Limitations on the use of Animal Data in Toxicology
|Topics:||Animal Rights, Animal Testing, Health, 🐰 Animal Welfare|
Diversity of factors to toxicology, which includes exposure to environmental hazards, pharmaceuticals, and feed additives, establishes the need for protective measures against exposure and effects of toxins. Animal data, derived from vertebrates and especially its sub-class of mammals, has been used, in toxicology, though the use face limitations. The limitations and need for care in generalizing the data from animals to humans are discussed.
The use of animal data in toxicology faces ethical and legal constraints that point to the need for alternatives. The European Union, for example, has regulations on animal research that restrict research into animal data (Scholz et al., 2013). The high number of animals used for the generation of the data, for use in toxicology is one of the bases of the constraints whose perceived significance has motivated perceptions of the need for alternative data sources. Member states of the European Union, for example, used 12 million vertebrates in the year 2008 to generate scientific data whose applications include toxicological assessments (Scholz et al., 2013). Millions of fish are also being used per year for scientific evaluation (Scholz et al., 2013) and the effects of the use of the animals define some of the limitations of the usage. Threats of extinction that is likely to reflect on the economic and social significance of animals, especially if usage can affect the lifespan or productivity of the used animals. Animal use as a source of data on toxicology aims at ensuring the safety of humans using animals to evaluate safety of possible hazards means exposure to the animals to unknown risks. The use of fish and birds to evaluate environmental hazards and risks in the European Union, and based on the high number used (Scholz et al., 2013), explains possible extinction as a limitation on animal data and calls for alternative data sources explain this.
In addition to the use of alternative sources of data for hazards and risk assessment, calls have been made for the reduction of the use of animals in scientific research, including toxicology evaluation, and refinements in the use of animals as data sources. The ICCVAM and the NICEATM support the need for reduction, refinement, and replacement initiatives in the use of animals because of the associated effects of the usage of the animals (Stokes, Kulpa-Eddy, & McFarland, 2011, p. 2). Pain and stress that the usage can cause on the animals are some of the factors to the need for reduction, refinement, and replacement of animal data. The usage also exposes used animals to pathogens and the effects that can be transmitted to offspring of the used animals. The effects can also be transmitted to other animals that consume the used animals and define other concerns into the need for reduction, refinement, and replacement options to animal data in toxicological assessments and other scientific research (Stokes, Kulpa-Eddy, & McFarland, 2011; Doke & Dhawale, 2013). The ethical concern around the need for refinement, replacement, and reduction of animal data, as well as the effects of animal research define a limitation of the use of animal data in toxicology.
The approaches and models for generating animal data, in addition to the ethical limitations on the use of animal data, also identify limitations. The approaches for the generation of animal data are consistent with the experimental research methods but lack some necessary features for a high level of reliability and validity. Confounders are some of the threats to reliability and validity, and the generation of animal data identifies threats of confounds due to diseases (Morgan, Elangbam, Berens, Janovitz, Vitsky, Zabka, & Conour, 2013). Exposure of an animal to a substance, for understanding for the potential risks of the substance on humans, therefore, may suffer from confounding effects of the substance and undermine an observation of the effects of the exposure. Some effects of exposures may be significant after a long period, and the short lifespans of some animals may undermine the ability to observe effects. Longitudinal studies are necessary for evaluating such effects, but may not be effective if the lifespan of the suitable animal is less than the threshold period for manifestation of effects of the subject exposure. Heterogeneity of body responses and inability to control the history of an animal are other limitations that have been associated with the generation of animal data for the use in toxicology evaluations and other scientific analyses (Morgan et al., 2013). Materialism, bias, and lack of accountability also threaten validity and reliability of generated animal data to identify limitations on the data for use in toxicology (Green, 2015). Measures such as testing of research instruments and other aspects of research methodologies, however, can address the threats to validity and reliability (Karuth, Woodruff, & Berro, 2013). Possible variations in effects of exposures and homeostasis between animals and humans identify another limitation of the use of animal data. An observed effect, due to exposure, from animal data may not be similar to an equivalent exposure in humans (Burghoff, Wikoff, Harvey, & Haws, 2016) and this supports the unreliability of animal data for use in toxicology.
Care needs to be taken while extrapolating results from animal data to humans because of the validity and the reliability concerns that define limitations of the animal data for use in toxicology and other scientific research initiatives (Morgan et al., 2013; Green, 2015; Karuth, Woodruff, & Berro, 2013). Validity and reliability are fundamental to generalizability of research findings and threats to them undermine the confidence with which findings can be extrapolated from a sample to a population and from a population to another. Consequently, existence of such limitations as confounders, bias, and other methodological limitations must be investigated and extrapolation can only be done if no methodological limitation is significant.
The use of animal data is important to toxicology and other scientific research initiatives. Ethical and legal constraints are some of the limitations of animal data because of the effects on the ability to generate the data. Methodological constraints that undermine the validity and reliability of animal data also identify limitations of the data for use in toxicology. The methodological limitations identify threats to the ability to extrapolate animal data to other populations, such as humans and this explains the need for care when extrapolating animal data to humans.
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