Animal Models of Multiple Sclerosis – Are They Useful?

Animal models of multiple sclerosis are not perfect.  I think that is an important first point to make.  As we still don’t know what causes multiple sclerosis, we can’t replicate the disease exactly in animals.  Instead, we aim to re-create many of the characteristics that we see in MS (such as chronic inflammation, autoimmune attack of myelin, etc) in an animal setting.

The most widely used animal model for multiple sclerosis is experimental autoimmune encephalomyelitis (EAE).  EAE can be investigated in many different animals, however, a large majority of the studies use mice as the organism of choice.  Similarly, there are many different ways of inducing or causing the disease in mice.  The most common method involves injecting mice with parts of myelin proteins, mixed with something to provide additional stimulation to the immune system (called an adjuvant).  Other techniques that are used to create an MS-like disease involve injecting the mice with toxins or viruses known to cause damage to myelin.

There is no doubt that the use of animals in medical research is a controversial topic.  It was heavily publicised in the news earlier in 2017, when it was released that a university in Ireland had used approximately 24,000 rodents in 2016 alone.  This prompted some protesters to suggest that “if the animals don’t suffer, why don’t they [the researchers] volunteer themselves?”

It is important to realise that any research projects that involves the use of animals must be approved after submitting a thorough application to an ethics board.  This requires justification of the numbers of animals being used, as well as how they will be treated during the study and what will happen to them at the completion of the experiments.  Having been involved in research for a number of years, I can say from my personal experiences that scientists who do this sort of work do not particularly enjoy it, and only do it when they believe it is truly necessary for their experiments.

Keeping all of this in mind, it begs the question, are the use of animal models in multiple sclerosis research worthwhile?  There is no doubt that we have learned a lot of useful things about a number of aspects of multiple sclerosis from studies performed in mice.  As well as this, a number of the currently available therapies, such as Gilenya, Tysabri and Copaxone, all started by showing benefits in treating EAE.

In saying that, it is also important to keep in mind that many findings or novel treatment options that are discovered in mouse models of multiple sclerosis do not end up being useful or successful in human trials.  As mentioned earlier, these models just seek to mimic multiple sclerosis, they aren’t exactly the same and these differences can lead to conflicting results.  For this reason, it is incredibly important that we always keep the results of animal studies in perspective.

In the end, I think the subject of the use of animals in medical research is always going to divide the community.  Everyone is entitled to their own opinion and there is certainly no right or wrong answer on this issue.  Regardless of your feelings about the ethical nature of these studies, it is critical that we report the findings of this research in an accurate way and put into context what it may mean for people with multiple sclerosis in the future.