Testing makeup like mascara and lipstick on animals has long been the pariah of the cosmetics industry.
But now, thanks to tiny organisms called protozoa, cosmetic testing on live animals could end.
Scientists at the University of Liverpool in England found that ciliated protozoa have the ability to detect harmful matter in the environment, Live Science reported. Their findings were published in the International Journal of Cosmetic Sciences.
Protozoa are traditionally studied and tested to understand how things might work in other organisms.
"Protozoa are excellent model organisms," protozoologist David Montagnes from the university's Institute of Integrative Biology told Live Science. "They have been used for over 100 years as models, but we need to go to back and take advantage of them."
Montagnes, along with university undergraduate Haley Thomason, randomly picked six commercial brands of mascara and tested how the protozoa reacted when exposed to them.
A thin layer of each mascara was placed onto a microscope cover slip, which were then placed into compartments that contained protozoa. The scientists made sure to use a type of protozoa with a similar genetic structure to humans, Live Science reported.
Montagnes and Thompson then monitored the protozoa's growth rate. The growth rate of the six protozoa populations depended on the mascara's toxicity and the amount used. Some of the protozoa samples were killed entirely by the mascara, while others were not affected.
This results offer a quick and inexpensive way to show how the mascara brands differ. In theory, because protozoa and humans have a similar genetic structure, the study could work on cosmetic testing for humans.
"Are those differences related to something that's going to affect humans? Since both of the cells that we used are eukaryotic cells, and we're made up of eukaryotic cells, you would expect that there would be some correlation there," Montagnes said, Live Science reported.
For example, the protozoa test could replace the Draize test, a form of testing where a cosmetic is applied to the eyes of an albino rabbit.
Toxicologist Frank Barlie from St. John's University College of Pharmacy and Health Sciences said using the protozoa to test a wider range of makeup would increase the credibility of the results.
"That you can say the test is more sensitive than, or as sensitive as, using rabbits or guinea pigs. That's part of the validation process. If some laboratories decide that this test might be very easy [to conduct], inexpensive and easy to set up, then it will promote itself," Barlie said, Live Science reported.
