Rats (and mice) are often the animals of choice to try and model human conditions, treatment and body functions - even though we know that using animals to try and model people fails over 90% of the time.
Mice and rats are commonly used due to their small size, low maintenance (i.e., they are easy to house and care for), short life cycle, and ability to breed quickly (allowing large numbers to be generated for studies).
They also share many of our genes.1 However, that's not surprising. Even cats share many of our genes.2
Rats are used is some of the most gruesome experiments that involve things like force-feeding, poisoning, oxygen deprivation and invasive surgery.
Rats in NZ have been used for:
- Drug research, including safety and efficiency testing.
- Teaching purposes in schools, mainly dissections.
- Investigating ways of killing wild rats. (i.e., research into effective poisons and traps).
- Medical research, including research into the development of severe diseases (i.e., stroke, diabetes, cancer), modelling neurological disorders (i.e., Schizophrenia, Autism), modelling mood disorders (i.e., example, anxiety, and depression) and research into tinnitus.
- Drug addiction research including research into the development and suppression of addictions and the impacts of drug use.
- Basic biological research, including research into digestion, aging, nerve damage, obesity and how the brain functions.
Places that use rats for science in NZ include crown research institutes, private companies and universities. In fact, most universities have their own breeding colonies. Otago University states on its website that they have a dedicated rat testing room in the Behavioural Phenotyping Unit.3
Rats used for science in NZ are sourced from breeding units, public or commercial sources, the wild (captured) and they are imported from overseas.
Discover real-life examples of how rats have been used in NZ below!
Studying the effects of obesity and mussel powder on bone health
Rats were kept alone and fed different diets containing normal or high amounts of fat or sugar. Some were supplemented with Greenshell mussel powder. X-rays were done, and some rats' ovaries were removed. Ultimately, all were killed by bleeding them out.
Testing the safety of a probiotic supplement
Rats were force-fed with a probiotic solution or control solution. After two weeks, they were killed for dissection.
Studying food intake in an autism "model"
Pregnant rats were injected to cause autism-like symptoms in their babies. The male babies were put through behavioural tests with control animals as well as a feeding study. Some were fasted for 16 hours and killed by flushing their hearts.
Trying to study schizophrenia
Half of a group of pregnant rats were injected to affect their babies' brain development. Some pups were allowed to grow up to test their behaviour.
Testing the effect of diabetes on pregnancy hormones
Rats were anaesthetised, and their brain was accessed through the mouth to measure reactions to stimulation. In the end, all rats were killed.
Testing diabetic rats’ hearts
Genetically diabetic fat rats and their lean littermates were anaesthetised. Ultrasound images were made from their hearts. All were killed and dissected.
Testing a connection between tinnitus and brain function
Rats were anaesthetised and one ear was damaged with noise. Rats were taught that silence meant they would get electric shocks and freeze in fear. This was a test for tinnitus.
Studying the communication between inner ear and brain
Rats were anaesthetised, and their inner ear was partly removed, before parts of their brains were stimulated with wire electrodes. Reactions of the rat's eyes and brain were recorded. In the end, all rats were killed.
Testing if a brain region controls memory
Some rats had their brains surgically heat-damaged. Electrodes were implanted to monitor brain activity and to stimulate the damaged parts with light. Rats then had to re-perform memory tests to see the impact before all were killed.
Releasing a rat family into the wild to see where they go
A wild-caught rat was mated, fed a fluorescent dye, and released again with her pups. Traps, tunnels, and cameras were set up to track and eventually recapture the animals, which did not work 100%.
Testing a rat poison that is unattractive for dogs
Rats were kept in small cages and fasted overnight. Then, they were given two food trays. One of them was scented with lion, tiger, or dog faeces.
Comparing digestion of sheep versus cow milk yoghurt
Rats were fed cow milk, sheep milk, cow yoghurt or sheep yoghurt for two weeks. They were gassed with CO2 before their necks were broken.
Testing medication after heart attack
Rats were anaesthetised, and their hearts were exposed. A heart attack was simulated by blocking an artery. Some had dye injected into their brains, and some were injected with test drugs. All animals were killed.
Comparing digestion of sheep versus cow milk
Rats were fed a test diet containing beef protein and received cow milk or sheep milk instead of drinking water. After 28 days, all were killed.
Testing a medicine against drug addiction
Mice's tails were dunked in hot water. Rats were put through cycles of drug-seeking and withdrawal using self-injection of cocaine. Other rats were injected, and their behaviour was tested (with the notorious Forces Swim Test, among others).
Studying teen binge drinking
Young rats were force-fed alcohol repeatedly. Each time, blood samples were taken, and some were killed to take their brains after each alcohol day. The remaining rats were put through behavioural tests a few months later.
