不同等级环境对大、小鼠及其应用的影响

目的了解不同等级环境（屏障环境和普通环境）对实验大小鼠的一般生理表现和抗应激能力以及对药物反应的影响,初步判定严格的微生物控制是否影响实验动物的人类模型作用。方法将40只SPF级Wistar大鼠和200只SPF级BALB／c小鼠分别饲养于屏障环境和普通环境内,通过以下实验对比观察不同等级环境对实验大、小鼠及其应用的影响：每周测量动物的体重增长情况;饲养35d后,测定大鼠15项血液学指标、14项血液生化指标和9个脏器的相对重量;以抗缺氧实验和游泳实验判断对小鼠体质和抗应激能力的影响;以5．氟尿嘧啶急性毒性实验和戊巴比妥钠麻醉实验测试其对药物作用的异同。结果在5周观察期内,屏障环境饲养小鼠和大鼠的体重增长均明显快于普通环境的对照动物（P〈0．05）;普通环境饲养大鼠的血液RBC、WBC、PCT、PLT、GOT、GGT、GPT、CK、TB值高于屏障环境大鼠（P〈0．05）,而CHO、LDL-C和HDL-C值低于屏障环境大鼠（P〈0．05）;不同微生物环境条件饲养小鼠的游泳耐力和抗缺氧实验结果接近,但是屏障环境组动物所获数据的变异较小;不同等级环境条件饲养小鼠的戊巴比妥钠麻醉反应和5-氟尿嘧啶中毒反应相似,而屏障环境组动物的麻醉维持时间较短,LD50较低,95％可信限狭窄。结论饲养于屏障环境和普通环境的实验大、小鼠在一般生理表现上出现部分差异,动物的抗应激能力和对药物的反应未发生显著变化;在屏障环境条件中,动物的药物反应更敏感、所获数据更稳定,因此,初步认为严格微生物控制条件下的SPF级动物可以作为生活在自然环境中的人类的模型动物。     

摘要

实验动物环境丰富 环境丰富又称环境丰容（environmental enrichment）,是指对圈养动物所处的物理环境进行修饰,改善环境质量,提高其生物学功能,如生殖成功率和适应性等,从而提高其福利水平。环境丰富这一概念最早在1925年被提出和应用。环境丰富化最主要的精神,就是不要让动物觉得无聊,让动物满足本能需求,包括觅食、筑巢、 寻找隐蔽物体等的本能。丰富化的环境可使动物表现正常生理,防止动物产生异常的行为与不正常的身心发展,避免内分泌或免疫系统异常常。虽然采用环境丰富技术会使得实验动物的生存状态改善,但是环境丰富度的增加,会增加实验结果的变异。总的来说,实验动物环境丰富研究领域仍然存在很多未知的问题。     

昆明种小鼠体长与尾长的测定

昆明种小鼠是我国目前使用最广泛的实验动物,为了解其年龄与体长,尾长的关系,我们选用不同日龄的封闭群昆明种小鼠,对其体长、尾长分别进行测定,现将结果报告如下。 (一)材料与方法 1.动物来源 (1)选取某动物室昆明种饲养间生产群全部经产小鼠,作为种鼠组。将在育种中注意挑选体壮、尾粗长的经产种鼠作为A群鼠,忽视挑选尾长的经产种鼠作为B群鼠。 (2)随机选用不同日龄的昆明种小鼠。 (3)随机选用父母亲是尾长/体长值大于1的三窝仔鼠中的雌鼠,称为C群鼠。 2.饲养环境 种鼠组。A与C群鼠成年后     

实验动物呼吸系统主要器官比较组织学研究

目的比较实验动物呼吸系统主要器官的组织学特征,为制定实验动物病理检测标准、以及毒理学、新药安全性评价提供依据。方法选取实验动物质量国家检测标准检测合格的恒河猴30只、昆明小鼠20只、SD大鼠20只、日本大耳白兔18只、比格犬16只、树鼩20只。除昆明小鼠采用颈椎脱臼致死外,其余动物麻醉后放血处死和病理解剖,对气管、肺脏进行病理大体检查和取材,常规病理制片,进行HE染色、特殊染色和免疫组化染色,显微镜下观察气管、肺脏的组织结构和细胞结构异同。结果 （1）实验动物气管上皮杯状细胞有差异：恒河猴、比格犬、日本大耳白兔杯状细胞较多,大鼠、小鼠、树鼩则较少或无。上皮分泌的黏液类型以中性黏液为主,比格犬杯状细胞分泌的黏液类型有中性黏液和酸性黏液。（2）实验动物黏膜下腺泡分布有差异：比格犬黏膜下层的腺泡最多,恒河猴、大鼠、小鼠、树鼩腺泡数量偏少,日本大耳白兔黏膜下层的混合腺泡最少。（3）实验动物的肺内支气管分支有差异：比格犬、恒河猴、日本大耳白兔由叶支气管、段支气管、小支气管、细支气管、终末细支气管和呼吸性细支气管组成,树鼩、大鼠、小鼠只由细支气管、终末细支气管和呼吸性细支气管组成。（4）实验动物细支气管组织结构有差异：恒河猴、比格犬的细支气管平滑肌为完整环形平滑肌层,没有缺失,而大鼠、小鼠、树鼩及日本大耳白兔的细支气管平滑肌薄或缺失。恒河猴、树鼩、大鼠细支气管有少量杯状细胞,其余实验动物均无杯状细胞。（5）实验动物Clara细胞形态有差异：比格犬Clara细胞呈立方形,其余动物呈柱状。结论实验动物呼吸系统组织结构的质是相同的,差异在于量的不同。研究人员在制定病理学检测标准、实验研究、药物安全性评价时应予充分考虑。     

非人灵长类饲养与管理过程中的福利保障

实验动物饲养管理和福利保障的问题已越来越被国际社会所关注.与发达国家相比,中国对实验动物福利的研究及大众化意识则相对滞后.中国作为世界上最大的实验灵长类动物的饲养与出口国,每年遭受的国际贸易损失始终位居全球首位.为此,本文引入了实验灵长类福利的"5个自由"理论:1)动物有避免干渴、饥饿和营养不良等不利因素影响的自由;2)动物有获得舒适生活条件的自由;3)动物有脱离痛苦、受伤和疾病骚扰的自由;4)动物有表达自然行为的自由;5)动物有脱离恐惧和心理压力的自由.在上述理论的基础上,提高实验动物福利应具体从饲养的物理环境、营养供给、饲养管理、繁殖管理及饲养环境的多样性等几方面着手.通过总结国际与此相关的研究进展,旨为中国相关研究提供素材和为完善国内现行的法规及标准提出一些思路.     

实验小鼠流行性出血热病毒的监测

流行性出血热(EHF)是一种主要经过啮齿动物,特别是鼠类传播的人畜共患急性病毒性疾病。在卫生部医学实验动物微生物控制标准中,是一级实验动物应排除的病毒,必须进行定期监测,以便采取有效的预防措施,保证实验动物质量。本文采用间接免疫荧光法,对小鼠进行血清病毒抗体监测。实验动物计有昆明种、BALB/C、C3H、C57BL/G、615和NIH小鼠,均来源于成渝两地医学单位,开放环境中饲养;自眼眶采血,分离血清;抗原细胞片来自中国药品生物制品检定所;羊抗兔免疫血清由四川省卫生防疫站提供;羊抗鼠IgG荧光抗体购自北京军事医学科学院(批号8901);…     

实验动物的环境与福利

实验动物在生物科学研究领域中的应用不断发展,其饲养环境和福利保障的问题已越来越被国际所关注。实验动物的环境与福利不仅是对动物本身的保护,更重要的是对动物试验结果的保证。本文详细论述了大环境（温度、湿度、气流等方面）及小环境（笼具、饲养密度、垫料）对实验动物福利的影响,通过总结国内外的研究概况,旨为我国改善和提高实验动物的福利提出一些思路。     

高原鼠兔饲养管理和基本动物实验技术的建立

目的 建立高原鼠兔饲养管理技术和动物实验技术和方法 ,为该动物在生物医学研究中提供技术支持和服务平台.方法 在<医学实验动物学>和<动物实验方法 学>指导下,以科学、规范为原则,在实际工作中探索并反复试验,验证其可操作性.结果 建立了高原鼠兔饲养管理和卫生管理方法 ,建立抓取、标记、固定、麻醉、给药、取材、处死等11种动物实验基本方法 和技术.结论 为促进高原鼠兔进一步实验动物化奠定了必要基础,将有利于这一新型实验材料在生命科学研究领域得到更加广泛应用.     

啮齿类动物插管技术用于药动学采血的研究进展

近几十年来,人们持续关注实验动物的福利,并在全球范围的科学研究中整合、协调和监督实验动物的使用。"3R原则"是被广泛认可接受的标准和规范的核心要义和精髓所在。药代动力学研究中包含了必不可少的动物实验,如何保护实验动物福利是本专业发展到一定阶段和水平需要考虑的问题。国内外科研人员逐渐建立并优化在啮齿类动物(主要为大鼠和小鼠)上进行插管手术的技术,能让实验动物在清醒及自由活动状态下完成采血等实验。本文通过整理相关文献,对药动学研究中使用的插管技术进行梳理和总结,希望对国内该研究领域的实验动物福利保护有所助力。     

实验小鼠标记识别系统的优化

传统的实验小鼠标记识别系统包括染色法、打孔剪口法、刺花法、耳标签法和剪趾法等。随着小鼠作为动物模型在实验中广泛应用,人们对实验标记识别系统提出了简捷、易辨、持久、大编码量的新需求。本优化系统利用简单的数学方法改进剪趾法,使编码量扩大到9999,针对不同实验需求提供不同选择,并且在遵循动物福利的理念下,提出了一些建议。     

Long-term effects of husbandry procedures on stress-related parameters in male mice of two strains

In socially unstable groups of male laboratory mice, individuals may experience a chronic stress situation. Previous experiments have shown that the transfer of specific olfactory cues during cage cleaning, and the provision of nesting material decrease aggression and stress in group-housed male mice. In this study, the combined effect of these husbandry procedures were tested for their long-term effect on stress in groups of moderately aggressive (BALB/c) and severely aggressive (CD-1) male mice. The physiological and behavioural stress-related parameters used were body weight, food and water intake, spleen and thymus weight, adrenal tyrosine hydroxylase activity, urine corticosterone levels and behaviour in a cage emergence test. Long-term provision of nesting material and its transfer during cage cleaning was found to influence several stress-related physiological parameters. Mice housed in cages enriched with nesting material had lower urine corticosterone levels and heavier thymuses, and they consumed less food and water than standard-housed mice. Furthermore, marked differences were found between strains. CD-1 mice were less anxious in the cage emergence test, weighed more, ate and drank more, and had heavier thymuses but lighter spleens and lower corticosterone levels than BALB/c mice. We conclude that the long-term provision of nesting material, including the transfer of nesting material during cage cleaning, reduces stress and thereby enhances the welfare of laboratory mice.     

Evaluation of bedding and nesting materials for laboratory mice by preference tests.

Bedding and nesting materials can improve the health and environmental welfare of laboratory mice. This study was carried out to examine which items are actually preferred by mice. Two series of studies were performed on four types of floor-covering materials (Wood-shavings (Clean-chip), Cloth (Agrebe), Recycled-paper (Paper-clean), Paper (Care-feeaz), and on four types of nesting materials (Recycled-paper (Shepherd-shack), Cloth (Agrebe), Wood (Wood-cylinder), and Polycarbonate (Mouse-igloo). Preference of bedding materials was judged by the time length of staying in a cage. The results indicate that mice stayed in the cloth material (Agrebe) longer than in other bedding materials (light 51.1 +/- 5.3%, dark 51.5 +/- 2.6%). In the second experiment, the duration of stay in Agrebe was significantly longer than that in the other nesting materials in the light phase (70.9 +/- 2.4%). In the dark phase, staying time both in Agrebe and Shepherd-shack were significantly longer. These data suggest that cloth bedding and nesting is recommended for the environmental enrichment of laboratory mice.     

Behaviour of laboratory mice in different housing conditions when allowed to self-administer an anxiolytic

Standard cages prevent mice from performing several natural behaviours for which they are motivated. As a consequence, abnormal behaviours sometimes develop and mice often spend long periods inactive. To improve welfare, cages are sometimes furnished with items such as nesting material, shelters and running wheels. We have previously reported that when allowed to self-administer an anxiolytic, mice in furnished cages consume less anxiolytic than mice in standard cages. This paper presents the results of behaviour studies of the mice in the same experiment. Female C57BL/6J mice (3 per cage) were housed in Standard (n = 10), Unpredictable (n = 10) or Furnished (n = 6) cages. Unpredictable cages were identical to Standard cages, but were exposed to unpredictable events two to three times a week. Furnished cages were double the size of Standard cages and contained nesting material, nest box, tubes, chew blocks and a running wheel. During three consecutive periods, mice had access to only water (control), water or an anxiolytic solution on a daily alternating schedule (forced consumption), and finally, both water and anxiolytic (self-administration). Behaviour was analysed from video recordings taken during the dark phase. The housing type affected behaviour both under the control and the self-administration conditions. Overall, mice in Furnished cages spent less time resting and performing bar-related behaviours and more time on exploratory/locomotory behaviours. Mice in Furnished cages also performed less bar-circling stereotypies than mice in Standard cages. The Unpredictable treatment did not significantly affect behaviour compared to mice in the Standard conditions. There was an overall effect of anxiolytic availability on rest-related behaviours and on exploration-locomotion behaviours, in that mice rested more and spent less time on exploration and locomotion when they were able to self-administer the anxiolytic.     

The effects of enriching laboratory cages using various physical structures on multiple measures of welfare in singly-housed rats

The single housing of laboratory rats may be recommended in some situations such as hypothesis-driven or test-specific studies, during electroencephalogram recording of phases of sleep and after surgical procedures. However, as single housing of laboratory rats has been shown to be stressful, modification of the housing environment is needed to improve the welfare of these animals. This experiment was carried out to investigate the long-term effects of environmental enrichment on some behavioural, physiological, pathological and psychological measures of welfare. With two batches of animals, 24 rats were housed singly in either enriched cages (EC) (n = 12 cages) or unenriched cages (UC) (n = 12 cages). Behaviour was sampled every week and so was body weight and weight gain over a six-week observation period. Behaviours of the rats in the elevated plus-maze were recorded on the seventh week, whereas organ weights were recorded postmortem. The results revealed that long-term single housing of rats in super-enriched cages increased levels of indicators of good welfare including sleep, exploration, movement and feeding behaviour, body weights, weight gains and the relative weights of the thymus gland and spleen, and decreased levels of indicators of poor welfare such as stationary behaviour and the relative weight of adrenal glands. Thus, enrichment of conventional cages of newly weaned singly-housed laboratory rats with multiple physical structures appeared to improve their ability to control the environment and to promote their species-specific behaviour; changes that can ultimately result in good welfare.     

The effects of enhancing cage complexity on the behaviour and welfare of laboratory rats

This experiment was carried out to investigate the long-term effects of enhancing cage complexity on behavioural measures of welfare in laboratory rats. We housed 72 rats in groups of four in either ‘enriched’ or ‘unenriched’ cages for six weeks. Scan and focal animal sampling were conducted in both the light and dark phase of the second, fourth and sixth weeks. Results revealed that rats in the ‘enriched’ cages showed longer durations of sleep behaviour, and low levels of agonistic behaviour compared to rats in the ‘unenriched’ cages. Results importantly demonstrated that the behavioural changes observed in the enriched environment were due to the presence of the enrichments themselves in the cages (indirect effects) and not due merely to rats interacting with the enrichment items in their environment. Thus, enhancing the complexity of conventional laboratory cages can promote behaviour such as longer bouts of sleep that is likely to be indicative of good welfare, and diminish levels of behaviour such as aggression that is likely to lead to poor welfare.     

Modifications to husbandry and housing conditions of laboratory rodents for improved well-being

For a change to be considered enriching, the change must enhance animal welfare and improve biological functioning of the animals. A review of the literature shows that a consensus on the definition of changes constituting "environmental enrichment" has yet to be reached. For this reason, the results of studies on the effects of rodent enrichment are inconsistent. In many cases, changes have not been shown to be real improvements. However, enrichment is increasingly appreciated as a way to improve the well-being of rodents, providing them with opportunities for species-specific behaviors that might be available to them in the wild. Frequently defined as "change to the environment," enrichment can be as complex as devices (frequently termed "toys") or as simple as the provision of tissues from which mice readily construct nests. Nest making is a learned behavior in rats, and laboratory rats do show preferences for chewable objects in their environment. Rather than attempting a comprehensive review of the entire literature on environmental enrichment and its effects on rodent physiology and behavior, this paper focuses on husbandry and housing alterations that may improve the welfare of laboratory rodents. The effects of beneficial changes in housing and husbandry on rodent well-being and on experimental variability--and thus cost--are discussed. Areas that require more research are suggested. Also suggested are possible inexpensive and effective enrichment schemes for laboratory mice that might include reducing the cage floor space per mouse combined with providing nesting material.     

Cage enrichment with paper tissue, but not plastic tunnels, increases variability in mouse model of asthma

Environmental enrichment, besides having a great impact on animal welfare, can also be a potential variable in experimental research. Thus, we investigated whether enrichment of cages with paper tissues or plastic tunnels affects scientific outcome in the well-described mouse model of allergic asthma. BALB/cJ mice were introduced to paper tissues as nesting material, transparent plastic tunnels serving as shelters or kept in non-enriched cages. Afterwards, mice were sensitized to chicken egg ovalbumin (OVA) precipitated in aluminium sulphate and then intranasally challenged with OVA to induce allergic lung inflammation. Mice housed in cages enriched with paper tissues, but not with plastic tunnels, had increased total cell number, eosinophil number and IL-13 concentration in bronchoalveolar lavage fluid in comparison with the non-enriched control group. These results indicate that the effect of environmental enrichment on mice asthma models depends on the type of enrichment used. Therefore, it is important to consider the potential effects of any environmental enrichment on animal welfare and more importantly, on research results in order to standardize and obtain more accurate data from rodent studies.     

Nest Building as an Indicator of Health and Welfare in Laboratory Mice

The minimization and alleviation of suffering has moral and scientific implications. In order to mitigate this negative experience one must be able to identify when an animal is actually in distress. Pain, illness, or distress cannot be managed if unrecognized. Evaluation of pain or illness typically involves the measurement of physiologic and behavioral indicators which are either invasive or not suitable for large scale assessment. The observation of nesting behavior shows promise as the basis of a species appropriate cage-side assessment tool for recognizing distress in mice. Here we demonstrate the utility of nest building behavior in laboratory mice as an ethologically relevant indicator of welfare. The methods presented can be successfully used to identify thermal stressors, aggressive cages, sickness, and pain. Observation of nest building behavior in mouse colonies provides a refinement to health and well-being assessment on a day to day basis.     

Improving housing conditions for laboratory mice: a review of "environmental enrichment"

Laboratory animal facilities have been designed to provide a standard environment where animals can be kept in good physical health at the same time as economic and ergonomic considerations are met. Recognizing the potential welfare problem associated with behavioural restriction in such housing systems, a number of attempts have been made to improve this environment, generally described under the term "environmental enrichment". Modifications of cages for mice usually consist of providing material for nest building and structures which can serve as hiding places and/or for climbing. We have reviewed 40 studies carried out between 1987 and 2000, in which preferences as well as the effect of housing modifications have been studied. Mice will work for access to nesting material and make use of this material to make nests in which they rest. They prefer a more complex cage to the standard cage and will also work for access to cages with shelter and raised platforms. On the basis of present knowledge, it is recommended that mice should have access to nesting material. Strategies for future research are outlined in the article.     

Aspen wood-wool is preferred as a resting place, but does not affect intracage fighting of male BALB/c and C57BL/6J mice

Aspen wood-wool, provided as nesting material, was evaluated as a possible improvement of cage environment for 10-14-week-old inbred male mice maintained in groups of six (BALB/c n = 72 and C57BL/6J n = 36). The daily behaviour of mice was video recorded and their body weight, food consumption, weights of some organs and serum corticosterone concentrations were measured. Aggressive interactions between cage mates and against a strange intruder as well as the number of wounds on the back of the animals was monitored in order to evaluate the effect of nesting material on intermale aggression. Nesting material did not affect the daily active/passive behaviour patterns of mice, although animals clearly preferred it as a resting place. BALB/c mice given nesting material showed less weight gain and smaller brown adipose tissue weights than animals without nesting material. The other characteristics measured were not affected by the presence of nesting material in either strain. The presence of nesting material had no effect on fighting in cages. C57BL/6J mice were more aggressive than BALB/c mice according to the number of wounded animals in a cage. Wounded BALB/c mice had enlarged spleens and decreased epididymal adipose tissue weights. In conclusion, the nesting material used in this study did not adversely affect the animals. On the other hand, the material was clearly preferred to conventional bedding as a resting place. These findings suggest that nesting material may improve the cage environment of laboratory mice. Furthermore, there was an indication of strain differences in aggressive behaviour. It could be suggested that C57BL/6J mice are less tolerant towards intruders and housing six mice per cage is not suitable for this strain.