Abstract:ObjectiveTo establish a rat model of myocardial fibrosis and investigate its pathogenetic characteristics, and provide an animal model of myocardial fibrosis (MF) for clinical research. MethodOne hundred male Wistar rats were randomly divided into two groups:the model group (n =92) and the sham group (n=8). The rats in the model group were subjected to heart coronary artery ligation (CAL). Heart specimens were taken at different time points from 1 to 8 weeks. Pathological changes and collagen distribution were examined by histopathology using HE and Masson staining. The hydroxyproline content and expression of collagen and TGF-β1 in the heart tissue were quantitatively determined. The sham operated rats served as controls. ResultsOn the 7th day after CAL, compared with the control rats, the heart tissue of rats in the model group showed seveve inflammatory reaction:disrupture and degeneration of cardiomyocytes, significant increase of collagen content (P<0.01), hydroxyproline content (P<0.05), expression of TGF-β1 (P<0.01), and those changes were kept at a high level during the experiment. The fibrosis reached a peak on the 42nd day, and then it showed a tendency of improvement. No abnormal changes were seen in the myocardium of control rats. ConclusionsA reliable rat model of myocardial fibrosis can be successfully established by coronary artery ligation. Its mechanism may be related to the overexpression of TGF-β1.

Abstract:ObjectiveTo investigate the effect of short-wavelength monochromatic light on refractive development and eye growth in guinea pigs.MethodsTwenty male two-week old guinea pigs were randomly distributed into two groups (n=10 in each group):blue-light group (BL) and white-light group (WL). The BL group was raised under 430 nm monochromatic light, and the WL group was reared under white light with 5000 K color temperature. The light quantum number of the two groups was identical, 3×10-4 μmol·cm-2·s-1. The irradiance value was 0.527 mWcm-2 of blue light and 0.247 mWcm-2 of white light approximately. Biometric and refractive measurements were performed before and after treatment. ResultsBefore treatment, the differences between the biometric parameters of the two groups including refraction, corneal curvature and axial components were not significant (P>0.05). After 12-week exposure, the refraction increased 1.20±0.66 D in the BL group, and decreased 1.18±0.85 D in the WL group. There was a 2.40 D hyperopia in the BL group when compared with that of the WL group(P<0.0001). Meanwhile, the axial length and vitreous body grew 0.77±0.12 mm and 0.05±0.10 mm in the BL group, respectively, and they were extended by 0.95±0.18 mm and 0.21±0.13 mm, respectively, in the WL group. There was a slower speed of axial growth and vitreous body''s extension when compared with that of the control group (P<0.05). No significant differences were found between groups at the end of the research in the radius of corneal curvature, depth of anterior chamber and lens thickness (P>0.05). Conclusions 430 nm short wavelength monochromatic light can slow down the prolongation of axial length and vitreous body and induce hyperopia in guinea pigs.

Abstract:Objective To investigate the feasibility of differentiation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) into cardiomyocytes in vitro and the effects of UC-MSCs transplantation on the mouse models of myocardial infarction.MethodsUC-MSCs were induced by 10 μmol/L 5-aza for 14 days in vitro and then identified by RT-PCR and immunofluorescence staining. The mouse models of myocardial infarction were developed by intraperitoneal injection of isoproterenol hydrochloride (ISO) 3.0 mg/(kg/d). After 48 h, DAPI-labeled UC-MSCs were transplanted via the tail vein twice within 48 to 72 hours in the experimental group. At 4 and 8 weeks after transplantation, the mouse heart and spleen of both groups were taken out. The cardiac index and spleen index of the mouse models were measured, and the differentiation in vivo and the repair of cardiomyocyte injury were evaluated histologically using immunofluorescence and basic fuchsin-picric acid (HBFP) staining, with the mouse models of myocardial injury without UC-MSCs transplantation as control. ResultsRT-PCR analysis showed that the induced cells expressed cardiac-specific genes α-actin, TBX5, GATA4 and NKx2.5. In addition, immunofluorescence staining showed that the induced cells were positive for α-actin and NKx2.5, and some cells showed double nuclei. The models with UC-MSC transplantion were found to have DAPI-positive cardiac cells migrated to the myocardium and showed cardiac α-actin positive at 4 weeks and 8 weeks after transplantation. Obvious therapeutic effect was shown by HBFP staining and by the heart and spleen indexes after UC-MSC transplantation in the myocardial injury mouse models. Conclusions5-azainduced UC-MSCs can be directed to differentiate into cardiomyocytes in vitro, and significant therapeutic effect on the mouse myocardial injury in vivo can be obtained through UC-MSCs transplantation via the tail vein.

Abstract:ObjectiveTo investigate the difference of the gene expression profiles in dormant mouse embryos preserved by controlled slow freezing.MethodsThe differences between gene expression profiles of normal dormant mouse embryos and those preserved by controlled slow freezing were detected by Affymetrix Gene Chip detection. GO bioinformatics and pathway analysis were also applied for further understanding the potential changes of their signaling pathways. ResultsAfter the treatment by controlled slow freezing, a total of 228 genes were changed between these two groups. Among them, 50 genes were up-regulated, and other 178 ones were down-regulated. In addition, the signal pathway analysis revealed that the focal adhesion, ECM-receptor interaction, regulation of actin cytoskeleton, apoptosis, cell communication, ubiquitin-mediated proteolysis, glycerolphospholipid metabolism, small cell lung cancer signaling, TGF-beta signaling, and MAPK signaling pathways were significantly changed. ConclusionsThe results of our study indicate that controlled slow freezing leads to a series of potential changes of gene regulation and signaling pathways in dormant mouse embryos.

Abstract:ObjectiveTo establish a rat model of diet-induced obesity (DIO), and explore its molecular mechanism. MethodsNinty 3-week old male Sprague-Dawley rats in the diet-induced obesity (DIO) experimental group were fed with high fat diet (containing 30% fat) for 25 weeks, and 20 healthy rats in the normal control group were fed with normal diet. The following indicators were evaluated:body weight, Lee''s index, the fasting glucose and insulin levels and pathological changes in the liver tissue. The expression of acetyl-CoA carboxylase (ACC), fatty acid synthetase (FAS), hormone-sensitive lipase (HSL), which are key enzymes in lipid metabolism, and the transcription factor sterol regulatory element binding protein-1c (SREBP-1c) was analyzed by real-time PCR. ResultsDIO rat models were successfully produced by high fat diet for 25 weeks. Compared with the normal rats, after fed with high fat diet for 6 weeks, the DIO rats showed significant increase in the body weight and Lee''s index. After high fat diet for 25 weeks, the DIO rats showed abnormal liver fat accumulation and moderate to severe fatty liver, significant increase in the fasting glucose and insulin levels, and insulin resistance. Real-time PCR results revealed that compared with the normal rats, after feeding with high fat diet for 25 weeks, the expression of ACC, FAS, HSL and the transcription factor SREBP-1c were increased significantly in the liver of DIO rats. The expression of SREBP-1c in the liver of DIO rats was 2.56-fold higher than that of the normal rats. ConclusionsWe have successfully induced normal SD rats to develop diet-induced obesity by feeding high fat diet for 25 weeks. The expressions of lipid metabolism genes SREBP-1c, ACC, FAS and HSL are all involved in the development of DIO, providing an explaination to the relationship between the changes in hepatic lipid metabolism and the development of obesity.

Abstract:ObjectiveTo establish an animal model of Echinococcus muhilocularis (E. m) infection in Cricetulus migratorius, and observe the growth of E. m in the peritoneal cavity of C. migratorius.MethodsC. migratorius was inoculated into the peritoneal cavity in a dose of 2000 cephalomeres of E. m in each animal. The cyst weight and positive antibody were measured, and the cyst weight/body weight ratio was calculated. The growth of E. m was observed in the C. migratorius at 0,5, 8,2, 0,0, 0,0 days after inoculation. Growth and the infection rate of E. m cysts was compared at 100 days after inoculation into 10 animals at a dose of 0,0 or 2000 E. m cephalomeres, respectively. ResultsFifty nine of the 62 C. migratorus were infected by E. m. Mature E. m cephalomeres were observed at 18 days after inoculation and the infection rate reached 100%. Positive antibody was observed at 15 days after inoculation. The cyst weight/body weight ratio was over 15% at 60 days after inoculation. A 100% infection rate was observed at 100 days after inoculation at the three doses. ConclusionsAn animal model of peritoneal Echinococcus muhilocularis infection in Cricetulus migratorius is successfully established, with the characteristics of high infection rate, short period of infection, easy observation of the growth of E. m and antibody titer on these animal models. Sixty days after inoculation of E. m can be used as observation period of the animal modeling in C. migratorius. The cyst weight/body weight ratio, antibody titer and level of cyst growth can be used as the major reference indicators of E. m infection modeling. Females are better than males for making animal models of E. m infection in C. migratorius.

Abstract:ObjectivesTo clarify the effects of IL-21 on cytotoxic effect of SHIV-specific CD8⁺ T cells. Methods Peripheral blood samples were collected from 16 SHIV-infected rhesus monkeys. Real-time fluorescence quantitative RT-PCR assay was used to determine virus load for SHIV RNA, and absolute amount of CD8⁺ T cells were assessed by flow cytometry. The expression of IL-21R, perforin, and CD107a of the CD8⁺ T cells in vitro was assayed by flow cytometry after IL-21 stimulation. CD107a mobilization assay was used to measure the degranulation of CD8⁺ T cells. ResultsIn vivo study indicated a negative correlation between the virus load and the absolute number of CD8⁺ T cells. Compared with the medium control, the expression of IL-21R on the surface of CD8⁺ T cells was significantly increased. Moreover, percentages of both CD107a+ CD8⁺ T cells and perforin+ CD8⁺ T cells were higher than those of the control. ConclusionsAdministration of IL-21 upregulates cytotoxic effect of peripheral CD8⁺ T cells in SHIV-infected rhesus monkeys.

Abstract:Objective The aim of this study was to observe the changes of autonomic nervous function in Wuzhishan minipigs (WZS) and investigate the relationship between dyslipidemia and 24 h or diurnal changes of autonomic nervous function in these animals.MethodsThe WZS minipig models of hyperlipidemia was established by feeding with high fat diet. The serum TG, TC, HDL-C and LDL-C levels were detected and electrocardiogram was monitored by non-invasion telemetry every 2 weeks. 24 h or diurnal autonomic nervous function was evaluated by heart rate variability (HRV) analysis. ResultsThe serum TC, HDL-C, LDL-C levels were significantly increased in the WZS minipigs after feeding with high fat diet for 2 weeks (P<0.01), and TG level was also significantly increased after 6 weeks (P<0.05). Among them, TC and LDL-C levels were rapidly increased during 0 to 4 weeks and reached a high peak at 4 to 6 weeks, and then maintained stable at a certain level during 8 to10 weeks. HDL-C was also rapidly increased and reached a peak during 0 to 2 weeks, and then maintained stable during 2 to 10 weeks. Meanwhile, HRV time-domain analysis indexes ( including RRI, SDNN, RMSSD, SDANN, PNN50, SDANN index, STV, LTV) and HRV frequency-domain analysis indexes (including TP, VLF, LF, HF) were gradually reduced (P<0.05, P<0.01), while LF/HF was significantly increased (P<0.05). The degrees of changes of the HRV parameters were slightly higher in the nighttime than those of daytime. The results of linear correlation analysis showed that there were significant correlations between TC, LDL-C, TC/HDL-C, LDL-C/HDL-C and HRV parameters (P<0.05, P<0.01). Moreover, the multivariate linear gradual regressive analysis also showed that TC, LDL-C, TC/HDL-C, LDL-C/HDL-C were related with SDNN, and their correlation coefficients were 0.3,0.2,0.665 and 0.681, respectively. ConclusionsHyperlipidemia induced in WZS minipigs by high fat diet may reduce and disturb the autonomic nervous function. The degree of disturbance of autonomic nervous function may be related with duration of hyperlipidemia status, and the risk of dyslipidemia caused by cardiovascular disease is higher in the nighttime than that in daytime. There is a certain dependence between reduced HRV and increased TC, LDL-C, TC/HDL-C and LDL-C/HDL-C ratio. The reduced SDNN can be considered as a predictive indicator of hyperlipidemia independently associated with the risk of development of cardiovascular disease.

Abstract:ObjectiveA mouse model of ethanol consumption was set up. This model was used to investigate the effect of ethanol-exposed on the serum estrogen level and breast cancer progression in mice. Methods2% ethanol in drinking water was given in the ethanol-exposure group mice (n=15) from 8:00 pm to 8:00 am and then replaced with regular water without ethanol at the remaining 12 hours each day for 3 weeks. Mice in the control group (n=15) were provided with regular drinking water only. The water intake, body weight and blood ethanol concentration (BEC) of the mice were checked. The estrogen level in mice serum was quantified by enzyme-linked immunosorbent assay (ELASA). Results The BEC in mice was much higher than that in control mice and similar to drinking humans. No water intake, body weight differences were found in mice with ethanol exposure or without. The serum estrogen level in ethanol drinking group was much higher than that in the control group.ConclusionA mouse alcohol-exposure model has been successfully established. Ethanol consumption might increase the serum estrogen level in mouse.

Abstract:ObjectiveTo explore the impact of intestinal flora changes on the intestinal mucosal immunity. MethodsDenaturing gradient gel electrophoresis (DGGE) was used to study the composition of intestinal flora in three groups of laboratory mice, namely clean mice (CL mice), specific pathogen free mice (SPF mice) and conventional mice (CV mice). Immunohistochemistry (IHC) was used to study the secretion of secretory immunoglobulin A (sIgA) in these three goups of laboratory mice. ResultsThe most numerous diversity of intestinal flora was observed in the CV mice, and the sIgA secretion was also most abundant. There was a significant difference in sIgA secretion from different parts of the intestine (P<0.05), and the distribution of sIgA-positive cells in the small and large intestines was very significantly different (P＜0.01). CL mice were the second one. The intestinal flora between different parts of the intestine was not significantly different, but the distribution of sIgA-positive cells in the small and large intestines was significantly different (P<0.05). There were least strains of bacterial flora in the intestine of SPF mice, and the sIgA secretion was also least, with a non-significant difference in the distribution of sIgA-positive cells between small and large intestines (P>0.05). ConclusionsAlong with the increasing level of animal microorganism control, the diversity of intestinal microbial flora is decreased. The amount of sIgA-positive cells is positively relevant with the intestinal flora diversity. 

Abstract:Objective To study the changes of cerebral hemodynamics revealed by CT perfusion imaging (CTPI) in rabbit models of cerebral microembolism. Methods Thirty normal New Zealand rabbits were randomly divided into two groups:Group A (n =5) underwent sham operation, group B (n =25) underwent an operation of microembolism. About ten SiO₂ grains (D=0.5 mm) were injected into the internal carotid artery from external carotid artery. CTPI was performed continuously at 30 minutes, 3,6, 12, and 24 hours after embolization. At 24 hours after embolism, the rabbits were sacrificed and the brain was removed and prepared for histopathology with HE staining. According to the results of HE staining, the rabbits were divided into cerebral ischemia and cerebral infarction subgroups. The serial changes in cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were discussed respectively. ResultsNo abnormality was seen on both CTPI and HE staining pathology in the group A. In the group B, three rabbits died during the experiment, CTPI was failed in one rabbit because of the failure of femoral vein puncture, and CTPI was succeeded in twenty-one rabbits, including abnormal perfusion in eighteen rabbits and normal perfusion in three rabbits. By HE staining, among the rabbits of abnormal perfusion, ten rabbits were of cerebral infarction, seven rabbits were of cerebral ischemia and one rabbit was normal. At 30 minutes after embolization, the ischemic brain had low perfusion to a different degree, reduced CBF, prolonged MTT and almost normal CBV. During 3 to 6 after embolization, the descended perfusion was further aggravated, the value of CBV was slightly descended. During 12 to 24 hours, the low perfusion was lightened. The cerebral infarction had evidently low perfusion in 30 minutes which showed remarkably descended CBF and CBV, and significantly prolonged MTT. Three rabbits had lightened low perfusion at 3 hours, 6 hours and 12 hours, respectively, but in the subsequent time, the perfusion was descended rapidly again and further aggravated along with time. Another seven rabbits had evidently low perfusion and the degree was aggravated gradually or fluctuated slightly at a certain level. ConclusionsThe cerebral ischemia has most evidently low perfusion during 3 to 6 hours and the low perfusion is lightened during 12 to 24 hours, while the cerebral infarction show that the low perfusion is gradually aggravated along with the time or descended rapidly again after lightened to a different degree. The cerebral ischemia is characterized by mismatch in CBF and CBV values which show a significantly reduced CBF but almost normal CBV, whereas the cerebral infarction shows a matched significant decrease in both CBF and CBV values.

Abstract:Objective To establish an swine influenza virus (H9N2) infection model in BALB/c mice and to provide animal models for studying its pathogenetic mechanism. Methods Eighty mice were divided into experimental and control groups, 40 in each group. The experimental mice were infected with swine influenza virus (H9N2) by nose dropping. Then the clinical symptoms and histopathological and ultrastructural changes were observed. ResultsThe BALB/c mice showed clear clinical symptoms and typical pathological lesions. Conclusion A BALB/c mouse model of swine influenza virus (H9N2) infection has been successfully established.

Abstract:Objective To observe histopathology changes in the main organs of Kunming (KM) mice after intraperitoneally injection of beryllium sulfate (BeSO₄·4H₂O). Methods Thirty 6-week old male KM mice were randomly divided into three groups, administered with saline solution of the beryllium sulfate by intraperitoneally injection every other day for two weeks. The organ coefficients were detected and pathological changes were examined by HE staining. Results Compared with the control group, the organ coefficients of testis, heart, spleen, kidney were not significantly changed, the organ coefficients of lung and liver were changed with significant differences (P<0.05). As for the liver and lung histopathology, it was normal in the control group, but the low dose experimental group presented congestion, hyperemia, bronchiectasic hemorrhage, slight alveolar inflammatory exudates, peribronchitis, interstitial pneumonia and lobular pneumonia. The lung tissue in the high dose experimental group presented bronchiectasic hemorrhage, severe bronchial inflammatory exudates, peribronchial alveolar ectasia, interstitial pneumonia, lobular pneumonia and confluent bronchopneumonia. Swelling of hepatocytes, and spotty and focal necrosis were seen in the liver of mice in the low dose experimental group. The high dose experimental group showed obvious liver damages such as swelling of most hepatocytes and disorganized arrangement of hepatocytes. A strong cytoplasmic vacuolar degeneration, obvious spotty and focal necrosis and inflammatory cell infiltration, acidophilic denaturation of hepatocytes surrounding the necrotic areas, slight pyknotic hepatocyte nuclei, more or less cytoplasmic rarefaction, apparent widening of hepatic sinusoids and central vein with denaturation and necrosis were often observed changes. The testis, heart, spleen and kidney in the model group showed normal histopathological appearance. ConclusionsBeryllium sulfate injected intraperitoneally in the doses used in this study induce apparent damages in the lung and liver tissue of mice, but other organs are not obviously affected.

Abstract:Objective To establish an experimental mouse model of mast cell (MC) migration, and explore the killing mechanism of chemotherapeutic drug As₂O₃ on human esophageal carcinoma EC109 cell line. MethodsMouse mast cell (MC) subsets were defined on the basis of neutral protease composition and immunofluorescence staining, and the distribution image of DNA content in esophageal carcinoma cells was analyzed by propidium iodide labeling and flow cytometry. Secretory granules in MC were observed by laser scanning confocal microscopy. The MC migration from the gut to peritoneal cavity after induction treatments were observed by immunohistochemistry. Results① According to the distribution of flow cytometric dot plot analysis, the mouse MCs were divided into three immunophenotypes:tryptase-positive and chymase-negative MCs (MC T); chymase-positive and tryptase-negative MCs (MC C), and both tryptase-positive and chymase-positive MCs (MC TC). The amount of MC T cells is apparently more than that of MC TC and MC C cells (P<0.05). The laser scanning confocal microscopic observation revealed that all the three subtypes of MCs contained profuse secretory granules distributed in the inner membrane just ready for budding into the extracellular space. ② The mouse MCs migrated from the intestinal tissue into the peritoneal cavity after the induction treatment. The trypsin-induced MC migration was more intensive than that induced by esophageal cancer cells and As₂O₃. ③ The MC migration into peritoneal cavity may be related to cancer cell cycle transition from S phase to G₂/M phase. As₂O₃ could delay esophageal cancer cell cycle in G₀/G₁ phase and impeded cells cycle into S phase, thus inhibiting the growth of esophageal cancer cells. Conclusions The esophageal cancer cells injected into the peritoneal cavity of mice mainly induce T MCs to be involved into immune responses. At the presence of MCs in vivo, the effect of As₂O₃ on tumor cell growth is mainly to delay the cell cycle from G₀/G₁ phase to S phase, or delay the transition from G₂/M phase into cell division.

Abstract:ObjectiveTo analyze the resistin gene homology of humans and some laboratory animals, and provide a basis for the selection of ideal laboratory animals to carry out human disease and gene function studies. Methods To extract total RNA of adipose tissue from macaques, rats, mice and tree shrews. The RT-PCR products were analyzed with bi-directional sequencing. The sequences of resistin gene of human, pig and cattle were inquired in GenBank. Their ORF nucleotide and amino acid sequences were transfered to use the ORF Finder software, and analyzed their sequence homology. ResultsHuman resistin gene of nucleotide sequence homology was 95.4% with macaques, 65.4% with mice, 65.4% with tree shrews, 66.4% with rats, 81.0% with pigs and 81.0% with cattles. The amino acid sequence was 91.7% with macaques, 55.6% with mice, 55.6% with tree shrews, 53.7% with rats, 75.9% with pigs and 72.2% with cattles. The phylogenetic tree results showed a closer relationship between humans and macaques. ConclusionsBased on the resistin gene homology analysis results, it was found that macaques have a closer relationship with humans, and are best laboratory animals in studies of human resistin biological function and related diseases.

Abstract:Objective To study the differences of learning and memory abilities between male and female Tupaia tested by Morris water maze. MethodsNavigation test and probe test were performed to determine the learning and memory abilities in male and female Tupaia. ResultThere were no significant differences in the latency and total distance (P>0.05) between male and female tupaia, but there were significant differences in number of crossing target quadrant and search strategy (P<0.05). ConclusionsThere is no significant difference in navigation test between males and females, but the performance of spatial probe is better in male than in female Tupaia tested by Morris water maze.

Abstract:Objective To study the anti-fatigue effect of Nitraria seed oil in a mouse experiment. Methods Loaded swimming test was used to evaluate the anti-fatigue effect on the mice．Biochemical parameters such as the concentrations of lactic acid and glycogen were determined. ResultsThe swimming time in mice of the Nitraria seed oil group was significantly prolonged, and the serum lactic acid decreased by 40% than those of control mice. Conclusion Nitraria seed oil has some anti-fatigue effects.

Abstract:Recent studies have demonstrated that epigenetic mechanisms may play a pivotal role in the pathogenesis and development of Alzheimer''s disease (AD). Acetylation of histones and non-histone proteins pivotally modulate gene expression and signaling. Histone deacetylase inhibitors are recently suggested to act as neuroprotectors by enhancing synaptic plasticity and learning and memory of AD. HDAC2 is required for neurogenesis. HDAC2 is expressed in the hippocampus suggests a possible role in learning and memory, which negatively regulates learning and memory formation, as well as modulate synaptic plasticity and the number. HDAC2 associates with neurodegenerative impairment. The used HDACIs recently are wide-spectrum drugs, without specificity. Analysis of the HDAC2 unique effects are necessary for the rational design and testing of drug specificity in vivo.

Abstract:Compared with the rodents such as mice, large laboratory animals (i.e., minipigs and monkeys) have more similarities in size, anatomy, physiology, biochemistry, metabolism and disease pathogenesis with humans. Therefore, they may be widely employed and play important roles in replicating human disease models, studying disease pathogenesis and drug discovery, etc. In recent years, lentivirus-mediated gene delivery approach is increasingly used to produce genetically engineered monkeys and minipigs. Compared with pronuclear microinjection and somatic cell nuclear transfer, lentivirus-mediated gene delivery used to generate transgenic animals enjoys the high transgenic efficacy and simple operation. Therefore, it is quite necessary to set up a technology platform for efficiently producing genetically engineered monkeys and minipigs by lentivirus-mediated gene delivery.