Among different ways that we have learned whether and how a chemical substance (or such physical properties as radiation or gravity) may cause short- or long-term harm to us, is to test the impact of the substances or properties in what scientists call model systems. Some of this testing may be conducted in glassware or other materials (for example glassware or petri dishes) either with living tissue such as cells in cultures, tissues obtained from experimental animals, specially-fabricated tools known as microarrays or with purely chemical systems. This is known as in vitro testing. Sometimes testing is conducted using living organisms, or laboratory animals, and is known as in vivo testing. Recently, a new approach to testing involves the evaluation of substances or physical properties using computer models. This is known as in silico testing. For example, physiologcally-based pharmacokinetic models or PBPK models are a computer-based or "in silico" method of predicting how a contaminant might behave in a living system. Though these models may initially rely on information collected from "in vitro" or "in vivo" studies, they may one day be used to predict effects of chemicals or mixtures of chemicals for which such studies have not been conducted (or not as many) thereby reducing our reliance on animal testing.
Each of these model systems has its limitations; but, in recent years the most problematic has been in vivo testing—the type of testing that is conducted utilizing humans as well as animals. The scientific community, regulators, the public and the private sector have each called for—in some way—the advancement of testing protocols away from the in vivo testing model. They have called for the development of alternatives to animal testing.
Among the ways for us to learn whether and how a substance or physical property will harm people—and domesticated and wild animals—involves often complicated study. For chemical substances, learning about potential harm requires determining how the living organism absorbs, uses, and releases the substance. For some of these chemical substances, animal testing may be necessary to expand our understanding of the substances effects—since, except in special, regulated circumstances human testing is not allowed. For example, animal testing has and continues to help in identifying and understanding such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method (model) for getting information needed to make wise decisions that protect public health. Animal subjects are used in the evaluation of chemical substances (that may be toxic or hazardous, or that may be disruptive of vertebrate endocrine systems), drugs, cosmetics, and foodstuffs.
Protecting Animal Subjects
Scientists, of course, have the responsibility—and are required by statute—to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals. When animals are to be used as test subjects, researchers must comply with the Animal Welfare Act. Under the regulations written to implement the Act, scientists must consider what alternatives to animal testing they can use in their investigations prior to beginning a project.
Today, there are vigorous, ongoing national and international research and policy efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validation—and regulatory and public acceptance—of innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal-based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM).
- Agency for Toxic Substances and Disease Registry
- Animal Welfare Act (7 USC 2131-2156)
- Center for Alternatives to Animal Testing
- European Centre for the Validation of Alternative Methods
- Institute for Laboratory Animal Research
- Interagency Coordinating Committee on the Validation of Alternative Methods
- National Institute of Environmental Health Sciences Microarray Group