Information about animal testing

We still do not understand many of the processes in the human body, or how various structures function, and their extremely complex interaction. Individual processes can actually be studied in isolation in a living organism. But the specific interactions between the individual organs, cells and cellular building blocks can only be studied in a living animal. Comparative examination in different types of animal often gives rise to entirely new insights. This is why basic research also depends on animal testing. The basic research of today is the foundation of the medically-applied research of tomorrow. At the same time, applied research in turn gives rise to new questions that feed into basic research. In other words: basic research and applied research are mutually dependent and lead to progress in practical medicine. The number of laboratory animals used in research is only 0.5 percent of all the animals that are killed each year in Germany. The other 99.5 percent serve our need for nutrition.

The treatment and cure of many diseases that were previously fatal is a matter of course for us today. It was only thanks to animal testing that antibiotics, vaccines against diseases such as polio, and insulin for people who suffer diabetes could be developed. Around 80 percent of children who develop leukemia can be healed nowadays. The treatments developed to fight this malignant disease came to us partly thanks to animal testing. It is impossible to imagine where we would be today with the treatment of cardiovascular diseases, all kinds of cancer, AIDS, as well as in surgery, without animal testing. Millions of patients benefit from this research every day.

The importance of animal testing to medical progress can be seen in the award of Nobel prizes for physiology and medicine. Since 1900 the Nobel prize for physiology and medicine has been awarded about 70 times to researchers whose groundbreaking discoveries were not least made by means of animal testing. The list stretches from the discovery of insulin and penicillin through to today’s AIDS treatments and discoveries about how the immune system or the brain function.

Domestic and wild animals as well as productive livestock all benefit from animal testing, and the knowledge and products it gives rise to: antibiotics, vaccines, narcotics and painkillers are just a few of many examples. Thanks to a vaccine which was originally developed in monkeys, it has been possible to almost eradicate polio. Today, the same vaccine also protects chimpanzees in the wild from this disease. In addition, medicines and vaccines have been developed that benefit animals, sometimes exclusively, e.g. those against distemper, sometimes as well as humans, e.g. those against rabies. The vaccines against Ebola developed in rhesus monkeys also promise to protect the highly-endangered remaining population of West African gorillas.

The components of body cells and the biochemical mechanisms underlying vital processes bear great similarities with humans in various animal species. Molecular genetics can show that all organisms living today have the same origins; the genes that are responsible for the composition of the body and that have modified over time make up the material basis for the evolution of life forms through each geological era. These similarities make it possible to compare human genes and metabolic processes with those of bacteria, fungi and yeasts. Therefore, scientific findings with regard to interventions in the general metabolic pathways can in principle be assumed to be transferable from microorganisms to animals and humans.

Body functions are however far more complicated in more highly developed animals and in humans than they are in more basic organisms, since they arise from a variety of specialized cell types and organs. For instance, an active substance in the liver may have the desired effect, but be chemically altered by the liver cells so that a compound that is harmful to the central nervous system is produced. This shows that the transfer of reaction modes from cell bonds to the entire organism can be extremely difficult. This is why it is always necessary to conduct studies on the entire organism as well as studies at a cellular level (complementary methods). The similarities of cell and organ functions in mammals allow one to assume that they are generally transferable between animal and human. This fundamental assumption applies to both the desired effects of a substance and its harmful and toxic effects. Animal testing makes it possible to predict the desired effects and roughly 70 percent of the undesired effects on humans. One example of this is acetylsalicylic acid (the active substance in the painkiller Aspirin®). This is an analgesic in rats and humans, but in both ingestion can lead to an increased tendency to bleed. The transferability of results from animals to humans also works in reverse: pharmaceuticals that are successfully used for the treatment of humans can also be used for pets.

Alternative methods are not only welcome, valuable and used wherever possible in biomedical research, but also continue to be developed. However, it would be naive to believe that they will make animal testing unnecessary in biomedical research. Animal testing is necessary when physiological connections and their disorders in the body have to be clarified. This includes studies of the central nervous system and the processing of sensory stimuli, the interaction of the circulatory system, the digestive system, the hormonal system, the immune system and the principles of behavior. When considering whether to approve animal testing, the authorities check whether the trial is indispensable or whether the envisaged information can be obtained without the use of animals.

Alternative methods are ideally processes that dispense completely with the use of animals. Here, this is mainly work with cell lines. This is in fact an ideal – since the complexity of an organism, i.e. the interaction of organs and tissue, cannot be completely replaced with artificial systems. Experimental methods outside the organism, in vitro (literally “in the glass”, i.e. in test tubes) processes, already play a major part in research and research funding. But despite all the progress in this area, these processes cannot replace the intact organism, and its reactions must in the end be clarified in vivo (literally “in life”), i.e. in animal trials. In any case, animals have to be killed for the production of organ and cell cultures. To cultivate cell lines, calf serum from animals for slaughter is often needed as a nutrient to stimulate division, growth and differentiation of the cells.

As well as cell lines, computer simulations can also complement animal testing. These are used in biomedical research to map hypotheses about vital processes and test them using theoretical models. This technology is often used in neurobiology to depict functions of the central nervous system. However, in the end the outcomes of the simulation have to be checked in animal trials. Computer simulations are only possible when we already have information about the system that needs mapping, which can be ‘fed’ to the computer. Until now it has not been possible to obtain this information in any other way than trials in the living organism. In addition, every computer simulation has to be simplified because otherwise it would fail simply when confronted with the complexity of an individual cell. Yet the human brain does not consist of one nerve cell but of 86 billion with up to 1000 interlinking connections, which in turn are networked with numerous individual contact points. It is the most complex structure we know.

Researchers, vets and animal keepers do everything they can to minimize pain and suffering in the laboratory. Many of the animal tests, such as observing behavior or collecting tissue samples from dead animals, do not involve any pain or discomfort. Nevertheless, there are experiments that involve pain or discomfort for laboratory animals, when the nature of the experiment make this unavoidable. In these cases we take every effort to eliminate the pain or at least to alleviate it as far as possible, for example by use of suitable anesthetic and analgesia during and after operations. The researchers do everything they can to minimize any suffering on the part of the animals they use in research, and where it is unavoidable, they take every possible measure to keep this suffering to an absolute minimum.

We are very aware of the great ethical responsibility that is associated with animal testing in basic biological and medical research. All the animal testing that takes place here is always carefully checked in advance by the committee on animal experimentation and approved by the relevant authorities.

Everyone who works with animals in the laboratory takes care of their welfare. There are numerous professions that actively contribute to the wellbeing of laboratory animals: animal keepers, technicians, specialist vets and scientists. The animals are treated with compassion and respect by the professionals who are in charge of their daily physical and mental needs. Animals are kept at University of Tübingen research institutes with due consideration for all the provisions of animal welfare legislation and international treaties. Many scientific experiments involve scientists at the university in studying the normal behavior of animals. This observation absolutely depends on the focused participation of healthy, happy animals.

Science relies on critical discourse and that also means hearing different points of view. Scientific models such as the theory of relativity, the big bang theory or psychoanalysis were subject to heated debate, in some cases lasting decades. And scientists are not all of the same opinion on the use of laboratory animals. So animal rights activists like to cite individual scientists who express doubt about the validity of results obtained by animal testing. Statements like these are often seen by those who oppose testing on animals as evidence that it is pointless.

Yet this overlooks the fact that the vast majority of scientists working in basic biomedical research regard the validity of animal testing as beyond doubt. These researchers are nonetheless also aware that the results of animal testing cannot always be transferred to humans one-to-one. The validity of animal testing is – like that of any other scientific experiment – always limited and has to be complemented with other approaches and scrutinized. So animal testing will always be just one building block of science, even if an indispensable one.

The human brain consists of around 86 billion (10⁹) nerve cells with around 86 trillion (10¹²) connections. This makes our brain not only the most complex but also by far the most complicated organ that has arisen over the course of evolution. Unlike all other organs, it is not possible to ascribe specific functions to particular areas of the brain. Rather, it is the interaction of different areas of the brain, nerve cells and the networks that they form that produce the capacity of the human brain. These few lines may help to start to explain the scale of the challenge for scientists who are studying neurological diseases such as Alzheimer’s, epilepsy, Parkinson’s or multiple sclerosis. The diseases that can affect the brain are almost as complex as the brain itself. So it is correspondingly difficult to understand their mechanisms.

Nevertheless, the fact that initial successes in the fight against various diseases of the brain and sensory organs have almost always been made on the basis of animal testing cannot be ignored. A range of new medicines for the treatment of multiple sclerosis offering greater effectiveness has now been developed and licensed. Others are undergoing clinical trials. Parkinson’s disease can be alleviated significantly over many years thanks to medications. All these medicinal therapies are based on discoveries obtained through animal experiments. A significant step forward in the treatment of Parkinson’s that has been made recently, deep brain stimulation (DBS), was largely developed in experiments on monkeys. This new form of treatment is now being applied successfully in more than 100,000 patients worldwide. We also understand certain forms of epilepsy better thanks to animal testing. For instance, researchers in Tübingen were recently able to demonstrate that febrile convulsions, which are a great source of worry in infants, are due to a genetic variation. The path from a discovery to treatment is frequently very long. In recent years, based on more than one hundred years of basic research including on animals, neuroscientists have been able to develop the cochlea implant, which can enable individuals who are completely deaf to comprehend speech.