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NO CONSISTENT DIFFERENCE BETWEEN FIELD AND LABORATORY ANIMALS

   Vittorio Hernandez 기자   2018-03-17 00:00
Photo By Elnur Amikishiyev via 123RF

 

Because it is a common practice in biological sciences to use animals maintained in the laboratory to draw conclusions about the ecology and evolution of animals in the wild, researchers decided to compare results using both field and laboratory animals.  Their aim was to check the assumption that laboratory populations represent their wild living counterparts.

When the researchers looked for previous studies, they found 28 relevant studies on seven orders of invertebrates or a total of 777 traits, Scientific Nordic reported. But the studies did not show any significant trend in the size, lifespan, or stress tolerance of the animal studied.

No evidence

The researchers failed to find any evidence that the laboratory animal has been changed because it was raised in a lab. The lack of any consistent pattern was evident even if the team limited their search of the Drosophila, a type of fly.

Because the Drosophila is a popular laboratory animal, it has numerous laboratory stocks of multiple species available globally. Scientists who do not have time or resources to collect fresh samples of the fly for each experiment can tap the stocks available.

The researchers got nine newly collected populations from the same location as nine existing Drosophila laboratory populations with assistance from scientists in Australia, Japan, and the US. They tested 12 traits, including the fly’s ability to cope with stress, particularly the lack of food and water, exposure to harsh temperatures, how big and fat the fly was, how it reproduces, how long the species lives, and how active the Drosophila is.

Although the team found that while the field and laboratory populations of the flies can be a little different from each other, there is no consistent difference. One such difference, although it is not consistent, is that the flies from the lab sometimes died sooner than the field flies. However, it was not an indicator that the lab flies were substantially different compared to wild flies.

The verdict of the team is that the biggest difference in traits happened among the different species instead of whether it was kept in a lab or in the wild for several generations. The implication is that it is okay to use the lab animals for comparative studies and even ecological studies.

No significant difference

The researchers found no significant difference in the ecological trait correlations between the animals from the recent collections and those from the lab. Creatures that came from the cold environment were still better at coping with cold, even after it was made to live in a cozy laboratory environment compared to those that came from warm environments.

The conclusion was that 20 or even 100 generations in the laboratory environment is not enough to undo the millions of years of evolution that created the species differences. The laboratory flies did not become soft because in a constant lab environment it has easy access to food, water, and mates.

The relief that it offers for researchers is that they do not have to go out in the field and collect wild specimens every time they need to do an experiment involving animal models. The study was published in the Journal of Evolutionary Biology.

 

Photo By Vit Kovalcik via 123RF

 

Virtual lab animals

Among the most popular animals used in the lab are rats, mice, rabbits, and other creatures that have long played a big role to evaluate the safety and effectiveness of drugs before these undergo their first clinical trials involving humans. The Talking Democrat estimated that around 60,000 animals are used each year around the world in labs for tests and studies.

To avert animal suffering, a team from Oxford University developed a computer simulation which can predict if drugs are toxic to the heart or not. Virtual Assay, the software, uses a model of the human heat cells which makes it possible to eliminate from the outset medication that is toxic to the heart without using text animals.

The model was able to predict if a drug or a compound could cause an irregular heartbeat, arrhythmia, in 89 percent of the time. When researchers performed a similar test on cardiac cells of rabbits, the test was effective only 75 percent of the time.

Elisa Passini, a researcher at Oxford’s computer science department, said these new models could save many animals one day and avoid killing the creatures in the name of science. She noted that the current strategies to evaluate the cardiotoxicity of medications involve using various animal species for preclinical studies. It can go beyond the use of 60,000 animals a year.

But while the new virtual tests are apparently more effective than animal tests, it remains unseen if the option could be extended to all types of test. The researchers are currently holding virtual studies in the areas of type 2 diabetes and pain research. For the study, published in September in Frontiers in Physiology, the researchers won the NC3Rs award given by the National Center for the Replacement, Refinement and Reduction of Animals in Research.

[researchpaper 리서치페이퍼= Vittorio Hernandez 기자]