Jun 11, 2022 09:00:00

'Mice and rat breeding environment used in experiments' may change research results

In research in the medical field, many animal experiments using not only human patients but also mice are conducted, and 120 million rats and mice are used in the experiments every year around the world. However,

Georgia Mason et al., A professor of biology at the University of Guelph , Canada, said, 'Chronic stress from the environment in which the experimental animals are raised may cause biological changes and affect the experimental results. There is sex. '

Conventional laboratory housing increases morbidity and mortality in research rodents: results of a meta-analysis | BMC Biology | Full Text
https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-021-01184-0

Laboratory mice are usually distressed and overweight, calling into question research findings
https://theconversation.com/laboratory-mice-are-usually-distressed-and-overweight-calling-into-question-research-findings-175812

Researchers are using rats and mice to study various diseases such as cancer, arthritis, and chronic pain, and the results are used for human research and treatment. However, if the breeding environment of the experimental animal itself affects the health condition, it will also change the experimental results and hinder accurate research.

Therefore, Mason et al.'S research team extracted data from more than 200 studies investigating diseases such as cardiovascular disease, cancer, stroke and stress in mice or rats, and the 'domestic environment' is the animal. We analyzed the effects on health.

When the research team compared the experimental animals raised in the 'conventional small cage' with the 'cage with a wheel, nest box, ample space, playground, etc.', the experimental animals raised in the overall small cage It turned out that people are more likely to get sick and the degree of illness is severe. They also reported that laboratory animals kept in small cages had a higher risk of death and a life expectancy of 9% shorter.

The results of this study suggest that rats and mice living in narrow, mild cages may not be suitable models for experimental animals. Past studies have also pointed out problems such as the fact that experimental animals are

biased toward males, many are overweight, are bred in an environment colder than the appropriate temperature, and have low cognitive ability .

The researchers suspect that these problems with laboratory animals may be responsible for the ' poor reproducibility in biomedical research .' Past studies have already shown that completely different experimental results can be obtained depending on the breeding environment of the experimental animal, and Mason et al. Are trying to evaluate how often this problem occurs.

A 2015 study pointed out that '50% of preclinical study results cannot be reproduced by other research teams,' but if this includes tens of percent of laboratory animal-derived failures, each year. Huge amounts of money may have been spent on 'barren research that cannot be reproduced due to the poor breeding environment of the experimental animals.' Since only a few percent of the promising results of preclinical research can be applied to humans, improving the breeding environment for laboratory animals is of great ethical and academic significance. ..

Mason argues that cages in which rats and mice live should not be ignored as unrelated to the experiment, but should be recognized as an important determinant of health, modified and improved. 'By doing so, we will be able to better model the diverse social determinants of human health and at the same time improve the well-being of animals,' he said.