‘Using hundreds of laboratory animals for research is rather outdated’, says Li, who received his Ph.D. on Friday for his research into the absorption of medicine in the intestines. As such, he wanted to use a test animal-saving method in his research and happened upon an existing technique which is rarely practiced: the so-called precision-cut tissue slice technique.

Sharp knife

With a sharp surgical knife, Li cut the intestines of the rat into thin slices. As the intestines are hollow, he first had to spray the intestines with a special agarose gel. The gel is liquid at 40 degrees, but becomes solid at low temperatures. Before Li cut the intestines into slices, he placed them into a cold buffer bath for a little while. The whole process yielded hundreds of pieces of intestine with which the pharmacist could carry out many different experiments without using too many laboratory animals.

Although this technique has been around for a while, Li is the first to use it for transport research. ‘I looked at the way in which medicines are transported through the intestinal wall’, he explains. ‘This is important because by doing this we can understand the absorption of medicines in humans better.’

Li’s results provide greater clarity about the transport processes in the intestines, and they also show the possibilities of the precision-cut technique. ‘Up until this point, researchers only used this technique to study metabolism or toxicity’, says Li. ‘Maybe it could also be used for other research studies.’

Sharing test animals

To be fair, you do still have to use laboratory animals with Li’s method. The number of animals, however, is considerably lower than in the past because you can do multiple experiments on one rat using this technique. Li’s colleagues are using the same technique to research the lungs, liver and kidneys of the rat. Where you would traditionally have needed hundreds of rats to carry out all of these experiments, researchers are now able to get all the information they need from just one rat.

The pharmacist is certainly hoping for a future without laboratory animals, but does not see this happening in the next ten, or even twenty, years. ‘The FDA (the American government agency which checks the compliance of medicines to the set standards, ed.) maintains that all medicines have to be tested on laboratory animals’, Li says with a sigh. ‘Methods which spare animals, such as computer simulations or precision-cut-techniques, are not yet recognised in America as replacements for laboratory animal experiments. We have to change this if we want everyone to step away from using laboratory animals.’