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Objective To analyze the neuroimaging changes of tree shrew models of Alzheimer’ s disease.Methods Nineteen healthy adult female tree shrews were randomly divided into control (5 animals) and model group (14 animals). The model of Alzheimer’s disease was induced by intracerebroventricular injection of Aβ1-40 using a stereotaxic devise and proved successfully by visuospatial congnitive task.The in vivo microstructural changes in the brain of tree shrew AD models and control group (0, 1, 2, 3, 4 weeks) were observed on 1.5T MRI (T2WI), and on 7.0T MRI (12 week)(T2WI, DTI). Results Reference memory errors were increased in the model group at 3 or 4 weeks (P<0.05), and so working memory errors (P<0.05) and period of time to perform (P<0.05, P<0.05, P<0.01) from 2 to 4 weeks.Thus the model was proved to be established successfully.T2WI test and DTI test were carried out.Hippocampus atrophy of the model group at 3 and 4 weeks was observed compared with that at 0 or 1 week or 2 weeks on a 1.5T Philips Gyroscan.Compared with the control group, the temporal horn width in the model group was significantly increased (P<0.01) at 12 weeks on a 7.0T Bruker Biospec Scanner.DTI test at 12 weeks showed that ADC of bilateral hippocampus was up-regulated in the model group ( P<0.01 ) .In the color coded orientation view, loss of the corpus callosum fibers was obvious in the model group. Conclusions Intracerebroventricular injection of Aβ1-40 can lead to learing and memory impairment in tree shrews.There are abnomal MRI signal changes in the brain, and the temporal horn width, hypocampal apparent diffusion coefficient ( ADC) value and corpus callosum damage may provide reference value for the diagnosis of Alzheimer’ s disease.
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Objective To establish a tree shrew mode of breast tumor.Method Forty-five 3 to 4 month-old female tree shrews were orally gavaged with 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) or peanut oil per animal for three times.Following that, fifteen DMBA administrated tree shrews were implanted 90 day-release medroxyprogesterone acetate ( MPA) pellets.The tree shrews were palpated once weekly to detect mammary tumors for 45 weeks after first DMBA administration.Results DMBA were able to induce breast tumors (12.5%) in tree shrews, and MPA increased the tumor incidence (50%) while no breast tumors were observed in the control group.Three induced breast tumors were intraductal papillary carcinomas and one was IDC by H&E stain.Conclusion All induced tumors are similar with spontaneous tumors in structure and molecular markers.
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Objective To investigate the expression levels of BDNF, trkB and ChAT mRNA and proteins in the brain of adult tree shrews ( Tupaia belangeri ) .Methods Quantitative real-time PCR was employed to detect the expression levels of BDNF, trkB and ChAT mRNA in the hippocampus, basal ganglia and frontal cortex of adult tree shrews.The expression levels of BDNF, trkB and ChAT proteins andβ-actin was used as internal standard.Results The expression level of BDNF mRNA was highest in the hippocampus of adult tree shrew, and there were significant differences between that in the hippocampus, and basal ganglia and frontal cortex (P0.05) in the expressions of trkB protein among the hippocampus, basal ganglia and frontal cortex of the adult tree shrews.There were no significant differences in expressions of ChAT mRNA and protein among the hippocampus, basal ganglia and frontal cortex in adult tree shrews ( P>0.05 ) . Conclusions The expression levels of ChAT mRNA were consistent with that of ChAT protein in the hippocampus, basal ganglia and frontal cortex of adult tree shrews, while the expression levels of BDNF and trkB mRNA were not consistent with their proteins, which might indicate that the transcriptional regulation pattern might be more complex.Tree shrew is a valuable animal model in the study of mechanism of BDNF/trkB gene expression.
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Objective To lay the physiological and biochemical basis for establishing and evaluating tree shrews model of human disease. Methods There were 92 Tupaia belangeri chinensis, in which half of them were male,they were allowed to eat nothing for 12 hours, then we sampled heart blood 0.8~1.0 mL without anesthesia and put blood samples into sterilized centrifuge tube for separation and preparation of serum. Olympus AU5400 automatic biochemistry analyzer was used to measure biochemical indexes. Then 1.5~2.0 mL of urine of each tree shrew was collected and put into sterilized centrifuge tube for measuring renal function by using Combi-scan500 urine analyzer. Fianally SPSS statistics software was used to analyse the measured values, and comapared the measured values with the human reference values. Results There were significant differences in myocardial enzymes and some renal function indexes such as lactic dehydrogenase,α- hydroxybutyric, acid dehydrogenase, creatinine, uric acid, urine specific gravity and pH value between male and female Tupaia belangeri chinensis ( 0.05) . Then determination value of Tupaia belangeri chinensis, male’s and female’s, myocardial enzyme and part of the renal function indexes were compared with the human reference values. Some indexes including urea, urine specific gravity, urine, urobilinogen were in the range of human reference value, while the values of urine bilirubin, urine nitrite. lactate dehydrogenase, creatine kinase, α-hydroxybutyrate dehydrogenase, creatine kinase isoenzyme CKMB were higher than the human reference value. White blood cell, urine protein, ketone, occult blood most of them were negative as the same to human reference value, but sometimes were positive, and the positive rates respectively were 3.95%and 46.1%,39.5%,2.63%. The measured value of Vitamin C was positive that is completely opposite to human reference value, but sometimes is negative, the negative rate was 6.6%. Conclusion Urea, urine specific gravity, urine, urobilinogen, urine bilirubin, urine nitrite can be directly used as the indexes for evaluating tree shrews models of human disease, other indexes can be used as indexes for judgment of the normal physiological and biochemical basis of tree shrews.
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Objective To investigate the effect of gastrodin on brain-derived neurotrophic factor (BDNF) expression in Alzheimer's disease ( AD) tree shrew. Methods AD tree shrew model was established by intracerebroventricular injection with amyloid-βpeptide (Aβ) . Since the eighth day after injection, the tree shrews were treated with gastrodin for thirty days. The expression of BDNF in tree threw hippocampus was detected by reverse transcription polymerase chain reaction (RT-PCR) . Results The expression of BDNF mRNA in the treatment group was higher than that in the model group ( <0.05) . Conclusion Gastrodin can increase some degree of the expression of BDNF.