A neglected normal anatomical structure in mammal: a study in bats and tree shrews / Una estructura anatómica normal desatendida en mamíferos: un estudio en murciélagos y musarañas arborícolas

SUMMARY: The myodural bridge is a dense connective tissue connecting muscles and ligaments to the spinal dura mater in the atlanto-occipital interspace. Some researchers believe that the myodural bridge may play a vital physiological role. It is possible, for instance, that the prevention of spinal dura mater infoldings might be involved in regulated cerebrospinal fluid circulation. For instance, it is possible to prevent spinal dura mater infoldings, regulating cerebrospinal circulation. Bats are nocturnal and the only mammals that can perform a genuine and sustained flight, whereas tree shrews are arboreal mammals that often climb to a high altitude of about 10,000 feet. Both animals have lifestyles that are different from other previously studied mammals. The study of these two animals will shed further light on the existence of the myodural bridge in mammals. Gross anatomical dissection was used to observe the connections between the deep muscles of the neck and the dura mater at the level of the atlanto-occipital interspace. The existing structures were analyzed using conventional and special histological staining techniques. The suboccipital regions in bats and tree shrews contained the rectus capitis dorsal major (RCDma), rectus capitis dorsal minor (RCDmi), oblique capitis anterior (OCA), and oblique capitis posterior (OCP). Dense connective tissue connects the RCDmi to the posterior atlanto-occipital membrane (PAOM) and the latter to the spinal dura mater. The myodural bridge in these mammals shares a similar structure to the myodural bridge in humans. Histological analyses confirmed that the connective fibers of the myodural bridge were primarily type I collagen fibers. In this study, it is supplemented by the existence of the myodural bridge in mammals. This further demonstrates that myodural bridge widely exists in the normal anatomy of mammals. This provides morphological support for a comparative anatomical study of the physiological function of the myodural bridge.

El puente miodural es un tejido conjuntivo denso que conecta los músculos y los ligamentos a la duramadre espinal en el espacio atlanto-occipital. Algunos investigadores creen que el puente miodural puede desempeñar un papel fisiológico vital. Es posible, por ejemplo, que la prevención de los pliegues de la duramadre espinal pueda estar involucrada en la circulación regulada del líquido cefalorraquídeo. En esta instancia, es posible prevenir los pliegues de la duramadre espinal, regulando la circulación cerebro espinal. Los murciélagos son animales nocturnos y los únicos mamíferos que pueden realizar un vuelo real y sostenido, mientras que las musarañas arborícolas son mamíferos arbóreos que a menudo ascienden a una gran altura de unos 10 000 pies. Ambos animales tienen estilos de vida diferentes a los de otros mamíferos previamente estudiados. El estudio de estos dos animales ofrecerá más información sobre la existencia del puente miodural en los mamíferos. Se realizó una disección anatómica macroscópica para observar las conexiones entre los músculos profundos del cuello y la duramadre a nivel del espacio atlanto-occipital. Las estructuras existentes se analizaron mediante técnicas de tinción histológica convencionales y especiales. Las regiones suboccipitales en murciélagos y musarañas arbóreas presentaban el músculo recto dorsal mayor de la cabeza (RCDma), el recto dorsal menor de la cabeza (RCDmi), el oblicuo anterior de la cabeza (OCA) y el oblicuo posterior de la cabeza (OCP). El tejido conjuntivo denso conecta el RCDmi con la membrana atlanto- occipital posterior (PAOM) y esta última con la duramadre espinal. El puente miodural en estos mamíferos comparte una estructura similar al puente miodural en humanos. Los análisis histológicos confirmaron que las fibras conectivas del puente miodural son principalmente fibras de colágeno tipo I. Esto demuestra además que el puente miodural existe ampliamente en la anatomía normal de los mamíferos. Esta investigación proporciona apoyo morfológico para un estudio anatómico comparativo de la función fisiológica del puente miodural.

Diagnosis of Trichoepithelioma in a Tree Shrew and Observation of Cell Biological Characteristics / 实验动物与比较医学

ObjectiveTo observe the primary tumor of tree shrews and to provide a basis for studying the pathogenesis and prevention of trichoepithelioma. MethodsA tumor was discovered in the chest and abdomen of a tree shrew during natural cultivation. The tree shrew was anesthetized, and the tumor was surgically removed. Hematoxylin and eosin (HE) staining and immunohistochemical staining were performed on the tumor tissue after paraffin section, and the tumor cells were isolated and cultured by passage. The isolated tumor cells were subcutaneously injected into healthy tree shrews and nude mice. The tumorigenesis of tumor cells in vivo was observed once a day, with nude mice continuously observed for 2 months and tree shrews observed for more than 6 months. ResultsHE staining showed that the basal cells in the dermis were arranged as a whole, like a string of petals, forming nests and stripe-like structures with clear boundaries. The observation results after magnification revealed that the tumor cells were arranged in a pallisade-like and basal pattern, with deep nuclear staining and minimal cytoplasmic. Immunohistochemical staining showed the high expression of CK protein and low proportion expression of ki-67 protein in tumor cells, as well as the high expression of vimentin and low expressions of Bcl2 and CD10 in tumor cell mesenchyme. The isolated tumor cells grew well in DMEM medium containing 10% fetal bovine serum and could be cultured by passage, but no tumor formation was observed in healthy tree shrews and nude mice inoculated with tumor cells. ConclusionCombined with the location of the tumor, overall morphology, HE staining, and immunohistochemical results, the thoracoabdominal mass of the tree shrew was diagnosed as a trichoepithelioma.

Establishment of experimental bacterial keratitis in a tree shrew infection model and expression of interleukin-17 in the model / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To establish the model of pseudomonas aeruginosa and staphylococcus aureus keratitis infection in tree shrews. To determine the expression of IL-17 in the bacterial infection process of tree shrews cornea, and the mechanism of IL-17 in bacterial keratitis of tree shrews is discussed.<p>METHODS: The tree shrew bacterial keratitis models were established by the contact lens-assisted corneal scratching method. After establishing models successfully, the infection symptoms of the model were evaluated by using anterior segment photography and <i>in vivo</i> confocal microscopy on 1, 4, 7 and 14d after performing inoculation, and pathological sections were made to observe histopathological changes in the cornea. Samples were collected at the corresponding time points above, and the expression of IL-17 mRNA in the corneal tissues of tree shrews was detected by real-time quantitative PCR, and the expression of IL-17 protein was detected by ELISA.<p>RESULTS:The success rate of modeling the tree shrew pseudomonas aeruginosa and staphylococcus aureus keratitis models was 96% and 100%.The clinical manifestations and inflammatory cell infiltration of the tree shrew keratitis was consistent with the changing rules of the cornea in histopathological. IL-17 gene and protein expression profiles in tree shrew corneas were consistent with the severity of corneal inflammation basically. <p>CONCLUSION:The use of contact lens-assisted corneal scratching method can successfully establish animal models of pseudomonas aeruginosa and staphylococcus aureus keratitis in tree shrews that more closely resemble the natural course of human bacterial keratitis infection. IL-17 participated in the occurrence and development of bacterial keratitis in tree shrews.

Effect of umbilical cord mesenchymal stem cell transplantation for treating systemic lupus erythematosus in a tree shrew model / 中国组织工程研究

BACKGROUND: Systemic lupus erythematosus is an autoimmune disease with unknown causes. To establish a tree shrew model of systemic lupus erythematosus is helpful to understand its pathogenesis and provide evidence for stem cell transplantation in the treatment of autoimmune diseases. OBJECTIVE: To establish a tree shrew model of systemic lupus erythematosus and to assess the therapeutic effect of umbilical cord mesenchymal stem cell transplantation. METHODS: Tree shrews were grouped and intraperitoneally injected pristane, lipopolysaccharide, and their combination. At 3 weeks after injection, 12 tree shrew models were divided into treatment group and model control group (n=6 per group). An additional 6 models were selected as a normal control group. In the treatment group, each tree shrew was injected with 1×106 DiR-labeled umbilical cord mesenchymal stem cells through caudal vein. Two weeks later, the heart, liver, spleen, lung and kidney of tree shrews were taken for pathological sections. The sections received hematoxylin-eosin staining, kidney Masson staining and immune complex detection. Simultaneously, the heart, liver, spleen, lung and kidney of the three groups of tree shrews were taken for in vitro imaging. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining showed pathological changes of the heart, liver, spleen, lung and kidney in the model control group; and there were a lot of immune complex deposits in renal tissue in the model control group. The pathological changes in the treatment group improved, and the structure recovered to close to the normal control group. (2) In vitro imaging showed that DiR-labeled cells were mainly distributed in the lung, liver and spleen of the tree shrews in the treatment group. The fluorescence intensity of tree shrews in the treatment group was significantly higher than that in the normal control group and model control group (P < 0.05). (3) Results demonstrated that intraperitoneal injection of pristane and lipopolysaccharide is the best method to induce pathological changes of systemic lupus erythematosus in tree shrews. The pathological changes after treatment with umbilical cord mesenchymal stem cells have improved, indicating that umbilical cord mesenchymal stem cells have certain treatment effects on tree shrew models of systemic lupus erythematosus.

Allogeneic umbilical cord mesenchymal stem cell transplantation for metabolic syndrome in a tree shrew model / 中国组织工程研究

BACKGROUND: Current treatments for metabolic syndrome are comprehensive treatments with drugs, aiming to improve patient’s life. Patients are required to have a high compliance to follow-up and have developed various adverse reactions. Therefore, there is no treatment to fundamentally delay the development of metabolic syndrome. OBJECTIVE: To establish a tree shrew model of metabolic syndrome and evaluation techniques, and to explore the therapeutic effect of umbilical cord mesenchymal stem cells in the tree shrew model, providing theoretical basis and reference method for clinical application of stem cell transplantation in metabolic syndromes. METHODS: Umbilical cord mesenchymal stem cells of tree shrews were obtained by adherent culture method, and met the biological characteristics of umbilical cord mesenchymal stem cells. The dark red fluorescent iodide DIR was used to label tree umbilical cord mesenchymal stem cells. Thirty-two tree shrews were fed high-sugar, high-cholesterol, high-salt diet and syrup diet, and injected streptozotocin to make metabolic syndrome models. Animal models were randomly divided into model control group (n=10) and cell treatment group (n=22). In the cell treatment group, the umbilical cord mesenchymal stem cells labeled in vitro were injected into the tail vein, and the model group was injected an equal volume of physiological saline in the meanwhile. Blood biochemical indicators, glucose tolerance, insulin resistance index and arterial blood pressure were measured after transplantation. RESULTS AND CONCLUSION: The tree shrew model of metabolic syndrome was successfully constructed, showing obvious insulin resistance, hyperglycemia, lipid metabolism disorder, and hypertension, which met the diagnostic criteria of metabolic syndrome. Umbilical cord mesenchymal stem cells transplantation could significantly reduce the blood glucose and blood lipid levels, improve insulin resistance and regulate insulin secretion in the tree shrew model of metabolic syndrome. Transplanted umbilical cord mesenchymal stem cells could be homing to the liver, kidney and pancreas of the tree shrew model of metabolic syndrome, and produce certain repairing effects.

Resina draconis inhibits the endoplasmic-reticulum-induced apoptosis of myocardial cells via regulating miR-423-3p/ERK signaling pathway in a tree shrew myocardial ischemia– reperfusion model

Ischemia-reperfusion (IR) is one of the significant medical problems in China. Triphenyltetrazolium chloride (TTC) stainingis used to detect the status of the infarct size, and real-time PCR and western blotting are used to detect expressions ofgenes. TUNEL assay has been used to detect apoptosis. Using a tree shrew myocardial IR model, we found that in thereperfusion period, resina draconis (RD) treatment reduced the infarct size by TTC staining, and significantly enhanced thesuperoxide dismutase expression and down-regulated the malondialdehyde concentration in a dose-dependent manner. Inhearts showing IR, Bax was increased and Bcl-2 was reduced, and RD treatment inhibited the IR-induced Bax expressionand up-regulated the IR suppressed level of Bcl-2. TUNEL assay showed that IR induced the apoptosis of myocardial cells,and RD treatment suppressed the IR-induced apoptosis. CHOP and GRP78 were also upregulated in IR hearts, and RDtreatment could significantly attenuate the CHOP and GRP78 levels compared with IR group. We further found that IRdecreased the miR-423-3p expression and upregulated its target gene ERK both in mRNA and protein levels, and RDtreatment upregulated miR-423-3p expression and downregulated ERK expression compared with the IR group. Importantly, miR-423-3p mimics inhibited IR increased ERK, CHOP and GRP78 expressions, and enhanced IR decreased Bcl-2expression, and inhibited the IR-induced apoptosis of myocardial cells. The findings of this study suggest that RD treatmentinhibited the endoplasmic reticulum induced apoptosis of myocardial cells via regulating miR-423-3p/ERK signalingpathway in a tree shrew myocardial IR model.

Comparison of modeling effects of two different 7, 12-dimethylbenza anthracene induced breast cancer models in tree shrew / 中华肿瘤杂志

Objective@#To explore the feasibility of 7, 12-dimethylbenz[a] anthracene (DMBA) induced tree shrew breast cancer model, and compare the effects of two administration modes by gavage and mammary gland injection.@*Methods@#A total of 40 tree shrews were randomly divided into two groups (20 animals per group): DMBA gavage group and mammary gland injection group. DMBA was dissolved in edible vegetable oil. For gavage group, tree shrews were administered with DMBA solutions (15 mg/kg) by gavage once a day. For mammary gland injection group, DMBA solution (10 mg/kg) was injected into the mammary fat pad of tree shrews, and the injection was performed for a total of 3 times. From the first administration of DMBA, medroxyprogesterone acetate (MPA, 100 mg/kg) was intramuscularly injected into the muscles of the lateral thighs of tree shrews at the same time, for a total of 5 times. The tumorigenesis and survival of tree shrews were monitored. The tumor histological morphology was observed by HE staining. The expression of estrogen receptor (ER), progesterone receptor (PR), cytokeratin5/6 (CK5/6) and human epidermal factor receptor-2 (HER-2) was detected by immunohistochemical staining.@*Results@#In the gavage group, there were 10 deaths, and 4 tree shrews developed mammary tumors with 20.0% (4/20) tumor formation rate. The success rate of mammary cancer modeling was 10.0% (2/20), and the tumor formation time was 197.3±15.1 days. In the mammary gland injection group, there were 8 tree shrews died, and 9 tree shrews formed tumors with 45.0% (9/20) tumor formation rate. The success rate of mammary cancer modeling was 40.0% (8/20), and the tumor formation time was 71.8±19.0 days. There was no significant difference in mortality and tumor formation rate (P>0.05) between the two groups (all P>0.05). However, in the mammary gland injection group, the success rate of mammary cancer modeling was significantly higher than that in the gavage group (P<0.05), whereas the tumor formation time was markedly shorter than that in the gavage group (P<0.01). The pathological types in the gavage group included ductal hyperplasia, intraductal papilloma and ductal carcinoma in situ, while those in the breast injection group included intraductal papilloma and ductal carcinoma in situ. In both groups, immunohistochemical staining showed the negative expression of HER-2 but positive expression of ER, PR and CK5/6 with varying degrees.@*Conclusion@#Both the DMBA gavage and mammary gland injection can successfully establish the tree shrew breast cancer model, and the modeling effect of mammary gland injection is better than gavage.

Construction of real-time polymerase chain reaction detection for infection-related cytokines of tree shrew / 生物医学工程学杂志

Tree shrew is a novel and high-quality experimental animal model. In this study, the real-time polymerase chain reaction methods were established to detect infection-related cytokines interleukin-6 (IL-6), IL-8, IL-10, IL-17A, interferon-γ (IFN-γ) and housekeeping gene glyceraldehyde-phosphate dehydrogenase ( ) of tree shrew. The results indicated that the establised methods had good specificity. The high point of the linear range of these reagents reached 1 × 10 copies, and the low points ranged from 10 copies (IL-6, IL-17A), 100 copies (IL-10, ) to 1 000 copies (IL-8, IFN-γ). In this interval, the linear correlation coefficient of each reagent was greater than 0.99. The lowest detectable values of IL-6, IL-8, IL-10, IL-17A, IFN-γ and were 8, 8, 4, 8, 128 and 4 copies, respectively. The results showed that the established detection methods had good specificity, sensitivity and wide linear range. The methods were suitable for detection of multiple concentration range samples, and could be used for the subsequent studies of tree shrew cytokines.

Serum epidemiology of five strong pathogenicity human adenoviruses natural infection in Tupaia belangeri / 中国人兽共患病学报

In order to explore the possibility of human adenovirus infection with tree shrews,the neutralizing antibody ti-ters of five kinds of human adenoviruses (HAdv)in the serum of tree shrews were analyzed.The levels of Ad3,Ad4,Ad7, Ad14 and Ad55 neutralizing antibody were detected by virus neutralization test.The results showed that the positive rate of four adenoviruses in group B were higher than Ad4 in group E,and the positive rates respectively were Ad14 (55.88%),Ad3 (47.06%),Ad55 (29.71%),Ad7 (14.71%)and Ad4 (8.82%).The antiserum mainly mixed with Ad3,Ad14 and Ad55 anti-body.Five species of human adenovirus can be naturally infected with tree shrews.Tree shrews are used as experimental ani-mals to establish human adenovirus infection model is alternative.

Characteristics and changes of the CD molecules and IFN-γ expressions in tree shrews infected with mammalian orthoreovirus / 中国实验动物学报

Objective To explore the characteristics of immunological changes in tree shrews infected with orthoreovirus, and provide a theoretical basis for the prevention of virus in tree shrews. Methods 40 -50-day-old tree shrews were divided into three groups: MRV1/TS/2011 virus-infected and MRV3/TS/2013 virus-infected groups, and saline-treated control group. On the 1, 8, 14, 21, and 28 days after infection, blood samples were taken from the tail vein and used for RT-PCR, flow cytometry and ELISA detection, to assess the viral load, number of CD4/CD8/CD19 cells, and IFN-gamma expression. Results The MRV1/TS/2011 and MRV3/TS/2013 viral load in the plasma and the number of CD4 +and CD19 +cells reached a peak at the 14th day after infection. At the first day after MRV1/TS/2011 infection, the CD4 +cells had a significantly higher expression compared with the normal group. CD8 +cells and the IFN-gamma expression reached a peak at the 21st day after infection. The expression of CD4 +was even higher after MRV1/TS/2011 infection, and the expression of CD8 +cells was higher after MRV3/TS/2013 infection. Conclusions We would conclude that after MRV1/TS/2011 and MRV3/TS/2011 virus infection, accompanying the changes of viral load, it shows some regularity of the expression of CD4/CD8/CD19 and IFN-gamma in the tree shrews: at the early stage of MRV1/TS/2011 virus infection, humoral immunity is stimulated, and CD4 +cells play a major role. MRV3/TS/2013 virus may mainly affect the cellular immunity, while humoral immunity only plays a role at a high viral expression or the late stage of infection. CD4 +cells may be more sensitive to type 1 reovirus, and CD19 +cells may be more sensitive to type 3 reovirus.

Establishment and application of a TaqMan real-time fluorescence quantitative PCR for detection of tree shrew adenovirus(TAV) / 中国比较医学杂志

Objective To establish a quick and accurate method for detection of tree shrew adenovirus(TAV) using TaqMan real-time fluorescence quantitative PCR. Methods Based on the published TAV genome sequence, a 3' conserved sequence was used to design specific probe primers. A standard curve was prepared using a recombinant plasmid containing the target gene fragment. A real-time fluorescence quantitative PCR method was established for detecting TAV based on TaqMan probe. Results The detection method was specific and was not cross-reactive with other common pathogens. The detection limit of the method was 3.7 copies/μL,showing a high sensitivity. The correlation coefficient was 0.998, and the efficiency was 95.7%. The amplification result showed a fine linear relationship,and the repeatability test effect was good. Conclusions The TAV real-time quantitative PCR detection method based on TaqMan probe has been successfully established. It has high sensitivity and reproducibility and can be applied to early detection of TAV infection.

Establishment and application of a PCR detection method for Tupaia (tree shrew)paramyxovirus(TPMV) / 中国比较医学杂志

Objective To establish and preliminarily apply an effective PCR assay for detection of Tupaia(tree shrew)paramyxovirus(TPMV). Methods Using TPMV genomic DNA from NCBI GenBank, bases 8231 to 8720 were synthesized and inserted into a plasmid as a positive standard. One primer pair was designed based on this sequence. In total,60 respiratory swabs and 12 lung tissues from the tree shrews were tested in this PCR assay. Results A PCR method for detection of TPMV was successfully established,with high specificity and sensitivity of 11.5 × 10 -5μg/mL. PCR result testing 60 respiratory swabs and 12 lung tissues were negative. Conclusions PCR for detecting TPMV has good specificity and high sensitivity and can be used for conventional tree shrew paramyxovirus detection.

Research advances of application of tree shrew as an animal model of viral infectious diseases / 中国比较医学杂志

Viral infection is the main death cause of infectious diseases in China. The establishment of an animal model to mimic the progression of viral infectious diseases in humans is of great significance to the study of pathogenesis and prevention of viral infectious diseases. As a new animal model established and developed in recent years, tree shrew has showed obvious advantages and potentials compared with other non-human primates and mice which are commonly used as virus-infected animal models. In this paper, the biological advantages of tree shrew as a novel animal model of viral infectious diseases are summarized, including taxonomy, physiology and immunology. In addition, the latest application of tree shrew in the research of many viral infectious diseases such as hepatitis virus, herpes simplex virus, influenza virus and enterovirus infections are compared and summarized.

Study on model of tree shrew induced by chronic corticosterone injection in anxious depression / 中国药理学通报

Aim To investigate the effects of chronic corticos-terone injection on anxiety and depression-like behavior of tree shrews, evaluate the predictability of drug and establish a novel animal model of anxious depression .Methods Twelve Chinese and Burma tree shrews were randomly divided into normal group, model group and venlafaxine group .The anxious depres-sion model of tree shrew was established by chronic corticoster-one injection ( ih, 27 mg· kg-1 , 21 d) .The venlafaxine group received intragastric administration (6 mg· kg-1).Autonomous activity score, sugar water preference test and Morris water maze test were used to evaluate the anxiety and depression-like behav-ior of tree shrews .The expressions of CRH , ACTH and COR in the tree shrew plasma were determined by Elisa kit .The con-tents of monoamine neurotransmitters of tree shrews in the hippo-campus , amygdala and prefrontal cortex were detected by HPLC-ECD.Results Compared with the normal group , the autono-mous activity score , sugar water partial eclipse degree and the learning and memory ability significantly decreased (P<0.01), while the contents of CRH , ACTH and COR significantly in-creased ( P<0.05) , and the contents of 5-HT, NE and DA in the hippocampus , amygdala and prefrontal cortex declined in the model group(P<0.05).In the venlafaxine group, the learning and memory abilities of the tree shrews were improved , the lev-els of CRH and COR in plasma were significantly decreased ( P<0.05), and the contents of 5-HT, NE and DA were increased (P<0.05).Conclusions The tree shrews of anxious depres-sion have obvious HPA axis hyperactivity and monoamine neuro-transmitter disorder , and venlafaxine can reverse this phenome-non, indicating that the tree shrews model of anxious depression has drug predictability , which is a kind of novel animal model of anxious depression closer to human in clinic .

Super-Resolution Track-Density Imaging Reveals Fine Anatomical Features in Tree Shrew Primary Visual Cortex and Hippocampus / 神经科学通报·英文版

Diffusion-weighted magnetic resonance imaging (dMRI) is widely used to study white and gray matter (GM) micro-organization and structural connectivity in the brain. Super-resolution track-density imaging (TDI) is an image reconstruction method for dMRI data, which is capable of providing spatial resolution beyond the acquired data, as well as novel and meaningful anatomical contrast that cannot be obtained with conventional reconstruction methods. TDI has been used to reveal anatomical features in human and animal brains. In this study, we used short track TDI (stTDI), a variation of TDI with enhanced contrast for GM structures, to reconstruct direction-encoded color maps of fixed tree shrew brain. The results were compared with those obtained with the traditional diffusion tensor imaging (DTI) method. We demonstrated that fine microstructures in the tree shrew brain, such as Baillarger bands in the primary visual cortex and the longitudinal component of the mossy fibers within the hippocampal CA3 subfield, were observable with stTDI, but not with DTI reconstructions from the same dMRI data. The possible mechanisms underlying the enhanced GM contrast are discussed.

Plasticity of the visual cortex area 17 after form deprivation in tree shrews / 中国实验动物学报

Objective To preliminarily explore the feasibility of tree shrew as a new kind of animal model in research of amblyopia,to discuss the primary visual cortex plasticity mechanism of form deprivation in tree shrew,and to provide a theoretical basis for further understanding the mechanism of amblyopia formation and recovery.Methods Sixty 30-days old tree shrews were divided into five groups,12 in each group:the group A had the right eye sutured for 1 month;the group B had the right eye sutured for 2 months;the group C had the left eye sutured for 1 month and then opened and the righ eye was sutured for 1 month,in other words,the group C was performed by alternating suture;the tree shrews of control group 1(D1) were in the same age as the the group A,but fed in normal breedingenvironment;the tree shrews of control group 2(D2) were at the same age of groups B and C,but fed with a normal diet.Samples of the visual cortex were taken after the completion of modeling,and were processed to observe the histology and ultrastructure of the visual cortex,the neuron apoptosis,and the c-fos protein expression in the tree shrews of different groups.Results Damages to different degrees were found by histological and electron microscopic examination of the visual cortex in each experimental group,and they were more obvious in the group sutured for 2 months.TUNEL staining showed that there were no significant differences between the apoptosis in the experimental and control groups.The expression of c-fos mRNA and protein in the experimental groups was decreased,and it was the lowest in the group sutured for 2 months.There was a small increase in the c-fos expression after the alternate suture,and no significant difference of c-fos expression was found in the control groups.Conclusions Different degrees of deprivation amblyopia lead to different histopathological changes.There is a plasticity in the neurons affected by amblyopia.Tree shrew can be used as an ideal animal model for the studies of form deprivation amblyopia.

Establishment of a EV71 virus infection model of tree shrew primary renal cells / 中国实验动物学报

Objective To establish an enterovirus 71(EV71) infection model of tree shrew primary renal cells.Methods Tree shrew primary renal cells were obtained by trypsin digestion.After subculture and purification,EV71 virus was used to infect these primary cells.The culture supernatant of these EV71-infected cells was collected for virus titer detection at 1,2,4,6 and 8 days post-infection.The cells were collected for detection of EV71 VP1 protein by Western blot assay.Furthermore,the expression and location of VP1 protein in the infected cells were detected by indirect immunofluorescence assay.Vero cells were taken as positive control to evaluate the infectivity of EV71 virus to tree shrew primary renal cells.Results Morphologically,the cultured cells were proved to be majorly consisted of the primary renal cells after subculture and purification.The obtained primary cells were infected by EV71 virus.The virus titer was up to 1.3×106 TCID 50/mL during 48-96 h post-infection,proving that EV71 virus infected and proliferated in the tree shrew primary renal cells.Western blot showed that the viral VP1 protein was detected from infected primary cells at 2 to 8 d post infection.VP1 protein was also observed in the cytoplasm at 2 to 6 d post infection by indirect immunofluorescence.Compared with Vero cells,the infectivity of EV71 virus to tree shrew primary renal cells and its proliferation were confirmed.Conclusions Based on the successful establishment of cell culture of tree shrew primary renal cells,the infectivity to the obtained cells and proliferation of EV71 virus in the cells are confirmed.The model of EV71 virus-infected tree shrew primary renal cells is initially established.

Mechanism of ischemic postconditioning relieved brain edema and cerebral infarction after cerebral ischemia in tree shrews / 解剖学报

Objective: To observe the effects of ischemic postconditioning (PC) on changes of cerebral water content, cerebral blood flow, infarct area and hippocampal ultrastructural, and to explore the neuroprotective mechanisms of ischemic PC on undergoing thrombotic cerebral ischemic injury. Methods: Tree shrews were randomly grouped into control, ischemia 4 hours, ischemia 24 hours, ischemic postconditioning 4 hours and ischemic postconditioning 24 hours (n = 8) Eight animals were used for HE staining(n = 3) and electron microscopy(n = 5). The model of thrombotic cerebral ischemia was induced by photochemistry in tree shrews. Four hours after the model establishment, the common carotid artery on the ischemia side was clamped for 5 minutes, then perfused by removing the clamp for 5 minutes, and repeated the same management 3 times, so that the model of PC was established. The changes of the brain water content of local cortex were measured by Elliott dry-wet weight and the brain infarct area was determind by 2,3,5-triphenyl-tetrazolium chloride staining. In addition, the regional cerebral blood flow of local cortex was measured by laser doppler, and the ultrastructural changes in the CA1 area of hippocampus in different groups were observed under an electron microscope. Results: More neuron pycnosis was observed in hippocampal CA1 area. Obvious swelling of mitochondria, partial disrupt and vanish of the mitochondria cristae and more endoplasmic reticulum cisterna appeared in the neuron of hippocampus at the 24th hour after cerebral ischemia. With the time prolonging of ischemic, the brain water content was significantly increased (86. 81% ± 1. 08%) in the ischemia group at the 24th hour compared with sham group. Cerebral infarction area was maximum (33.00% ±3.03%) and regional cerebral blood flow decreased obviously [(134. 27 ±28.75) ml/min]. The brain water content was significantly decreased (81. 04% ± 1. 04%, P <0. 01) and the infarct area was significantly shrink in ischemic postconditioning group (16. 79% ± 1. 29%, P < 0. 01) than that in ischemia group. The regional cerebral'blood flow in ischemic postconditioning group was in contrast to ischemia group significantly at the 24th hour [(195. 25 ±21. 18) ml/min, P<0.01]. Conclusion: Ischemic postconditioning attenuates the edema in ischemic brain and narrow the cerebral infarction area in tree shrews. The mechanism may be related to the improvement of local cerebral blood flow.

Study of two kinds of Alzheimer's disease tree shrew models / 中国药理学通报

Aim To explore the optimized tree shrews model of Alzheimer's disease through comparison of the pathology changes of brain neurons between the two kinds of tree shrew models.Methods Fifty tree shrews were randomly divided into five groups with 10 in each group:control group,high dose D-galactose combined with ibotenic acid (IBO) group,low dose D-galactose combined with IBO group [intraperitoneal injection D-galactose combined with IBO injection into bilateral basal nucleus of Meynert (BNM)],high dose Aβ25-35 combined with IBO group,and low dose Aβ25-35 combined with IBO group (injection into bilateral BNM).Hematoxylin and eosin (HE) staining was used to observe the morphological changes of brain neurons.The expressions of choline acetyltransterase (ChAT) and synaptophysin(SYP) in the brains were detected by immunohistochemical staining.Western blot was used to detect the expression of amyloid beta 1-42 (Aβ1-42),amyloid precursor protein (APP) and phosphorylated tau protein (p-tau).Results The HE staining showed there were different degrees of morphological changes in the brains of model groups.The changes in the high dose D-galactose and high dose Aβ25-35 combined with IBO group were more obvious than those in low dose D-galactose and Aβ25-35 combined with IBO group.Immunohistochemical staining revealed that the levels of ChAT and SYP in the model groups decreased compared with control group,and the decline in high dose Aβ25-35 combined with IBO group was more marked than that in low dose Aβ25-35 combined with IBO group(P ＜0.01).Western blot revealed that the levels of Aβ1-42,APP,p-tau in the model groups increased compared with control group,and the rise in high dose Aβ25-35 combined with IBO group was more apparent than that in low dose Aβ25-35 combined with IBO group (P ＜ 0.05 or P ＜ 0.01).Conclusion The method of modeling by Aβ25-35 combined with IBO injection into bilateral BNM is more suitable for the establishment of Alzheimer's disease model.

Establishment of a tree shrew model of Fusarium keratitis / 中国实验动物学报

Objective To establish a tree shrew model of Fusarium solani keractitis by injecting Fusarium solani conidia into the corneal stroma.Methods Fusarium solani was inoculated into Sabouraud culture medium and incubated at 26℃ for 7 days.Fungal suspension was collected and the number of spores was adjusted to 1 × 1010 CFU /mL on the blood cell count plate.Forty healthy tree shrews were randomly divided into experimental group (n=30) and control group (n=10).In the experimental group, 50 μL of fungal spore suspension was injected into the cornea center with a 29G needle, and 50 μL saline was injected in the control group.The models were evaluated by anterior segment photography, in vivo confocal microscopy, histopathology, and corneal tissue culture.Results The fungal infiltration, the degree of edema of corneal epithelial and endothelial cells, and the number of mycelium were positively correlated with time.The number of infiltrating inflammatory cells, mainly, neutrophils, reached a peak on the 7th day after modeling.The mycelial growth was parallel to the stromal fibers.After the successful establishment of the model, the corneal tissue culture showed the growth of Fusarium solani.The successful rate of modeling was 86%.Conclusions The tree shrew model of Fusarium solani keratitis is established by injecting spores of Fusarium solani into the cornea.