative 2 weeks. CONCLUSION： Biological surgical patch has high stability and good histocompatibility. It can provide dural epithelial epithelium, effectively prevent against the conglutination of scalp tissue and brain tissue, and avoid the leakage ofcerebrospinal fluid.

Neural stem cell therapy for brain disease

Brain diseases, including brain tumors, neurodegenerative disorders, cerebrovasculardiseases, and traumatic brain injuries, are among the major disordersinfluencing human health, currently with no effective therapy. Due to the lowregeneration capacity of neurons, insufficient secretion of neurotrophic factors,and the aggravation of ischemia and hypoxia after nerve injury, irreversible lossof functional neurons and nerve tissue damage occurs. This damage is difficult torepair and regenerate the central nervous system after injury. Neural stem cells(NSCs) are pluripotent stem cells that only exist in the central nervous system.They have good self-renewal potential and ability to differentiate into neurons,astrocytes, and oligodendrocytes and improve the cellular microenvironment.NSC transplantation approaches have been made for various neurodegenerativedisorders based on their regenerative potential. This review summarizes anddiscusses the characteristics of NSCs, and the advantages and effects of NSCs inthe treatment of brain diseases and limitations of NSC transplantation that need tobe addressed for the treatment of brain diseases in the future.

Is it necessary to use the entire root as a donor when transferring contralateral C7 nerve to repair median nerve？

If a partial contralateral C7 nerve is transferred to a recipient injured nerve, results are not satisfactory. However, if an entire contralateral C7 nerve is used to repair two nerves, both recipient nerves show good recovery. These findings seem contradictory, as the above two methods use the same donor nerve, only the cutting method of the contralateral C7 nerve is different. To verify whether this can actually result in different repair effects, we divided rats with right total brachial plexus injury into three groups. In the entire root group, the entire contralateral C7 root was transected and transferred to the median nerve of the affected limb. In the posterior division group, only the posterior division of the contralateral C7 root was transected and transferred to the median nerve. In the entire root ＋ posterior division group, the entire contralateral C7 root was transected but only the posterior division was transferred to the median nerve. After neurectomy,the median nerve was repaired on the affected side in the three groups. At 8, 12, and 16 weeks postoperatively, electrophysiological examination showed that maximum amplitude, latency, muscle tetanic contraction force, and muscle fiber cross-sectional area of the flexor digitorum superficialis muscle were significantly better in the entire root and entire root ＋ posterior division groups than in the posterior division group. No significant difference was found between the entire root and entire root ＋ posterior division groups. Counts of myelinated axons in the median nerve were greater in the entire root group than in the entire root ＋ posterior division group, which were greater than the posterior division group. We conclude that for the same recipient nerve, harvesting of the entire contralateral C7 root achieved significantly better recovery than partial harvesting, even if only part of the entire root was used for transfer. This result indicates that the entire root should be used as a donor when transferring contralateral C7 nerve.

Biocompatibility of vascular stents manufactured using metal injection molding in animal experiments

This study aimed to evaluate the feasibility and safety of a novel stent manufactured by metal injection molding(MIM)in clinical practice through animal experiments.Vessel stents were prepared using powder injection molding technology to considerably improve material utilization.The influence of MIM carbon impurity variation on the mechanical properties and corrosion resistance of 316L stainless steel was studied.In vitro cytotoxicity and animal transplantation tests were also carried out to evaluate the safety of MIM stents.The results showed that the performance of 316L stainless steel was very sensitive to the carbon content.Carbon fluctuations should be precisely controlled during MIM.All MIM stents were successfully implanted into the aortas of the dogs,and the MIM 316L stents had no significant cytotoxicity.The novel intravascular stent manufactured using MIM can maintain a stable form and structure with fast endothelialization of the luminal surface of the stent and ensure long-term patency in an animal model.The novel intravascular stent manufactured using MIM demonstrates favorable structural,physical,and chemical stability,as well as biocompatibility,offering promising application in clinical practice.

Advances in viral encephalitis:Viral transmission,host immunity,and experimental animal models

Viral infections have led to many public health crises and pandemics in the last few centuries.Neurotropic virus infection-induced viral encephalitis(VE),especially the symptomatic inflammation of the meninges and brain parenchyma,has attracted growing attention due to its high mortality and disability rates.Understanding the infectious routes of neurotropic viruses and the mechanism underlying the host immune response is critical to reduce viral spread and improve antiviral therapy outcomes.In this review,we summarize the common categories of neurotropic viruses,viral transmission routes in the body,host immune responses,and experimental animal models used for VE study to gain a deeper understanding of recent progress in the pathogenic and immunological mechanisms under neurotropic viral infection.This review should provide valuable resources and perspectives on how to cope with pandemic infections.

Stem cells:a promising candidate to treat neurological disorders

Neurologic impairments are usually irreversible as a result of limited regeneration in the central nervous system.Therefore,based on the regenerative capacity of stem cells,transplantation therapies of various stem cells have been tested in basic research and preclinical trials,and some have shown great prospects.This manuscript overviews the cellular and molecular characteristics of embryonic stem cells,induced pluripotent stem cells,neural stem cells,retinal stem/progenitor cells,mesenchymal stem/stromal cells,and their derivatives in vivo and in vitro as sources for regenerative therapy.These cells have all been considered as candidates to treat several major neurological disorders and diseases,owing to their self-renewal capacity,multi-directional differentiation,neurotrophic properties,and immune modulation effects.We also review representative basic research and recent clinical trials using stem cells for neurodegenerative diseases,including Parkinson＇s disease,Alzheimer＇s disease,and age-related macular degeneration,as well as traumatic brain injury and glioblastoma.In spite of a few unsuccessful cases,risks of tumorigenicity,and ethical concerns,most results of animal experiments and clinical trials demonstrate efficacious therapeutic effects of stem cells in the treatment of nervous system disease.In summary,these emerging findings in regenerative medicine are likely to contribute to breakthroughs in the treatment of neurological disorders.Thus,stem cells are a promising candidate for the treatment of nervous system diseases.

Separation and Anti-Hantaan Virus Activity of Extracts from Alternanthera philoxcroides in vitro and in vivo

A water-soluble substance was extracted from the Chinese herb, Alternantheraphiloxcroides with hot water and alcohol. Aliquots of this initial extract were further fractionated by treatment with ether, ethyl acetate and alcohol respectively. The four extracts were assayed for anti-viral activity against three serum, Hantaan virus 114 （HV114）, HV435 and A9 strains. Results show that the four extracts are capable of inhibiting Hantaan virus propagation, of which extract No. 1 has the best efficiency. The three dosage of extract No. 1, which are used upon three Hantaan virus serum IC50, are 153, 157, 154 μg/mL. New-born mice were made to be infected with HV114 and then fed in vivo with extract No.l on the 3rd, 10th and 14th days after being infected by the virus. The treatment continued for 8 days with a dosage of 2.5 g/kg. Result shows that survival rates of mice were 75%, 50% and 0, respectively. The median time to death （MTDs） of the three groups were 37, 30, 23 days.

Evaluation of the toxicity of fluorine in Antarctic krill on soft tissues of Wistar rats

Antarctic krill are a potential food source for humans and animals, but krill are known to contain high levels of fluorine （F）. In this study, we investigated the toxicity of F in Antarctic krill using Wistar rats. There were three experimental groups： The control group were fed a basal diet, the krill treatment group were fed the same basal diet mixed with krill powder （150 mg＇kg-~ F）, and the sodium fluoride （NaF） treatment group were fed the basal diet with added NaF （150 mg.kg1 F）. General toxicity indicators including body weight and food intake were measured during the experiment. After three months the rats were dissected and tissue samples were collected from the liver, kidney, spleen, brain, and testis. Morphological changes in the cells of these tissues were assessed using HE staining. There were no significant differences in the body weight, the food intake, or the viscera coefficients among the three groups. In both treatment groups some pathological changes were observed in all soft tissue samples except the testis, although there were fewer and less severe pathological changes in the krill treatment group than in the NaF treatment group. The results showed that the toxicity of F in Antarctic krill was lower than for an equivalent amount of F in NaF, but it was still toxic to rats consuming large quantities of krill. The findings of this study highlight the need for further investigation into potential F toxicity if krill is to be used for human consumption.

Animal modeling in bone research—Should we follow the White Rabbit?

Animal models are live subjects applied to translational research.They provide insights into human diseases and enhance biomedical knowledge.Livestock development has favored the pace of human social development over millennia.Today's society is more aware of animal welfare than past generations.The general public has marked objections to animal research and many species are falling into disuse.The search for an ideal methodology to replace animal use is on,but animal modeling still holds great importance to human health.Bone research,in particular,has unmet requirements that in vitro technologies cannot fully address.Standardizing novel models remains necessary and rabbits are gaining in popularity as potential bone models.Our aim here is to provide a broad overview of animal modeling and its ethical implications,followed by a narrower focus on bone research and the role rabbits are playing in the current scenario.