As the search to find testing methods without the use of animals continues, a group of scientists in Sweden have developed a unique test method that enables graded results to be obtained using cultured skin cells.
The scientists developed the new method for testing allergenic substances without experimental animals at the University of Gothenburg in Sweden as they were researching methods to test cosmetic products in order to prevent the development of contact allergy, something that affects 20 percent of the population in the western world.
“We have made several discoveries about the mechanism behind contact allergy, one of which is that allergenic substances react with keratin 5 and 14 in the skin,” explains Sofia Andersson from the Department of Chemistry at the university.
“The skin cells form what are known as “blebs” when exposed to allergenic substances, and this can be used to test whether a substance is allergenic.”
Metals such as nickel and substances in perfume and preservatives are among the most common allergenic substances, often in skin lotions and make up. It can be difficult to avoid contact with these allergens if the substance is present in many different products.
With the new test method cultured skin cells are exposed to substances for 24 hours and then photographed. The number of cells with ‘blebs’ (irregular bulges in the plasma membrane) is then counted.
“The greater the number of blebbing cells, the more powerful is the allergenic potential of the substance. Thus, our new test has the potential to give a graded reply: it can quite simply determine whether an allergenic substance is extremely, strongly, moderately or weakly allergenic”, says Andersson.
The results can then be used to determine safe concentrations of substances in products that are used in contact with the skin. The scientists are now working to develop the test and the analysis method.
Searching for alternatives
European legislation restricts animal testing within the cosmetic industries, and companies are increasingly looking at alternative systems to ensure that their products are safe to use.
It is not the first time Sweden has introduced an alternative to animal testing either. Researchers from Lund University found a cell-based alternative to animal testing that could be used to detect allergies and the strength of the response in cosmetics products, in mid-2011.
Whilst still in the early stages of development also, the research demonstrated that the response of laboratory grown human cells could be used to classify chemicals as sensitising, or non-sensitising, and can even predict the strength of allergic response.