Animal Testing; Alternatives Used for Laboratory Animals Education and Research
(Dr. Amrita Behera, Ph.D Scholar, Indian Veterinary Research Institute, Dr. Deepak Sakhre, Livestock Development Officer, Maharashtra)
INTRODUCTION
The genesis of the concept of the term “alternatives” to the use of animals in research and development can be well traced back to the 1800’s when there was a furore about the use and technicality of using live animals in surgical or other experimental procedures. The animal protection societies in England then started to accept the concept of animal experimentation provided that it was performed under the supervision of anesthesia. For record, Dr. Marshall Hall, known to have championed the spread of experimental medicine in 19th century the then England, considered it imperative to prevent and control unjustified, incompetent and harsh experimentation. It was in the 20th century that the concept of alternatives was originated to take into consideration not only the reduction of the pain induced while experimenting but also the total replacement of use of animals in research.
The important goals of the industry involves there has to be widespread agreement for the reduction of number of animals and the clarification of testing. The insilico computer stimulation and invitro cell culture proves to be the alternative to invivo animal testing. Though, many reports claim them not to be the true representatives because simulations use data from prior animal experiments and cell cultures often require animal derived products, such as serum or cells. Also many points claim at that animals cannot be replaced as they are unlikelyto provide sufficient information about the compound interactions of living systems. Other alternatives also sets to include the use of humans appropriate for skin irritancy tests and in case of human blood for conducting pyrogenicity studies. A novel alternative is microdosing which asses the basic behaviour of drugs using human volunteers receiving doses lower than those expected to produce entire-body effects. While revealing information about pharmacokinetics and pharmacodynamics, it fails to reveal information about the toxicity effects.
Hence, as applicable to the use of animals in different laboratory programs, an alternative is any system or method which covers following agendas:
- Replacing the use of laboratory animals altogether;
- Reducing the number of animals required;
- Refining an existing procedure or technique so as to minimize the level of stress endured by the animal.
These have been popularly well described as the three R’s (Three Rs (3Rs) first described by Russell and Burch in 1959) and therefore, in combination justifies for the term “alternatives”. Adding to it, an alternative must also provide information and outcomes which allow the researcher with the same degree of confidence to draw the same conclusions. Each of the three aspects is described below
Replacement : describes the favorable use of non-animal methods over animal methods to achieve the same scientific aim if the cicumstances allows for the same conditions. Complete replacement of laboratory animal use occurs relatively infrequently. For example-The field of vitamin research is one such area where replacement has effectively been taken place. The early animal assay systems is now being replaced by the use of physico-chemical methods. For example, it is now possible to replace the biological (animal) assay systems for vitamins A,D and E by physico-chemical techniques
Reduction: describes the methods that allow it to obtain comparable levels of information from a few animals, or to obtain in large information from the same set/number of animals. This aspect of using alternatives shows maximum potential. First, a carefully designed experiment could reduce the demand for laboratory animals. For example, a study in 1961 by an independent statistics consultancy showed that the number of animals used in a randomly selected sample of published research reports could have been reduced by 25-43% with no loss of statistical validity.The analysts confined their study solely to the question of sound statistical design and analysis. Second, before starting the experiment the researcher should be assured that the problem being looked into is worth solving and that the experiment should confirm n involvement of needles duplication of previous work. Third, the research should also ensure that the animal model being proposed for the study is the most relevant one that is available. The selection should be based on such factors as availability, level of sentience (where possible) and the potential relevance of the
Refinement : describes the methods that minimizes inflicting pain, distress, hardship/suffering and magnify the welfare of the animals being used. Stress (pain and suffering) is an undesirable factor (from both scientific and humanitarian view points) in animal experiments unless the research is specifically concerned with stress or its effects. Stress may occur during the housing of the animal before and after the actual experiment. Any refinement in research techniques or standards of husbandry which could reduce stress will, therefore, qualify as an alternative.
The scope for developing and using alternatives varies according to the objectives of the particular laboratory activity using animals
- Biological and Medical Education: For imparting practical experiments in secondary level and university levels for educational purposes at least 3 million animals per annum are
- Toxicity Testing: The testing determines whether chemicals are ‘safe’ for general human use or the ‘safe’ limits of use for chemicals known to be hazardous. Tests are conducted using a wide range of chemicals and biological
For especially new drugs, the standard toxicity tests include methods that determine the toxic effects of a single dose i.e. acute toxicity, of many repeated doses i.e. chronic toxicity and detection of certain exclusive effects such as the induction of genetic damage, the induction of cancer or the induction of deformities in the developing fetus.
- Original and Applied Research : Based on hypothesis, design of experimens, hypothesis on results of
WHAT ARE THE ALTERNATIVES?
A) Physico-Chemical Techniques
Its development plays an integral part for the improvement of biomedical knowledge of the structure as well as function of living organisms. These techniques tend to analyze the physical and chemical properties of the test biochemicals. Citing examples is the mass spectrometry and gasliquid chromatography which are very delicate techniques for separating, identifying and measuring the amounts of individual substances in complex biological mixtures.
B) Culture of Single-Celled Organisms
Free-living organisms such as Bacteria and protozoa can be cultured in the laboratory comparatively easily and can be hence used as models of citing basic life processes. Taking bacteria as an example, it is being used extensively in the study of the basic mechanisms involved in the replication of genetic material and proteins. They have also been used in nutritional research and there are a variety of bacterial and protozoal systems which can be used to assay vitamin concentrations. Validating the efficacy of using bacteria is the development of alternatives is their use in the Ames test to detect potential mutagenic and carcinogenic substances. It employs Salmonella bacteria to detect substances which can cause effective mutations in the genetic material.
C) Mathematical and Computer Modeling
Computer modeling is a very worthy tool used in biomedical research and this can be applied more widely for the context of using alternative. A model is a simplified representation of the system under investigation and is a useful device for studies that involve altering several variables at the same time. Computer and mathematical models are based on the use of equations of varying degrees of complexity to represent biological phenomena. Utilization of sophisticated modern computers permits the investigator to employ complicated mathematical functions in the construction of viable and detailed models of biological systems. The computer models also can be employed to search and look for investigations for the problems in a manner not possible in the living animal. However, computer models cannot completely rule out animal experimentation since results obtained from these simplified models will have to be checked by experiments on the far more complex living systems.
D) Tissue Culture
Organotypic culture: An organ is cut into small pieces, usually no more than a few cubic millimeters in volume, and placed in contact with an appropriate nutrient medium.
Cell culture: Individual cells are separated by mild enzymic digestion and then grown in suitable containers. The advantages include:
- The ability to grow large quantities of standarized material;
- The ability to study living material under well-defined conditions;
- The relatively compact and inexpensive storage and handling facilities. The disadvantages include:
- cells after subculturing tend to lose the specific properties that initially they had in the body;
- whole body metabolism is only partially mimicked in cell
E) Clinical and Epidemiological Studies:
Human beings can be extensively employed to be used as an experimental animal. For example, new drugs which have passed the animal testing stage are tested on selected human volunteers because one cannot extrapolate from animals with complete confidence. In addition, much valuable information on disease processes can be obtained from clinical case studies and autopsy reports.
F) Other Techniques:
Some other novel techniques also contribute to be used as alternatives effectively. For example, animals being used in crash studies. Animal models can also be replaced by mechanical models e.g. Thermoman which is a human simulator can test the potentiality of risks of burn with different garments.
References
- Adamiker, D. (1977). Breeding of Laboratory Animals in Austria. Wien. Med. Wochschr. 127: 1 72-1
- Alderson, M.R. (1977). The Role of Epidemiology in Cancer Control. A TLA Abstracts 5(2): 12-18.
- Anonymous (1966). Information on Laboratory Animals for Research. 9(3): 1
- Autian, J., Dillingham, E.O. (1978). Overview of General Toxicity Testing with Emphasis on Special Tissue Culture Tests. In In Vitro Toxicity Testing; 1 975-1 976 (eds. J. Berky & C. Sherrod), Frankl in Institute Press: Philadelphia, pp. 23-49.
- British Pharmacopoeia (1973). Biological Asa y for Tetanus Antitoxin. British Pharmacopoeia Commission: London, p.
- British Pharmacopoeia Addendum (1977). Biological Assay for Tetanus Antitoxin. British Pharmacopoeia Commission: London, p.
- Bucknall, R.A. (1979). The Use of Cultured Cells and Tissues in the Development of Antiviral Drugs. In The Use of Alternatives in Drug Research (eds. A.N. Rowan and C.J. Stratmann), MacMillans: London
