Why do people still use animals in testing?

The main reason is that the perceived similarities between animals and humans are often used as the justification for animal experimentation and seems more humane than testing potentially hazardous materials on live humans! It is presumed that because we share similar biological processes, and because animals are whole, complex organisms, data obtained from animal models can be extrapolated and applied to humans. Even species who share close evolutionary relationships or anatomical similarities differ in important ways which calls into question the usefulness of animal models as mimic for humans.

Major differences in human biology and physiology

It’s widely quoted that we share 98% of our DNA with mice but we know that there are some major differences in our biology and physiology, important differences when it comes to how we react to things being put on and in our bodies. Non-human animals have different genetic backgrounds that make them unique—and ill-suited to serve as predictive models for people. “Even when researchers have discovered an animal model which appears to mirror what occurs in humans, the response observed in animals can occur via different mechanisms due to the intrinsic differences between species.”

According to Genoskin, “The most used animals to study skin response are small mammals like rabbits, guinea pigs, rats and mice as they are inexpensive and easy to handle. Some large animals like pigs are less used due to their long gestation time and the need for larger and adapted facilities.” But when we look at the similarities and differences of these animals, we can see why we need to develop human-relevant tests for ALL safety and efficacy testing. Pig skin was long regarded as a very close representation of human skin however further studies reveal subtle differences which could skew results. Not to mention the cruelty and inhumanity of using such an intelligent and charismatic creature.

John Sheasgreen, then president of MatTek corp: “The rabbit is not a particularly good model for human irritation or corrosion, largely because the barrier properties in rabbit skin are far less robust that in the human.” He explains that when his company compared results from chemical testing on their in vitro skin with available human and rabbit data, the “in vitro model correlates much better with the human experience than the rabbit experience.”

So why is animal-product-free “better science”?

Many in vitro test methods still use animal-derived components such as Foetal Bovine Serum (FBS), tissue extracts and antibodies.
However, an increasing body of evidence shows the importance of having a system that models human physiology as closely as possible, rather than relying on the use of animal-based culture systems. The significant ethical issues surrounding the use of animal-derived components, especially FBS, have also been well documented. FBS is derived from blood extracted by cardiac puncture of lliving, unanaesthetised, calf foetuses.

At XCellR8, we’ve invested years of research into developing adaptations of existing safety tests, where all animal components have been eliminated. In their place, we use human-derived serum and antibodies from approved sources as well as chemically defined products. This approach maximises both the human relevance and reproducibility of the test results. Our adaptation of the skin sensitisation test KeratinoSens™ is now incorporated into OECD Test Guideline 442D. We also have several projects underway to ensure APF versions of other TGs become available for regulatory use.

Do you have a product or ingredient needing safety or efficacy testing? Or do you just want to find out more about our animal-free tests? Get in touch today!

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