By Monika Piotrowska.

Before the pandemic, an Italian colleague of mine from the biology department and his Polish wife would host elegant gatherings to celebrate the birthdays of their trilingual children. The adults would mingle around a large table that displayed an impressive array of gourmet delicacies while engaging in lively conversations. Occasionally we would all pause to listen to an impromptu musical performance by our hosts or their guests and take a moment to discreetly ensure the mayhem of our children was being kept (more or less) in check.

During one of these gatherings, I met a colleague from the psychology department who told me about his research. He was exploring the connection between female hormones and depression. Intrigued, I asked a series of questions and was surprised to learn that his research subjects were mice, not women. “But how do you know if a mouse is depressed?” I asked. He told me researchers determine whether a mouse is depressed by putting the mouse in a tank of water (from which it cannot escape) and observing how long it will swim. A mouse that stops swimming earlier than its cohorts—and starts floating—is considered depressed. What a bizarre and interesting way to measure depression, I thought. A mouse that falls into despair upon realizing the pointlessness of its struggle.

I wanted to know more about this test (which by the way is called the Forced Swim Test), hence I arranged a few meetings with my new acquaintance. At first, I was interested in exploring alternative interpretations of the test itself. Why do some mice stop swimming earlier than others? Are they more depressed or is something else going on? But then my interest shifted to the test subjects themselves—i.e., the mice used in the experiments. I knew that depression, along with most human diseases, was studied on mice and rats, but what I didn’t know is that animal research on depression has been done almost exclusively on male rodents. That struck me as odd considering that depression occurs much more frequently among women than men—by an almost 2:1 ratio. Were female rodents being excluded from animal trials?

Indeed, female rodents have been systematically excluded from such studies. Until just a few years ago, no major funding agency required grant recipients to use both sexes in animal research. Females were routinely excluded because their hormonal cycle was viewed as a potential source of variability. If relying exclusively on male rodents weren’t worrisome enough, I subsequently learned that most laboratories also rely on a single genetic strain of mice, called Black-6. Learning more about the extent to which animal experiments have been homogenized, and the ways in which excessive homogenization can hinder translation, led me to write the paper published in the Journal of Medical Ethics.

The paper is a contribution to the growing body of literature on how to improve translation from research on nonhuman animals to human patients. What sets my paper apart from the others in this area is that rather than targeting scientists, my recommendations are directed towards the review procedures and protocols of Institutional Animal Care and Use Committees (IACUCs). The paper employs an argument by analogy to make its case. The idea depends on noticing that underrepresentation in research involving human subjects has been a contributing factor to the translation crisis, and that Institutional Review Committees (IRBs) have been urged to address this issue. Similarly, I contend that animal ethics committees can adopt a comparable approach. Just as IRBs bear a fundamental responsibility to consider diversity and inclusion in human research, I argue that IACUCs also bear a similar responsibility in animal research. By implementing initiatives focused on diversity and inclusion in nonhuman research, we can strive to minimize unnecessary animal distress, prevent the sacrifice of animal lives for the sake of flawed research, and improve the translatability of data from animal research subjects to human beings in need of help.

Paper title: Diversity and inclusion for rodents: how animal ethics committees can help improve translation

Author: Monika Piotrowska

Affiliation: Philosophy, University at Albany, State University of New York, Albany, New York, USA

Competing interests: None declared