神经源性肌萎缩病理动物模型的制备

神经源性肌萎缩常见的原因为废用、营养障碍、缺血和中毒。脊髓前角病变、神经根、神经丛、周围神经的病变等均可引起神经兴奋冲动的传导障碍，从而使部分肌纤维废用，产生废用性肌萎缩。常见的疾病有：脊椎椎骨骨质增生、椎间盘病变、脊神经肿瘤、蛛网膜炎、神经炎、神经丛病变、脊神经肿瘤、神经损伤、脊髓空洞症、运动神经元性疾病、格林一巴利综合征、脑部病变和脊髓病变等。本文试用大鼠坐骨神经双重结扎的方法复制神经源性肌萎缩动物模型。

Anticancer Effect of PS-T on the Experimental Hepatocellular Carcinoma

Objective: To apply PS-T in di?erent phases of carcinoma formation and development, and research the mechanism of anti-carcinoma of PS-T in the cytological level. Methods: N-nitrosodiethylamine (DENA) and CCl4 were applied jointly to duplicate the rat hepatocirrhosis and hepatic cancer model. The rats were divided into 7 groups and were administrated via nasal-stomach tube with PS-T in di?erent phases to interfere the cancer genesis and development. All the rats were killed in 20 weeks for pathological observation. Results: The loss of body weight of rats slowed down in the PS-T-treated group, and the carcinogenesis rate was signi?cantly decreased correspondingly. PS-T could also inhibit the carcinogenesis by supressing the hepatocirrhosis, which showed the positive correlation between the curative e?ect and the curative period. Conclusion: Application of PS-T during cancer induction showed a signi?cant e?ect on preventing and supressing cancer. PS-T might be an ideal drug for clinical anti-cancer therapy. And it will be a main drug in both combined and single treatments for tumor.

Correlation between TIMP-1 expression and liver fibrosis in two rat liver fibrosis models

AIM： To evaluate serum TIMP-1 level and the correlation between TIMP-1 expression and liver fibrosis in immuneinduced and CCL4-induced liver fibrosis models in rats. METHODS： Immune-induced and CCL4-induced liver fibrosis models were established by dexamethasone （0.01 mg） and CCL4 respectively. Serum TIMP-1 level was detected with ELISA, while histopathological grade of liver biopsy was evaluated. Spearman rankcorrelation test was used to analyse the difference of the correlation between the TIMP-1 expression and hepatic fibrosis in the two fibrosis models. Furthermore,in situ hybridization was used to determine the expression difference of TIMP-1 mRNA in the two models. RESULTS： Positive correlation existed between serum TIMP-1 level of immune induced group and the histopathological stages of fibrosis liver of corresponding rats （Spearman rank-correlation test, rs = 0.812, P 0.05）, and the positive in situ hybridization signal of TIMP-1 mRNA was strong. In CCL4-induced liver fibrosis model, the correlation between the serum TIMP-1 level and the severity of hepatic fibrosis was not statistically significant（Spearman rank-correlation test, rs = 0.229, P 〉 0.05）. And compared with immune-induced model, the positivein situ hybridization signal of TIMP-1 mRNA was weaker, while the expression variation was higher in hepatic fibrosis of the same severity. CONCLUSION： The correlations between TIMP-1 expression and liver fibrosis in two rat liver fibrosis models are different. In immune-induced model, serum TIMP-1 level could reflect the severity of liver fibrosis, while in CCL4-induced model, the correlation between the serum TIMP-1 level and the severity of hepatic fibrosis was not statistically significant.

New animal models for hepatitis C viral infection and pathogenesis studies

Hepatitis C virus （HCV） is a major cause of chronic liver disease, cirrhosis and hepatocellular carcinoma （HCC）. In man, the pathobiological changes associated with HCV infection have been attributed to both the immune system and direct viral cytopathic effects. Until now, the lack of simple culture systems to infect and propagate the virus has hampered progress in understanding the viral life cycle and pathogenesis of HCV infection, including the molecular mechanisms implicated in HCV-induced HCC. This clearly demonstrates the need to develop small animal models for the study of HCV-associated pathogenesis. This review describes and discusses the development of new HCV animal models to study viral infection and investigate the direct effects of viral protein expression on liver disease.

Generation and characterization of a transgenic mouse model for pancreatic cancer

AIM： To generate a SV40Tag transgenic tumor animal model and to study the mechanism underlying tumorigenesis. METHODS： A mammary gland expression vector containing SV40Tag DNA was generated. Transgene fragments were microinjeted into fertilized eggs of FVB mice. The genetically manipulated embryos were transferred into the oviducts of pseudo-pregnant female mice. PCR and Northern blot analysis were used for genotype analysis of F1 and F2 mice. Transgene expression was detected by RT-PCR and immunohistochemistry. RESULTS： SV40Tag gene was detected in two lines of transgenic mice. One of them delivered the transgene to F1 and a tumor was found in the pancreas of these mice. RT-PCR and immunohistochemistry showed that SV40Tag gene was expressed in the tumor. Pathological characterization of the transgenic mice demonstrated that the tumor belonged to pancreatic cystic neoplasm. CONCLUSION： SV40Tag transgenic mouse model can be successfully established. The transgenic mice develop a pancreatic tumor, which can be used for investigation of the molecular mechanism of tumorigenesis in vivo.

Animal models of portal hypertension

Animal models have allowed detailed study of hemodynamic alterations typical of portal hypertension and the molecular mechanisms involved in abnormalities in splanchnic and systemic circulation associated with this syndrome. Models of prehepatic portal hypertension can be used to study alterations in the splanchnic circulation and the pathophysiology of the hyperdynamic circulation. Models of cirrhosis allow study of the alterations in intrahepatic microcirculation that lead to increased resistance to portal flow. This review summarizes the currently available literature on animal models of portal hypertension and analyzes their relative utility. The criteria for choosing a particular model, depending on the specific objectives of the study, are also discussed.

Smad3 knock-out mice as a useful model to study intestinal fibrogenesis

AIM： To evaluate the possible differences in morphology and immunohistochemical expression of CD3, transforming growth factor 131（TGF-131）, Smad7, α-smooth muscle actin （α-Sma）, and collagen types Ⅰ-Ⅶ of small and large intestine in Smad3 null and wild-type mice. METHODS： Ten null and ten wild-type adult mice were sacrificed at 4 mo of age and the organs （esophagus, small and large bowel, ureters） were collected for histology（hematoxylin and eosin, Masson thrichrome, silver staining）, morphometry and immunohistochemistry analysis. TGF-β1 levels of intestinal tissue homogenates were assessed by ELISA. RESULTS： No macroscopic intestinal lesions were detected both in null and wild-type mice. Histological and morphometric evaluation revealed a significant reduction in muscle layer thickness of small and large intestine in null mice as compared to wild-type mice. Immunohistochemistry evaluation showed a significant increase of CD3＋T cell, TGF-β1 and Smad7 staining in the small and large intestine mucosa of Smad3 null mice as compared to wild-type mice. α-Sma and collagen Ⅰ-Ⅶ staining of small and large intestine did not differ between the two groups of mice. TGF-β1 levels of colonic tissue homogenates were significantly higher in null mice than in wildtype mice. In preliminary experiments a significant reduction of TNBS-induced intestinal fibrosis was observed in null mice as compared to wild-type mice.

A simple and sensitive method to assess ischemia occurrence in the setting of focal cerebral ischemia in rat: A comparative study

Objective: Neurological evaluation is commonly applied to identify ischemia in focal cerebral ischemia model though it might not be sensitive. In present study, we hired sleeping time to assess ischemia occurrence. Methods: Permanent middle cerebral artery occlusion was induced in Sprague-Dawley rats under pentobarbital and ketamine anesthesia respectively. Sleeping time was recorded. Neurological evaluation was conducted by modified Bederson’s scoring system at 4 h and histopathological evaluation was performed at 3 d after middle cerebral artery occlusion. Results: Slices of brain stained by TTC, H&E and hoechst 33258 revealed extensive lesion in the two ischemic groups. The sensitivity to identify ischemia by neurological evaluation was 62.5%, but it was 81.3% and 80% respectively when evaluating by sleeping time (pentobarbital: ≥90.7 min, ketamine: ≥36.1 min). The sensitivity to identify ischemia by sleeping time was significantly higher than that by neurological evaluation (P<0.05). Conclusion: Our results suggested that to identify ischemia by sleeping time is a simple and sensitive method in the setting of focal cerebral ischemia in rat.

Basal physiological parameters in domesticated tree shrews (Tupaia belangeri chinensis)

Establishing non-human primate models of human diseases is an efficient way to narrow the large gap between basic studies and translational medicine. Multifold advantages such as simplicity of breeding, low cost of feeding and facility of operating make the tree shrew an ideal non-human primate model proxy. Additional features like vulnerability to stress and spontaneous diabetic characteristics also indicate that the tree shrew could be a potential new animal model of human diseases. However, basal physiological indexes of tree shrew, especially those related to human disease, have not been systematically reported. Accordingly, we established important basal physiological indexes of domesticated tree shrews including several factors: (1) body weight, (2) core body temperature and rhythm, (3) diet metabolism, (4) locomotor rhythm, (5) electroencephalogram, (6) glycometabolism and (7) serum and urinary hormone level and urinary cortisol rhythm. We compared the physiological parameters of domesticated tree shrew with that of rats and macaques. Results showed that (a) the core body temperature of the tree shrew was 39.59±0.05 °C, which was higher than that of rats and macaques; (b) Compared with wild tree shrews, with two activity peaks, domesticated tree shrews had only one activity peak from 17:30 to 19:30; (c) Compared with rats, tree shrews had poor carbohydrate metabolism ability; and (d) Urinary cortisol rhythm indicated there were two peaks at 8:00 and 17:00 in domesticated tree shrews, which matched activity peaks in wild tree shrews. These results provided basal physiological indexes for domesticated tree shrews and laid an important foundation for diabetes and stress-related disease models established on tree shrews.

Systematic review of robust experimental models of rheumatoid arthritis for basic research

Rheumatoid arthritis(RA)is a common autoimmune disease characterized by progressive joint inflammation and destruction,deformity,loss of mobility,and permanent disability.Although the cellular and molecular mechanisms involved in RA are understood in detail,no drugs or therapies can completely cure RA.Many long-term efforts have been directed towards a better understanding of RA pathogenesis and the development of new classes of therapeutics.Thus,the ongoing elucidation of pathogenic events underlying RA mostly relies on studies of animal models.Herein,we comprehensively review and discuss the characteristics,challenges,and unresolved of issues of various experimental models of RA to provide a basis and reference for the rational selection of experimental RA models for basic investigations into traditional Chinese medicine(TCM).

THE PATHOGENESIS OF EXPERIMENTAL MODEL OF MITOCHONDRIAL MYOPATHY INDUCED BY GERMANIUM DIOXIDE

Objective. The purpose of the study was to build up an animal model of mitochondrial myopathy in order to analyse the pathogenesis of the disease. Methods. The skeletal muscles from Wistar rats treated with germanium dioxide for 24 weeks were analysed by histopathologic and electron- microscopic studies. A quantitative analysis was carried out in mitochondrial DNAs of these samples. The biological function of the model was determined. Results. An animal model of mitochondrial myopathy was built up, in which oxygen free radicals were increased and mitochondrial DNA copies were decreased contrasted with controls. Conclusion. It suggested that environmental toxin may play a role in the pathogenesis of mitochondrial myopathy. The increase of oxygen free radicals is an important link causing the disease.

Study of a Novel Small Caliber Vascular Graft in a Canine Model with Optical and Scanning Electron Microscopy

A novel biological small-diameter vascular graft was evaluated in a canine model. 3 cm long segments with 4 mm I.D. were implanted end-to-end in the carotid position of 12 dogs for 6 months. Color Doppler sonography was performed at the first week post-operation, and angiography was then administered to 9 grafts at 4th week, 12th week and 24th week respectively to monitor the graft pantency and blood flow characteristics. Vascular samples containing the grafts were collected at 1st week, 8th week, 12th week and 24th week after implantation. Morphological changes of the grafts were observed by optical and scanning electron microscopic (SEM) studies and compared with that of the original prosthesis and the normal host vessel. All grafts were patent throughout the experiment except one graft. Histopathology and SEM demonstrated both a nearly complete inner capsule of varied thickness lining the graft luminal surface and connective tissue adventitia formation at one-week post-operation. The neointima became confluent at 8 weeks and then compact but had no signs of hyperplasia up to 12 weeks; meanwhile on the neointimal surface newly grown endothelial-like cells were migrating from the stoma to the middle portion. The grafts also illustrated endothelialization in many “islands” in the mid-segment luminal surface of the grafts. In addition, the closer distance the cells towards the stoma were, the more morphological similarity the cells with the normal endothelial were. Taken together, the biological vascular graft remained patent for 24 weeks as a carotid prosthesis, characterized by the early and complete neointima formation plus endothelialization starting before 12 weeks post grafting. Therefore, the graft seems suitable for reconstruction of vascular lesions in dogs. Further studies may be carried out to extend the graft application for the clinical use.

PATHOLOGICAL AND MORPHOLOGICAL RESEARCH OF EXPERIMENTAL ACETABULAR DYSPLASIA

Objective To investigate the pathological mechanism of hip dysplasia. Methods The leftknee joints of eighteen rabbits were fixed in extending position with plaster cylinder for four weeks, but their hip joints were flexed. The right side served as control. Roentgenogram was made in all animals. The changes of the x-ray films and the pathological findings between left and right hips were compared. Results Appearance of hip dysplasia was obvious at four weeks after plaster fixation. There were pathological changes, including shallow ace-tabulum and flat femoral head, increased acetabular index and decreased acetabular head index on the x-ray films. Conclusion The hip dysplasia is the result of prolonged extending position of the knee joint. Abnormal knee posture seems to be one of the important factors of hip dysplasia. This kind of deformation may be worsened with time.

STUDY ON INFLAMMATORY CELLS IN BALF OF SMOKE-INDUCED CHRONIC BRONCHITIS RAT MODEL

Objective To establish a smoke-induced chronic bronchitis rat model and evaluate the patho-logical change semi-quantitatively, and study the characteristics of the inflammatory cells in the bronchoalveolar lav-age fluid (BALF) in various stages. Methods Chronic bronchitis sequential rat model was established by passively inhaling smoke mixture. Experiments were performed in 30 young male Sprague-Dawley rats, which comprised 5 groups in random, i.e.,4 chronic bronchitis model groups and 1 control group. After stained with hematoxylin and eosin, the specimens were studied by semi-quantitative method to evaluate the morphologic changes in various stages. Meanwhile, the inflammatory cells of the BALF and the activity of myeloperoxidase (MPO) of lung tissue were analysed. Results During the process of the chronic bronchitis, the pathologic score was increasing as time went on, and the typical morphologic changes of chronic bronchitis emerged in the group 7 weeks. The total number of inflammatory cells in BALF was increasing as time went on, correlated with the pathologic scores (P <0.01). And the percentage of lymphocyte increased as well as positively correlated with pathologic scores (P < 0. 05) , whereas that of macrophage decreased and negatively correlated with pathologic scores (P <0. 05). The MPO lever of lung tissue was correlated with the pathologic scores (P < 0. 01). But the percentage of the neutrophil in the BALF was just in a high level during the first week, then it maintained relatively lower. Conclusion Smoke-induced chronic bronchitis is a slowly progressive inflammation process. The model we established is convenient and simple for the longitudinal study on the inflammatory process of chronic bronchitis and the therapy in the early stage. The semi-quantitative evaluation for the pathological change is with much more value. During the inflammatory sequential process of early stage of chronic bronchitis, the cellular characteristics are similar to that of the common chronic inflammation.

解脲脲原体对新生小鼠的致病作用和发病机理研究

为探讨解脲脲原体（Ｕｕ）对新生小鼠的致病作用和致病机理，应用常规病理、免疫组化和电镜等技术观察了１～１４型Ｕｕ株对不同日龄小鼠肺的致病作用。结果表明，各型Ｕｕ均可引起新生小鼠急性自限性的间质性肺炎，对１４日龄小鼠则较少引起感染；感染后的小鼠症状较轻；在有病灶的肺组织中可再培养出Ｕｕ；部分１４日龄小鼠产生对Ｕｕ的特异ＩｇＭ抗体；免疫组化显示在支气管壁及肺泡间隔处有Ｕｕ抗原；电镜显示，在纤毛细胞间、肺间质中有Ｕｕ的存在。结果提示，Ｕｕ可能是通过吸附纤毛细胞，然后经细胞之间连接和支气管上皮细胞之间，沿支气管向肺泡扩散，引起肺部间质性炎症。Ｕｕ肺炎的发生与小鼠年龄及免疫状态有关。

Effect of puerarin on neural function and histopathological damages after transient spinal cord ischemia in rabbits

Objective: To investigate the effect of puerarin on the neural function and the histopathological changes after ischemic spinal cord injury in rabbits. Methods: Thirty male New Zealand white rabbits were randomly divided into three groups as follows: puerarin group (n=10) receiving intravenous infusion of 30 mg/kg puerarin for 10 minutes, control group (n=10) receiving intravenous infusion of the same volume of normal saline as puerarin for 10 minutes, and sham operation group (n=10) undergoing only the surgical exposure of the abdominal aorta. Temporary spinal cord ischemia was induced by infrarenal aortic occlusion for 20 minutes and followed by reperfusion. The neural status was scored with the Tarlov criteria at 8, 12, 24 and 48 hours after reperfusion. All the animals were killed at 48 hours after reperfusion and the spinal cords (L 5) were removed immediately for histopathological study. Results: The neural function scores at 8, 12, 24 and 48 hours after reperfusion were higher in the puerarin group and sham operation group than those in the control group (P< 0.05). More normal motor neurons in the anterior horn of spinal cord were present in the puerarin group and sham operation group than those in the control group (P< 0.01). There was a strong correlation between the final neural function scores and the number of normal motor neurons in the anterior horn of spinal cord (r= 0.839, P< 0.01). Conclusions: Puerarin can significantly ameliorate the neural function and the histopathological damages after transient spinal cord ischemia in rabbits.

Changes of proton transportation across the inner mitochondrial membrane and H^+-ATPase in endotoxic shock rats

Objective: To investigate the changes of proton transportation across the inner mitochondrial membrane (IMM) and H + ATPase of hepatocytes in endotoxic shock rats. Methods: Endotoxin from E.Coil of 5.0 mg/kg or saline of 1 ml/kg was injected into the femoral vein. The rats were sacrificed pre injection and 1, 3, 5, 8 hours after injection, and plasma and liver tissue samples were collected respectively. The liver tissue samples were used for preparation of mitochondria and submitochondrial particles (SMPs). The proton translocation of SMPs and H + ATPase, phospholipase A 2 (PLA 2) activities and malondialdehyde (MDA) content, membrane fluidities of different level of mitochondria membrane and plasma MDA content were assayed. Results: (1) Five hours after E. Coli. O111B4 injection, the maximum fluorescence quenching ACMA after adding ATP, nicotinamide adenin dinucleoacid hydrogen (NADH), and the succinate were significantly decreased (P< 0.05 ). The time of maximum fluorescent quenching and the half time of fluorescent quenching were significantly prolonged (P< 0.01 ), especially when NADH was used as a substrate. (2) The mitochondrial H + ATPase activity was significantly increased at early stage of endotoxic shock (P< 0.05 ), and significantly decreased at late stage of endotoxic shock (P< 0.01 ). (3) The mitochondrial membrane bound PLA 2 activity, plasmal and mitochondrial MDA content were significantly increased and succinate dehydrogenase (SDH) activity of mitochondria decreased markedly in endotoxic shock rats (P< 0.05 ). (4) The mitochondrial membrane fluidity of different lipid regions was decreased, especially in the head of phospholipid. Conclusions: Proton transportation across IMM and mitochondrial H + ATPase activity are significantly decreased in endotoxic shock.