A new test using protozoa — single-celled organisms — has been developed by U.K. researchers, who say it has "great potential" for reducing the use of animals to determine the safety of cosmetics. 

Scientists at the University of Liverpool have been working on a way to determine the potential toxicity of mascara, which can irritate the eyes.

'It could be used on all kinds of cosmetics that are potentially toxic.… The basic premise could be applied all over the place.' — Dr. David Montagnes, Canadian ecologist involved in Liverpool mascara test project

Mascara has historically been tested on the eyes of rabbits, to determine its safety, but that method has led to ethics and animal cruelty debates. The effectiveness of testing products for humans on animals has also been questioned.

"This [new] test has great potential for reducing the use of rabbits as it is both cheap and reliable,” Dr. David Montagnes, the Liverpool project’s supervisor, said in a release. The Canadian ecologist, who is now based in the United Kingdom, added that the protozoa have a similar metabolism to animals, but aren't classified as animals. 

The traditional test used on rabbits, the Draize test, was developed more than 60 years ago and is time-consuming, expensive and gives rise to ethical issues, Montagnes said.

The U.S. Food and Drug Administration doesn't specifically require companies to test on animals, but says it's up to manufacturers to ensure their products are safe before they can be sold. In Canada, animal welfare legislation differs by province, although the Canadian Council on Animal Care has a set of guidelines that addresses moral and ethical issues of using animals in scientific research. Meanwhile, in the EU a complete ban on testing cosmetic products and ingredients on animals went into effect earlier this year. 

The new research, which is still in the early stages, is published in the most recent issue of the International Journal of Cosmetic Sciences. It was part of an undergraduate project led by final-year student Hayley Thomason.

Toxicity test

A team from the University's Institute of Integrative Biology used two different protozoa — Paramecium caudatum, also known as slipper ciliate, and Blepharisma japonicum, appropriately nicknamed eyelash ciliate.

The two species were chosen specifically for their large size, making them easier to see, as well as their historic use as model organisms and their genetic similarities to humans.

Six randomly chosen commercial brands of mascara were painted onto small glass plates — called cover slips — in different concentrations, some left bare as a control. The cover slips were placed, mascara-side up, into the bottom of wells containing bacteria that would allow the protozoa to grow. Ten protozoa cells were then added to each well and left to sit in an incubator for two to four days.

animal  conjugation of Paramecium caudatum

Paramecium caudatum, nicknamed slipper ciliate, are about half a millimetre long. (iStock)

"What we wanted to do was develop a test that didn't kill the protozoa, but inhibited their growth," Montagnes told CBC News in an interview Friday. He said the goal was to see how the mascara slowed the organisms' division rate in a process called sublethal bioassay.

Using a microscope, scientists visually counted the number of protozoa and measured their population growth to determine the potential toxicity caused by each mascara. They found that some brands killed the protozoa, some slowed the growth rate, while others didn’t harm them at all.

"If there was a slight toxicity of the mascara, the [protozoa] grew up slower than if there was no toxicity," Montagnes said.

Montagnes, who has done research at the University of Guelph in Ontario and the University of British Columbia, said this method could potentially be used to test cosmetics besides mascara, including lipstick or perfume.

"It could be used on all kinds of cosmetics that are potentially toxic.… The basic premise could be applied all over the place, to anything you could paint onto a cover slip," he said.  

Test method materials under $100

The new method is also relatively simple and inexpensive — not counting equipment, the cost of materials is only about $100.

The research, however, is still in the early stages, and Montagnes says it's still a "big assumption" whether the protozoa will work as an appropriate alternative to human cells.

"It would have to be compared to real animal testing and to, I would suggest, these epidemiological studies where we’re looking at people [who have used the cosmetics],” he said.

Montages says he also wants to look into developing molecular biological techniques that look at how cosmetics affect genes, metabolisms or proteins of cells.

He is hoping to work with cosmetic companies or other groups to continue the research into alternatives to animal testing.

"When you can develop a simpler and cheaper alternative, there is really no need to test cosmetics on animals,” Montagnes said in the release.