By Rebecca Morelle
Science reporter, BBC News
"It's a question I get asked a lot," says Vicky Robinson.
Scientists say animal experimentation is vital
"And unfortunately we are a long, long, long way off. I would love to be sat here saying within the next year or so, or within the foreseeable future, but I think one has to be realistic."
The chief executive of the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) is considering at what point science might finally be able to give up using animals for research.
In the UK, just under 2.9 million animals were used in research in 2005. Uses range from basic biological research, to studying diseases and developing news medicines, to assessing the safety of chemicals.
While some groups would like animal experimentation to stop immediately, either on ethical grounds or because they question the scientific validity of such experimentation, the vast majority of the scientific community believes that research using animals is vital.
"Everybody knows that animals are not perfect models, they are just the best models that we have at the moment," explains Professor Chris Higgins, from the Medical Research Council.
"If there were better models then of course one would use them, but they often provide the only way that we can get at certain information."
But what exactly is the scientific community doing to find these better models or to limit the numbers of animals used, so as to move us closer towards the animal-free laboratory?
Currently, efforts are guided by a set of principles known as the "three Rs":
In the UK, the Home Office requires any applicant for an animal licence to demonstrate that they have and will implement this principle.
- Reducing the number of animals used to a minimum
- Refining any experiments so they cause as little suffering as possible
- Replacing the use of animals with alternatives where possible
But according to a 2002 House of Lords report on animal research, this was not enough, and it recommended that the scientific community needed a central body to foster and promote efforts in the three Rs. The NC3Rs was the result.
"We want to raise the kudos associated with the three Rs in the scientific community, and we also want to provide better access to information," Dr Robinson explains.
As animals are essentially used in experiments to model how the human body would react if, for example, a drug were given or a chemical inhaled - to replace the animal would require finding another means to "see" what is going on in the body.
Computer modelling - producing virtual cells, organs or even whole organisms - has been hailed by some as the likeliest contender for cutting animal use.
Indeed, some progress has been made. There are currently computer models of pancreatic cells, various cells and tissues in the lung, kidney function, liver function, the musculoskeletal system, and neuronal systems.
But perhaps one of the most advanced models is the virtual heart, created by Professor Denis Noble of Oxford University.
Looking at a screen, you can see it beat, have a heart attack, and reveal the effects of chemicals on it, making it useful for screening drugs.
"With life, we are dealing with about 30,000 elements interacting - that's the number of genes we think there are. Goodness knows how many proteins and bits of RNA there are to add into this mix," says Professor Noble.
"Computation simulation and its mathematic basis come in because you need it for understanding."
But, he points out, it and other models are still a long way off an exact organ replica.
"Some people say to me when they see the virtual heart beating on the screen, 'what is there left to do, it looks so realistic'.
"Yes, it does look realistic in terms of reconstructing a heart attack, for example, but we suspect we have modelled only about 2% of the genes and proteins involved in that activity and there are 98% still to go."
But if computer models still have some way to go, there are other techniques that scientists can employ to make progress in the meantime.
A new way of seeing
"In vitro work is an excellent way of replicating simple systems," says Dr Phil Stephens, a cell biologist from Cardiff University who is working on such a system to screen drugs for leg ulcers.
"It is also very cheap and cost effective. You can grow some cells in a lab and it will cost tens of pounds, as opposed to housing animals under strict conditions that can cost hundreds, if not thousands, of pounds."
But although the systems are getting more and more sophisticated, they do have their limitations, he says.
"I think that replicating a whole animal organism is still a very long way off."
Imaging is another method where scientists can cut the number of animals used still further. Techniques such as MRI and PET scans are enabling scientists to observe what is going in a human body, as a drug is being processed, for example.
"By imaging animals, we can get a lot more information on many fewer animals than we would get through invasive procedures, and of course there is a lot less suffering," says Professor Higgins.
But, says Maggie Jennings from the Royal Society for the Prevention of Cruelty to Animals (RSPCA), it is not just about finding alternatives.
Particularly important for the animal is how to minimise suffering, she says, and small changes to the way an animal is housed can make an enormous difference to their wellbeing.
"The environment is important because animals spend most of the time in a laboratory in their cage or enclosure rather than undergoing procedures."
She says animals like mice should be housed in socially compatible groups, be fed an appropriate diet, and have nesting material and fun tunnels, where they can hide from other animals or people.
But Dr Jennings also points out that although standards of care in the UK are said to be higher than elsewhere, this depends on how you define highest possible standards.
"OK, we have good regulations in the UK, but it is how they are understood, interpreted and implemented and how much effort is put into thinking about refinement and putting it into practice," she explains.
But while progress in the three Rs has, according to some, improved over the last few years, the number of animals used in research continues to rise.
Advances in the field of genetics mean more genetically modified mice are being created and used in the laboratory, and new EU legislation surrounding the safety of chemicals is expected to push animal use higher still.
Vicky Robinson says with this is mind it is even more important that investments are made in finding new ways to replace, reduce and refine animal use.
"It should not just be a one off event where if you are getting a licence you just think about the 3Rs - it should be throughout the programme of research.
"And, of course, many researchers do think about it - but there is thinking about it and also being able to do something about it.
"And to be able to do something about it you often need more money, increased kudos and a will to do something different."