THE EXPERIMENT:

Guinea pigs were used to develop a thermal stress test.¹ Outbred Dunkin-Hartley guinea pigs were sourced from a breeding unit at the University of Otago in Wellington.

Animals used:

Six guinea pigs who were born at full term (i.e., the length of a natural pregnancy).
Four guinea pigs who were purposely born prematurely. Their labour was induced early through repeated injections into the mother.

The guinea pigs were lightly anaesthetised, enough so that “animals were responsive to pain.”

Needle electrodes were used to measure their heart activity, and other devices measured blood pressure, breathing and oxygen saturation.

Probes were put onto their skin where their hair had been removed using hair removal cream.

Their body temperature was also continuously measured via rectal thermometer, pushed 4cm past the anus, and on the skin in four places.

The animals were used in two different treatments.

Treatment one: The guinea pigs were wrapped in a temperature-controlling blanket, which was slowly heated to 44°C, and kept there until the animal's body temperature rose to 41.5°C.

Treatment two: The guinea pigs were wrapped in a temperature-controlling blanket, which was slowly cooled to 15°C, and kept there until the animal's body temperature fell to 34°C.

The paper does not state what happened to the animals afterwards, so we sadly don't know their fate.

The image below is taken directly from the research paper we discovered (reference below), so you can see exactly what this looked like…

The temperatures that the animals were heated or cooled to weren’t random. In fact, how these temperatures were picked uncovers another experiment that was conducted first – referred to as a pilot study.

In the pilot study:

One 35-day-year-old guinea pig was heated to 35°C, 40°C, and 45°C. In the final stage (the highest temperature), their core temperature exceeded recoverable levels, so they were euthanised.

One 35-day-year-old guinea pig was cooled to 30°C, 25°C and 15°C. Cooling resulted in their core temperature dropping below a recoverable level, and the animal was euthanised.

In short, both temperature thresholds were picked after a pilot study, where one pup was heated and another cooled too much, so they had to be killed.

The purpose of this experiment was to try and develop an animal model for thermal stress and use it to design a reproducible method to measure body reactions to thermal stress (while not killing the animals). This guinea pig model is intended to study predisposition for cardiovascular disease, for example, due to preterm birth.

However, we know that there are better ways to find the answers we so desperately need to help ensure better health outcomes for people!

How to study predisposition for cardiovascular disease without animals?

Below are just a few examples of animal-free research that can be used and explored further to help people affected by this disease:

Microfluidic systems could be used for natural organ simulation, disease modelling, drug screening, disease diagnosis and therapy.²
Researchers can mimic the hypoxic stress (low oxygen levels) during a heart attack and study the resulting arrhythmic heartbeat with on-a-chip models. These models can also be used for preclinical drug evaluation.³
We can even study the association between heart disease and ageing.⁴
In silico gene association analysis can reveal a predisposition to coronary artery disease.⁵

So the answers don't lie in our animal friends. They aren't lab tools to be used and disposed of as we please. There is a better way, and it involves using animal-free and human-relevant research methods.

We work to remove the barriers that are preventing the use of such sophisticated animal-free scientific methods, and by supporting NZAVS, you are standing behind this mission!

Note: At NZAVS, it's important that the work we produce is evidence-based, which is why we include references wherever possible. However, it's also crucial that our many fierce supporters know that NZAVS is a non-violent charity, and we seek to make change through peaceful methods. Non-violence to us isn’t just physical, it also includes avoiding verbal and psychological violence.