A lot happens behind closed doors in a science laboratory. There are rows of petri dishes, suction-sealed specimens, vials of this and that, the odd explosion, hypotheses galore from white-dressed humans, and rodents on which to test it all.
Be it rats or mice, these small animals donate their living (and dead) bodies to science. They serve as an avatar for human disease and infection and a gateway to all manner of drugs, treatments and cures. But the realities for rodents, and the scientists responsible for them, are not always rosy.
“I saw my rats every day for eight weeks, including weekends. You don’t necessarily bond with them, but they go from being really afraid of you to really comfortable in your presence,” former honours student Wardah Nasir told Crikey.
Nasir had 26 lab rats to experiment on and care for as part of her research into the prevention and treatment of birth injuries. To make scientific headway, she needed to stimulate birth in rats: “Basically we had to injure the rats by putting a balloon catheter into their vagina. When they were under, I compartmentalised, but after the fact I was always like, ‘Oh my God, these are rats.’ I needed therapy.”
Laboratory-based rodent research is bound by ethical rigour and clear-cut codes, but that doesn’t make it easy for researchers to draw the line at science experiments.
Role of a rodent
Most science takes decades to make it from ideation in a lab to application and uptake in the real world. In between is round after round of experimentation and replication. Phase one is discovery, phase two and three are animal testing — first small (rodents) and then large (something like a sheep) — and finally comes clinical trials.
The appeal of rats and mice is their likeness (physiologically) to humans and their ability to replicate fast. They’re easy to breed, inbreed and crossbreed and in no time at all there are litters galore. They also mature from babies to adults at a rate of knots.
“Eight weeks in a rat is like four years in a human, so you can see a lot of change in a short time,” said Nasir.
Supporting role of a scientist
Researchers working with rodents are bound by the “three Rs”: replacement, reduction and refinement. In short: don’t use rodents you don’t need and care for the rodents you do.
“If you have a massive study and you fall short of statistical significance by two mice, then that experiment is kind of a waste. There needs to be enough mice for viable and publishable results but no more,” said a lab-based infectious disease researcher who spoke to Crikey on condition of anonymity. Confidentiality protocols in their institution prohibited them from speaking freely about the relationship they maintain with their 60-odd mice.
There is a strict harm-reduction regime in place for both the life and death of rodents. Scientists feed them, weigh them (by putting them in a little box that sits on a pair of scales), and check for signs of ill health or out-of-sorts behaviour such as squinted eyes or splayed-back ears.
“I had to do six months of intensive training to learn how to handle and hold these rats without injuring them, how to soothe them, how to look for behavioural cues. All this before I could care for them,” said Nasir.
The intensity of monitoring depends on the experiment and whether or not drugs need to be administered or surgery done, but the general rule of thumb is to check in at the same time each day for consistency.
On a surgical day, Nasir said the check-ins turn hourly: “If the experiment was booked from 9 to 12, I’d go in, say hello to the ladies, pick them up, put them under anaesthesia, make sure they couldn’t feel anything because it’s very invasive, do the experiment, make sure they weren’t in shock, make sure they’re not dead, monitor for two hours, recover them, and monitor for another four hours.”
On top of harm reduction are clear red lines and “ethical endpoints”. If a rodent loses more than 15% of its starting body weight, a scientist is ethically obliged to kill them, irrespective of whether the study has reached its natural end.
Let’s talk feelings
The same scientists that care for these rodents are also responsible for their pain, suffering and timely death. Lab researchers try to compartmentalise and maintain a purely practical approach, but it’s not always easy to juggle these conflicting emotions.
“Performing a procedure like an injection can be distressing because the rodents are awake and sometimes they squeal,” said the infectious diseases researcher.
To inject a rodent, you have to “scruff” it. “Just like a dog or cat, it has flappy skin at the back of its neck. You pinch that flap of skin, turn their head down towards them, pinch their tail with your pinkie so they can’t move, and then you inject them.” As the infectious disease researcher explains, that doesn’t sit well with them.
Death was (at times) described as an easier deal because the process was largely procedural. Gold standard is to cover the cage with a cloth (for the benefit of both scientists and fellow rodents watching on) and gas them with carbon dioxide.
“Once I did lift the cloth and I started crying my eyes out because I saw the last breath it took. It was the first time I saw the life drain out of a living thing. You know they’re not in pain, but that was not a fun time,” said Nasir.
For the infectious disease researcher, most triggering was the bin bag of carcasses. After rodents are declared deceased (done using a toe-pinch test) and they’ve had relevant bodily parts removed (a lot of experiments require post-mortem samples and data), they go into a bin bag that goes into a freezer before being incinerated later.
“You might take the spleen out, sometimes you take the brain out, but all of that feels very procedural. You’re using your muscle memory. When you have the carcasses, that’s when it hits home,” they said.
Post-mortem on relationship with rodents
The life and times of a rodent might be short-lived, but it leaves a mark on the scientists experimenting on them, caring for them, and sending them to the morgue.
Nasir says they gave meaning and purpose to her research. Rather than simply data on slides, the rodents were a reminder that these parts and methods come from somewhere, “from something”.
It’s why she would always give a rat a departing thanks before putting it down: “I would say, ‘Thank you, ladies, for the work you’ve done. Thank you for your contribution to women’s health. You’ve done more than I could ever do’.”
The nameless rats were also given formal acknowledgment in Nasir’s thesis.
Why no names? Because they all look and act the same. Plus, she said it’s a disastrous recipe for attachment.
