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.

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.

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.

Exploration of the Characteristics of Animal Supply and Demand in University Experimental Teaching Pratice

The supply and demand of laboratory animals for teaching in colleges and universities has its own internal characteristics.To grasp the supply and demand characteristics of laboratory animals for teaching is of vital importance to the planning,supply and use of teaching animals,the realization of teaching objectives and the completion of teaching tasks.Based on the supply of teaching experimental animals and the work of animal experimental teaching in our university in recent years,this paper expounds the inherent characteristics and practice of supply and demand of teaching experimental animals.

Experimental Studies on immune－Complex in Situ Type Glomerulonephritis in Rabbits Treated with Mai－Luo－Tong and Natural Indig

By injection of C-BSA. immune-complex in situ type glomerulonephritis was duplicated in rabbits and treated with Mai-Luo-Tong and natural Indigo.The resuts showed that proteinuria in the treated groups M and Q was decreased.The difference between group M and control group is statistically significant (P<0.05). Under light and electron microscope.although glomerular basement membrane was irregularly thickened and subepithelial dense electron deposited in the treated group, but microthromhus. erythrocytes and platelets aggregation and leukocytes impaction were not seen within glomerular capillaries. Also in groups C,Q,M, mesenteric cell count was 99. 40±18.53,92.87±17. 89,66. 55±7.75 respectively,the M.Q groups are compared with group C, the result is of statistical significance(P<0.05)and there is no apparent glomerular fibrosis in the treated groups.

Alteration of Nitric Oxide Synthase in Experimental Spinal Cord Injury in Rats

In order to detect the role of NO to the secondary damage following spinal cord injury (SCI). NOS in the injury site (T\-8) were studied using a rat SCI model induced by Allens weight drop method (10 g2.5 cm). The results suggested that activities of NOS significantly increased in 10 min\, 1\,2\,4\,8 h. The results indicated that NO was related to SCI. The rise of NO following SCI might lead to secondary spinal cord damage.\;

An Experimental Study on Somatostatin Receptors in the Brains of Hepatic Encephaiopathy Rats

The present study was undertaken to evaluate the effect of somatostatin (SS) receptor,a brain-gut peptide receptor which is capable of inhibiting central neurons, on the pathogenesis of hepatic encephalopathy (HE).By means of radioligand binding assay, SS receptors in crude synaptosomal membrane of rat brains were investigated in a rat model of HE induced by partial hepatectomy following carbon tetrachloride intoxication and in controls. Binding to SS receptor was studied using125 I-SS as radiolgand Scatchard analysis of binding data was linear, yielding a dissociation constant (Kd) of 3.99 ±0.22 nmol/L and a maximal binding capacity (Bmax) of 238± 14.2 fmol/mg of protein in HE rats.Only increased Bmax values were observed (P< 0.005),while the Kd values were statistically unchanged (P>0.50),in HE rats as compared with those in controls.The results suggest that the changes of SS receptors in brains play a significant role in the pathogenesis of HE.The mechanism of HE induced by the alterations of SS receptors in the brains was discussed in this paper.

A New Model of Experimental Cerebral Infarction in New Zealand White Rabbits

To develop an easy, reproducible experimental model of cerebral infarction(CI)without craniotomy in New Zealand white rabbits,a silicone rubber cylinder embedded in a nylon suture was delivered to the middle cerebral arteries through the internal carotid artery in anesthetized animals.Rabbits were sacrificed 0.5-5 h after embolization.CI size and location were ascertained by the tripheny1-2H-tetrazoliuni chloride(TTC)staining method;cerebral blood flow(CBF)was measured prior to and after embolization.Pco2,temperature and blood pressure were monitored and kept constant.CI occurred in all rabbits after 4 h of ischemia,in 50% after 3 h and only in 33% after 2.5 h.CI did not occur within less than 2.5 h of ischemia.No correlation was found between size and location of CI and occlusion time.CBF was maximally reduced in the right MCA territory but was also reduced in both anterior cerebral arteries and left MCA territories.This model is technically easy and the retrievable embolus allows the study of reperfusion by pulling on the nylon suture.It is suitable for studying chemical and molecular changes of the ischemic cells and/or for studying neuroimage changes after ischemic stroke.

Complete Achilles Tenotomy:A New Improved Experimental Surgical Technique in Rats

Rupture of the Achilles tendon is one of the most frequent tendon injuries in humans. However, there is no standard surgical technique thus far to reproduce complete rupture of this tendon in rats. Surgical procedures were performed in Wistar rats under light microscopy, with posterior longitudinal incision and preservation of the plantaris tendon. The animals were sacrificed on 2nd and 8th postoperative week and we used hematoxilin and eosin, picrosirius-red and Weigert’s resorcin-fuchsin to observe general tendon healing. The mean operative time was one minute and 24 seconds. Histological studies showed cellular proliferation and fibrillogenesis at two weeks, with decreased amounts of cellularity and elastic fibers at the 8th week, besides changes in structural organization of collagen fibers. The complete Achilles tenotomy in rats, was improved under light microscopy and sparing the plantaris tendon. This surgical technique was simple and quick, showed signs of normal healing process, could be easily reproducible, and triggered translational researches in this area.

Experimental study of tibial transverse bone transfer on wound healing of diabetic rabbit leg ulcer

Objective To investigate the efficacy and mechanism of tibial transverse bone transfer in the treatment of lower limb ulcer wounds in diabetic rabbits.Methods Animal models of diabetic foot lower extremity ischemia were made,and grouped Animal models of diabetic foot lower extremity ischemia were made,and grouped control studies were designed to evaluate the time of wound healing and the expression level of vascular endothelial growth factor(VEGF),platelet derived growth factor(PDGF),and epidermal cell growth factor(EGF)in the wound during the same period of time.Results In animal experiments,transverse tibial bone transfer can shorten the healing time of diabetic ulcer and increase the expression of wound growth factor(VEGF,PDGF,EGF).Conclusion In animal experiments,diabetes can inhibit the expression of growth factors(VEGF,PDGF,EGF)in ulcer wounds,and tibial transverse bone transfer can promote wound healing.The mechanism may be related to the increased expression of VEGF,PDGF and EGF in the wound surface.

Fundus photography,fundus fluorescein angiography,and optical coherence tomography of healthy cynomolgus monkey,New Zealand rabbit,Sprague Dawley rat,and BALB/c mouse retinas

Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measurability of specific parameters or structures,the applicability of clinical measurement technologies,and the similarity to human eye function.Studies of eye pathology usually compare optical parameters between a healthy and altered state,so accurate baseline assessments are critical,but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.Methods:Three cynomolgus monkeys,six New Zealand rabbits,ten Sprague Dawley(SD)rats,and BALB/c mice were examined by fundus photography(FP),fundus fluorescein angiography(FFA),and optical coherence tomography(OCT).Results:Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP,FFA,and OCT.New Zealand rabbits have large eyeballs,but they have large optic disc and myelinated retinal nerve fibers in their retinas,and the growth pattern of retinal vessels were also different to the human retinas.Unlike monkeys and rabbits,the retinal vessels of SD rats and BALB/c mice were widely distributed and clear.The OCT performance of them were similar with human beings except the macular.Conclusions:Monkey is a good model to study changes in retinal structure associated with fundus disease,rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases,and rats and mice are good models for retinal vascular diseases.These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

Study on prescription medication mode and mechanism of traditional Chinese medicine in the treatment of noncritical COVID-19 based on data mining

Background:As of 2023,coronavirus disease 2019(COVID-19)is still spreading globally.Therefore,we aim to integrate non-critical COVID-19 high-frequency and high-targeting Chinese medicines to provide a reference for clinical prescriptions to improve COVID-19-related symptoms.Materials and methods:The information on non-critical COVID-19 high-frequency Chinese medicines in the diagnosis and treatment of COVID-19 was obtained by the TCM inheritance support platform.Using network pharmacology and molecular docking technology,high-targeting Chinese medicines with good docking activity with COVID-19 receptors angiotensin-converting enzyme-II(ACE2),3CLpro and tyrosine-protein kinase receptor UFO(AXL)were obtained.A new prescription for non-critical COVID-19 was established by integrating high-frequency and high-targeting Chinese medicines.Rats with acute lung injury induced by lipopolysaccharide were used as the experimental model.The histopathological changes in the lungs of rats in each group were observed by hematoxylin-eosin staining.The lung coefficient of rats was measured.The levels of IL-6,TNF-α,and IL-1βin serum were detected by enzyme-linked immunosorbent assay.The mRNA and protein levels of ACE2 and AXL in lung tissue were detected by real-time quantitative polymerase chain reaction and western blot.Results:Through data mining,it was found that there were 39 high-frequency traditional Chinese medicines for non-critical COVID-19 in the diagnosis and treatment guidelines.According to network pharmacology and molecular docking,30 highly targeted traditional Chinese drugs for COVID-19 were found.The new prescriptions for non-critical COVID-19 were comprehensively obtained,including Glycyrrhizae Radix,Ephedra Herba,Amygdalus Communis Vas,Gypsum Fibrosum,Descurainiae Semen,Atractylodes Lancea,Scutellariae Radix,Amomum Tsao-Ko Crevostet,Forsythiae Fructus,Pogostemon cablin,Magnolia Officinalis.Compared with the LPS-induced lung injury model group,the medium dose of the new prescription group had significantly alleviated pathological changes in lung tissue,decreased lung coefficient,decreased contents of IL-6,TNF-αand IL-1β,and increased mRNA and protein expression of ACE2 and AXL(P<0.05).Conclusion:Based on data mining,network pharmacology and molecular docking technology,the new prescription for non-critical COVID-19 established by this method has an anti-inflammatory effect on rats with acute lung injury induced by lipopolysaccharide and can provide a reference for clinicians to alleviate the symptoms related to non-critical COVID-19.

Regulation of Quan Du Zhong capsule on VEGF/bFGF and expression of Bcl‑2/Bax and Caspase‑3 protein in the repairing process of canine femoral head necrosis

Objective:To explore the repair and treatment effect of Quan Du Zhong capsule on necrosis of femoral head in dogs.Methods:Totally 12 beagles were randomly divided into normal group,model group,Quan Du Zhong capsule group and Xianlinggubao capsule group,with three in each group.In addition to the normal group,the other groups established the femoral head necrosis model by liquid nitrogen alternative freezing.The normal group and the model group did not have any intervention during the modeling period,and the Quan Du Zhong group began to receive the Quan Du Zhong by gavage on the day of modeling;Xianlinggubao capsule group was given Xianlinggubao capsule by gavage once a day for 12 consecutive weeks on the day of modeling.The levels of VEGF and bFGF in the blood vessels of each group at the 12th week were compared,and the ratios of BMD,BS/BV,BV/TV,Tb.Th,Tb.N were measured by Micro CT,and the expressions of Bcl-2,Bax,Caspase-3 proteins were detected by immune reaction.Results:1.Compared with the normal group,the level of serum VEGF and bFGF in the model group decreased after 12 weeks of modeling(P<0.05);Compared with the model group,the levels of serum VEGF and bFGF water in the Xianlinggubao capsule group and the Quan Du Zhong capsule group increased on average at the 12th week of modeling,with statistical difference(P<0.05).The level of the Quan Du Zhong capsule group was the highest,followed by the Xianlinggubao capsule group.2.Compared with the normal group,BMD,BS/BV,BV/TV,Tb.Th and Tb.N in the model group were lower,and Tb.SP were higher,the results were statistically significant(P<0.05).Compared with the model group,the BMD,BV/TV,Tb.Th and Tb.N of Xianlinggubao capsule group and the total eucommia capsule group increased,while the BS/BV and Tb.SP decreased(P<0.05).3.The Quan Du Zhong capsule group and Xianlinggubao capsule group could significantly increase the expression of bcl-2 protein in the femoral head of dogs,which was significantly different from the model group(P<0.05).The expression of bax protein in the femoral head of dogs in the Quan Du Zhong capsule group and the Xianlinggubao capsule group was significantly reduced compared with the model group(P<0.05).The expression of caspase-3 protein in the femoral head of dogs was significantly reduced in the Quan Du Zhong capsule group and Xianlinggubao capsule group,which was significantly different from the model group(P<0.05).Conclusion:Quan Du Zhong capsule can increase the expression of VEGF and bFGF in serum,increase the expression of bcl-2,inhibit the expression of bax,and reduce the expression of caspase-3,which plays a synergistic role in the treatment of avascular necrosis of the femoral head,and has potential targets.

High Linoleic Acid in the Food Supply Worldwide-What are the Consequences?

The macronutrient composition of food supply in China has altered dramatically in the past 70 years.Fat(oil)has increased more than 4.2-times while the carbohydrate content has declined by 34%.Vegetable oils are the major component of the fat intake and since these oils are rich in linoleic acid,there has been a significant rise in the consumption of this fatty acid(as much as a 4-fold rise).Linoleic acid has essential functions in the body in skin and as a precursor of prostaglandins and related compounds.The current intakes of linoleic acid are well in excess of the minimum requirements.In this review,the effects of a food supply rich in linoleic acid on pain in arthritis and headache,non-alcoholic fatty liver and neural function are explored,with emphasis on lipid mediators derived from linoleic acid and other long chain polyunsaturated fatty acids.The current world food systems have created an imbalance of dietary linoleic acid in relation to n-3 polyunsaturated fatty acids,and an imbalance in the lipid mediators derived from these polyunsaturated fatty acids which may be contributing to sub-optimal health status.

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.

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.

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.

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.

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.