Top 7 Factors for Good Experimental Practice
“The validity of an experiment is directly related to the attention paid to and time spent on preparation prior to the experiment.”
A bold statement, but from my years of working with both more and less experienced scientists in addition of my own years in the lab, I have learned that doing your homework pays off. This is why today I’m going suggest several points to consider when designing your experiments. Some are more obvious than others; several are relatively easy to implement, and they all contribute to the quality of your research. This is by no means a complete list or in order of importance, but I hope that this blog will prompt you to think once or twice that ‘I didn’t think of that before’ and you will give it consideration when preparing your next project.
- Choose an appropriate research model and experimental design to answer your hypothesis. For large animal experiments, we have dedicated an earlier blog trilogy. For rodent studies, especially working with transgenic models, there is more to pay attention to. When creating a transgenic, we don’t know where the transgenic construct is built in the genome. This means that the construct can disrupt an important endogenous gene. The non-affected allele should make up for this, however this does not always avoid problems (lethality, breeding issues, etc.). So make sure that the strain you work with or have created yourself is not only genotyped but also phenotyped properly, making you aware of any biological abnormalities. This leads me to my second point.
- Stay in touch with your animal caretakers. They are your eyes and ears in the animal facility and look daily over your colony. Large animal wellbeing is easier to monitor compared to rodent wellbeing. Rodents are prey animals in nature and, as a result, they will try not to show disease or pain as this would make them more vulnerable. Feeding and grooming behavior is important to monitor as it will be influenced prior to other observations. When you see that a rodent is not feeling well, it is truly suffering.
- Know how to perform your experiment in the best manner possible. In animal experiments, this includes performing your surgeries with as little damage to the tissues and thus, to the animal as possible. Choose your anesthesia and any post-operative analgesia wisely, monitor body temperature and fluid loss during surgical procedures. None of us were born a surgeon, although some have more steady hands than others, so get trained! Search for videos of the procedure you are going to perform. Attend a surgical workshop live or online, to become an expert in your procedure of interest. Read up on available protocols. Not only will you obtain higher quality data, it is the only ethical thing to do when you can’t replace your animal experiments with a suitable alternative. Depending on the local rules and laws, there are options to practice on surplus animals or join fellow researchers at the end of their experimental day, so as few as possible lives will be sacrificed.
- This last point brings me to an important part of your preparations: Power calculation and sample size. A science on its own! A “power analysis” is often used to determine sample size. The use of too many animals (or other experimental units) wastes animals, money, time and effort, and it is unethical. But if too few animals are used the experiment may lack power and miss a scientifically important response to the treatment. This also wastes resources and could have serious consequences, particularly in safety assessment. So make sure you seek support from a statistician if needed.
- Know how your measuring device works. How does the technology work and what can influence the technology. What is best practice to use it? But also, what are its limitations? Take advantage of the knowledge and experience of application specialists and experienced colleagues. For Transonic’s research equipment, we not only have an extensive database of protocols, tech notes and workbooks. We also have our research application specialists and product managers available to help you when needed. We are happy to be ‘on call’ during your experiments, so you have back-up support when needed.
- Make sure you have everything you might possibly need readily available before you start an experiment. Go over every step on your experiment, anticipating any support material that might be necessary. This goes from anesthesia (a bottle of isoflurane for example) to bleeding mitigation agents, such as gel foam and ultimately euthanasia agents. Being prepared gives you the best chance to carry on a viable experiment and also perform an expedited euthanasia procedure in conformity with the highest ethical standards.
- Choose quality of data over quantity of data. Animal lives are precious and you should always aim not to waste any tissue or omit to collect relevant data that is available. However, there should be a balance between collecting all that you can and collecting the best way possible. Each technique and type of data comes with their own requirements. Some can be combined in one experiment, and some are just not reconcilable. Be critical! What is a ‘must have’ to answer the hypothesis and which data or tissue is ‘nice to collect’. This may mean that you have to use separate animals for separate end-points. This is not ideal, but it is always better to be able to collect meaningful data, than to take a short cut and have inconclusive results.
It is always a good idea to reflect occasionally on the routines in the lab. Some of the above suggestions might seem redundant, and you can check them off the list easily. Great! However, if you catch yourself thinking, ‘I do this because this is how my colleague does things’, you may want to give it a second thought. The right way that works for your colleague does not automatically mean it is the preferred way for you and your experiments. We all know the ‘this is how it always has been done’. If we would stick to that premise, typewriters would still be in fashion and we would type papers by candle light. At Transonic we have a team with more than three decades of lab experience, in addition we work with and learn from all our customers. Sometimes an outsider has a fresh view on how routines have become routines, and a different set of eyes may give you the opportunity to create new and better routines. Feel free to reach out. We are here to help.