Neonatal rhesus monkeys as an animal model for rotavirus infection

AIM To establish a rotavirus(RV)-induced diarrhea model using RV SA11 in neonatal rhesus monkeys for the study of the pathogenic and immune mechanisms of RV infection and evaluation of candidate vaccines.METHODS Neonatal rhesus monkeys with an average age of 15-20 d and an average weight of 500 g ± 150 g received intragastric administration of varying doses of SA11 RV( 107 PFUs/mL, 106 PFUs/mL, or 105 PFUs/mL, 10 mL/animal) to determine whether the SA11 strain can effectively infect these animals by observing their clinical symptoms, fecal shedding of virus antigen by ELISA, distribution of RV antigen in the organs by immunofluorescence, variations of viral RNA load in the organs by qRT-PCR, histopathological changes in the small intestine by HE staining, and apoptosis of small intestinal epithelial cells by TUNEL assay.RESULTS The RV monkey model showed typical clinical diarrhea symptoms in the 108 PFUs SA11 group, where we observed diarrhea 1-4 d post infection(dpi) and viral antigen shed in the feces from 1-7 dpi. RV was found in jejunal epithelial cells. We observed a viral load of approximately 5.85 × 103 copies per 100 mg in the jejunum at 2 dpi, which was increased to 1.09 × 105 copies per 100 mg at 3 dpi. A relatively high viral load was also seen in mesenteric lymph nodes at 2 dpi and 3 dpi. The following histopathological changes were observed in the small intestine following intragastric administration of SA11 RV: vacuolization, edema, and atrophy. Apoptosis in the jejunal villus epithelium was also detectable at 3 dpi.CONCLUSION Our results indicate that we have successfully established a RV SA11 strain diarrhea model in neonatal rhesus monkeys. Future studies will elucidate the mechanisms underlying the pathogenesis of RV infection, and we will use the model to evaluate the protective effect of candidate vaccines.     

斑马鱼疾病模型

斑马鱼基因组与人类基因组具有高度同源性,作为一种新型的实验动物,已在相关生物研究中广泛应用,用斑马鱼复制的疾病模型在人类疾病研究中起重要作用。本文就斑马鱼在骨骼、心脏、神经系统和肿瘤等方面研究中的作用进行综述。     

尿素酶疫苗在防治幽门螺杆菌感染的动物实验研究

目的利用人类幽门螺杆菌（Ｈｐ）感染的小鼠模型研究Ｈｐ粗抗原及纯化尿素酶在预防与治疗Ｈｐ感染的作用。方法超声粉碎制备Ｈｐ全菌抗原,化学提纯制备Ｈｐ尿素酶,霍乱毒素（ＣＴ）为免疫佐剂。实验分为预防与治疗两部分。预防部分把实验动物无特定致病菌（Ｓ．Ｐ．Ｆ．）ＢＡＬＢ／ｃ小白鼠分成５组,分别通过灌胃方法给予尿素酶（２５０μｇ）加ＣＴ（２μｇ）、Ｈｐ粗抗原（１ｍｇ）加ＣＴ（２μｇ）、生理盐水、单纯尿素酶（２５０μｇ）、单纯ＣＴ（２μｇ）,每周１次,共４次。２周后再用活Ｈｐ灌胃,再４周后处死动物。治疗部分把已感染Ｈｐ的小白鼠分成５组,分组与治疗方法同预防部分,治疗结束后４周处死动物,取胃粘膜行尿素酶试验与改良Ｇｉｅｍｓａ染色检查Ｈｐ情况。结果预防实验的保护率分别为,尿素酶加ＣＴ７０％（７／１０）,Ｈｐ粗抗原＋ＣＴ８０％（８／１０）,生理盐水、单纯尿素酶、单纯ＣＴ保护率均为０。治疗实验各组Ｈｐ根除率分别为：尿素酶加ＣＴ６３．６％（７／１１）,Ｈｐ粗抗原加ＣＴ４４．４％（４／９）,生理盐水组、单纯尿素酶、单纯ＣＴ组均无治疗作用。结论由尿素酶加免疫佐剂组成的口服疫苗,不仅有预防Ｈｐ感染的作用,同时也有根除已感染的Ｈｐ的作用。     

The woodchuck as an animal model for pathogenesis and therapy of chronic hepatitis B virus infection

INTRODUCTION Infection of adult humans with the hepatitis B virus (HBV) results characteristically in self-limited hepatic disease with recovery based on serological and clinical parameters. Progression to chronic HBV infection occurs infrequently in infe…     

长爪沙鼠作为牛带绦虫终末宿主实验动物的初步研究

目的 利用长爪沙鼠作为牛带绦虫终末宿主实验动物模型的探索。方法 将牛带绦虫虫卵用酶法孵化后经皮下注射感染免疫抑制小鼠，不同时期获取的活囊尾蚴分别经灌胃感染沙鼠，同时皮下注射地塞米松1～2mg／d进行免疫抑制。感染后1～62d剖杀沙鼠，观察沙鼠的感染情况，从小肠检获的虫体经整体染色或作常规切片HE染色。观察其外部形态及内部结构。结果 8只沙鼠被感染，分别在感染后1，2，3，10，30d从沙鼠小肠内检获4，4，4，6，1条虫体，其中11条完整虫体的长度为10．56（1．0～45．5）mm。感染后10，30d虫体分节，但节片较幼稚，未见原始生殖细胞和发育成熟的生殖器官。结论 小鼠体内获取的囊尾蚴可以在免疫抑制的长爪沙鼠小肠内生长发育一段时间，但未发育成熟。     

Examination of the utility of the rat as an animal model for human anticoagulation

The feasibility of employing the rat as an experimental model for investigation of full-dose heparin anticoagulation was assessed. Striking similarities were found to exist between rats and humans regarding baseline-activated partial thromboplastin time (APTT) values, and dosage per kilogram of heparin required to produce an APTT value of 1 1/2-3 times normal, the clinical definition of full-dose heparinization. Based upon these similarities, it appears that the rat can effectively serve as an experimental model for investigating the effects of heparin in humans.     

NOD-scid mouse as an experimental animal model for cysticercosis

The major three species of human taeniid cestodes, Taenia solium, T. saginata and T. saginata asiatica (= T. asiatica) which require humans as the definitive host are still not rare in developing countries. Among these, T. solium is the most serious with medical and economic importance. Neurocysticercosis (NCC) in humans is now recognized as the major cause of neurologic disease in the world. As these human taeniid cestodes obligatory require domestic animals such as swine, cattle and swine as the major intermediate host animals respectively, it is not easy to analyze the basic research in these domestic animals. In this brief review, we introduce experimental animal model for these three species in order to obtain fully developed metacestode stage in severe combined immunodeficiency (scid) mice. Non-obese diabetic scid (NOD-scid) mice are expected to be a satisfactory animal model and to have advantages for analysis by several view points of developmental biology with gene expression throughout development, antigenic homology of cyst fluid of these three species, evaluation of drug efficacy or metacestocidal drug designs, confirmation of unknown taeniid gravid segments for identification based on the morphology and DNA analysis of metacestodes. The animal model is not only available for human Taenia spp but can also be applied to other taeniid cestodes of economic importance or in veterinary parasitology.     

The potential for vaccine development against chlamydial infection and disease

Chlamydia trachomatis and Chlamydia pneumoniae appear to share a common immunobiology with about 80% of their protein coding genes being orthologs. Progress in DNA vaccine development for C. trachomatis suggests that such a subunit approach may prove useful for C. pneumoniae. The recent finding that it is possible to select for chlamydiae with targeted mutations in key metabolic genes together with the new knowledge of the chlamydia genome also suggests that it may be possible to develop live attenuated strains of chlamydiae for use as vaccine.     

Antipsychotic drug-induced weight gain: development of an animal model

OBJECTIVE: Weight gain is a prominent effect of most atypical antipsychotic drugs (AAPDs); yet, the mechanisms are not fully understood and no well-established mouse models exist for investigating the mechanisms. Thus, we developed a mouse model to evaluate the effects of AAPDs on eating, body weight (BW), and body composition. METHODS: Female C57BL/6J mice were used to test olanzapine, quetiapine, ziprasidone, and risperidone. Mice were acclimated to individual housing, given ad libitum access to chow and water, dosed with placebo peanut butter pills for 1 week, and then dosed daily with AAPD-laced peanut butter pills for 4 weeks. Weekly food intakes and BWs were measured, and body compositions were determined at the end of each experiment. RESULTS: After 4 weeks of treatment, olanzapine, quetiapine, ziprasidone, and risperidone caused significant weight increases, but only olanzapine and quetiapine were associated with significantly increased food intake. Body composition data revealed that olanzapine-treated mice had more relative fat mass and risperidone-treated mice had more relative lean mass than did control mice. Quetiapine and ziprasidone did not significantly affect relative body composition even though BW was increased. CONCLUSIONS: Oral AAPD administration causes increased BW in female mice. Our mouse model of AAPD-induced weight gain resembles the human response to these medications and will be used to investigate the mechanisms for weight gain and fat accumulation.     

Antigen selection based on expression levels during infection facilitates vaccine development for an intracellular pathogen

Vaccines effective against intracellular pathogens could save the lives of millions of people every year, but vaccine development has been hampered by the slow largely empirical search for protective antigens. In vivo highly expressed antigens might represent a small attractive antigen subset that could be rapidly evaluated, but experimental evidence supporting this rationale, as well as practical strategies for its application, is largely lacking because of technical difficulties. Here, we used Salmonella strains expressing differential amounts of a fluorescent model antigen during infection to show that, in a mouse typhoid fever model, CD4 T cells preferentially recognize abundant Salmonella antigens. To identify a large number of natural Salmonella antigens with high expression levels during infection, we used a quantitative in vivo screening strategy. Immunization studies with five particularly attractive candidates revealed two highly protective antigens that might permit the development of an improved typhoid fever vaccine. In conclusion, we have established a rationale and an experimental strategy that will substantially facilitate vaccine development for Salmonella and possibly other intracellular pathogens.     

Somatic gene transfer in the development of an animal model for primary hyperparathyroidism.

The overproduction of hormones is associated with a variety of endocrinological disorders. We have used somatic cell gene transfer of human PTH (hPTH) to develop an animal model of hypercalcemia and osteoclastic skeletal resorption. Recombinant retroviruses were used to transduce a functional hPTH gene into cultured rat fibroblasts. The recombinant-derived preproparathyroid hormone peptide was appropriately processed in this ectopic cell, and intact hPTH (1-84) was secreted at a high level (2-5 ng/10(6) cells/24 h). Transplantation of the PTH-secreting cells into syngeneic rat recipients was associated with the development of hypercalcemia mediated by increasing serum concentrations of hPTH. Thyroparathyroidectomy in these hypercalcemic rats producing hPTH did not result in hypocalcemia and tetany, which was observed in control animals undergoing thyroparathyroidectomy. Chronic overproduction of hPTH (60 days) was associated with severe hypercalcemia, metastatic calcification, and histological changes of osteoclastic resorption of bone. This animal model will be useful in studying the pathophysiology of severe hyperparathyroidism in humans and should help in the evaluation of new medical therapies for hypercalcemia.     

Cattle as a model for development of vaccines against human tuberculosis

The identification of tuberculosis vaccines and vaccination strategies, which in small animal models appear to be more effective than BCG, offer some exciting possibilities for control of human tuberculosis in the future. However, some major problems remain including selecting which vaccines should go into human trials and the length of time it will take for testing these vaccines in humans. The cattle model is well suited for the secondary screening of tuberculosis vaccines as there is a strong similarity between the disease in cattle and humans and outbred animals are used. Moreover, there are many similarities in the results from field trials of BCG in both cattle and humans, with BCG often failing to protect when the trials are extended over a number of years. In addition, calves, like human infants, are immunocompetent at birth. Recent studies in calves have shown that BCG vaccination of calves within hours of birth is highly effective in protecting animals against bovine tuberculosis, but BCG revaccination at 6 weeks of age is contraindicated. Prime boost vaccination strategies using BCG and DNA vaccines have provided evidence that these combinations may give better protection in calves than either vaccine alone. Based on antigens whose genes are absent from the BCG genome, advances have also been made to develop diagnostic reagents distinguishing infected and vaccinated animals (differential diagnosis). The cattle model has been particularly useful in prioritizing such antigens for testing in humans. Finally, there is an urgent need to identify an immunological correlate of protection against tuberculosis. The cattle model can be particularly helpful in this area as it is relatively easy to collect large volumes of blood from calves at intervals following vaccination and challenge, and a large number of immunological reagents are now available for cattle.     

Simple animal model of Helicobacter pylori infection

Helicobacter pylori(H.pylori)has become accepted as a human pathogen for the development of gastritis and gastroduodenal ulcer.To develop a simple rat model of chronic H.pylori infection,male Sprague-Dawley rats were pretreated with streptomycin suspended in tap water(5 mg/mL)for 3 d.The rats were inoculated by gavage at 1 mL/rat with H.pylori suspension(5×108-5×1010 CFU/mL)twice daily at an interval of 4 h for three consecutive days.Two weeks after inoculation,rats were sacrificed and the stomachs were removed.Antral biopsies were performed for urease test and the stomachs were taken for histopathology.Successful H.pylori inoculation was defined as a positive urease test and histopathology.We reported a 69.8%-83.0%success rate for H.pylori infection using the urease test,and hematoxylin and eosin staining confirmed the results.Histopathological analysis detected bacteria along the mucous lining of the surface epithelium and crypt lumen and demonstrated mild to moderate gastric inflammation in successfully inoculated rats.We developed a simple rat model of chronic H.pylori infection for research into gastric microcirculatory changes and therapy with plant products.     

幽门螺杆菌中性粒细胞激活蛋白C-末端区域疫苗治疗小鼠幽门螺杆菌感染

目的在人类幽门螺杆菌(Hp)感染的C57BL/6小鼠模型中,研究中性粒细胞激活蛋白C-末端区域疫苗治疗Hp感染的作用。方法把已感染Hp的C57BL/6小鼠分成4组,分别通过灌胃法给予单纯中性粒细胞激活蛋白C-末端蛋白(100μg)、中性粒细胞激活蛋白C-末端蛋白(100μg)加霍乱毒素(CT,2μg)、单纯CT(2μg)或PBS,每周1次,共4次,治疗4周后处死动物,取胃黏膜行半定量细菌培养检查Hp情况。结果治疗后各组Hp根除率分别为:中性粒细胞激活蛋白C-末端蛋白加CT组50%(5/10),单纯中性粒细胞激活蛋白C-末端蛋白组、单纯CT组及PBS组根除率均为0%。统计分析表明中性粒细胞激活蛋白C-末端蛋白加CT组的H.pylori根除率较其它组有显著性差异(P0.05)。此外,未根除Hp的小鼠,中性粒细胞激活蛋白C-末端蛋白加CT组Hp的定植密度明显低于其它3组(P0.05)。结论中性粒细胞激活蛋白C-末端蛋白能够作为Hp多价治疗疫苗的组分之一。     

Neuroendocrine peptides in stomach and colon of an animal model for human diabetes type I.

Twelve prediabetic and 12 diabetic non-obese diabetic (NOD) mice, all females aged 22-24 weeks, were investigated. As controls, 12 BLAB/cJ Bom mice of the same age and gender as the NOD mice were used. The concentration of several neuroendocrine peptides was determined by radioimmunoassay of tissue extracts of transmural specimens of antrum and distal colon. The neuroendocrine peptides investigated were peptide YY (PYY), somatostatin, vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), neurotensin, and galanin. In the antrum, VIP, NPY, and galanin concentrations were all significantly lower in prediabetic and diabetic NOD mice than in controls. There was no statistical difference between NOD mice and controls regarding neurotensin content. In the colon, the concentrations of PYY, somatostatin, VIP, NPY, and galanin were lower in prediabetic and diabetic NOD mice than in controls. The concentration of neurotensin in prediabetic, but not in diabetic NOD mice was lower than that of controls. The present observations support the previously reported studies on animal models for human type I diabetes that the neuroendocrine system of the gut is disturbed. It also shows that the neuroendocrine system of the stomach and large intestine is affected. The present findings may have some implications for the gastrointestinal dysfunction observed in patients with human type I diabetes.