Man flu or myth? Why we study mice of different genders to understand illness
The term man flu is typically used in jest; perhaps in conversation between two women joking about how their husbands react to illness. For others, the phrase may be completely new. However, recently it has risen to the surface enough in mainstream media and water cooler discussions to draw interest from researchers.
Researchers at the University of Ottawa recently set out to essentially answer the question, do identical infections actually make males more miserable than females?The study involved injecting lab mice with molecules from bacteria. They found at the onset of infection the male mice’s body temperature fell more than females’ did. An article in Stat extrapolated this fit with the idea of the man flu.
Ryan Langlois, Assistant Professor in the Department of Microbiology and Immunology at the University of Minnesota, did not make the same connections as the article. He fits into the latter category of people as far as man flu is concern; he’s never heard of it. However, Langlois is no stranger to discussions over something’s scientific worth or existence. He’s made made a living searching for answers based in science. And that is what intrigues him about what researchers found in that study.
“We know most diseases respond differently to males than they do to females,” said Langlois. “This finding shows why it’s important to use both male and female mice.”
The use of both gender of mice is a newer standard; Langlois says it’s not something labs always paid close attention to in the past but changes in the NIH requirements require both gender mice to be used – and to record the sex every animal. For a long time, many preclinical studies used only male mice. The reason, to put it simply, was to simplify things, create less variation.
While he can’t speak to if the Ottawa study gives men justification to complain more when they feel ill or not, Langlois believes this new model of tracking mice and testing both genders can give a better translation into human diseases.
Right now, it’s too early to tell if that’s the case. The consideration of sex as a biological variable in NIH-funded research started in 2015. The catalyst for this change included the need to improve the understanding of health and disease in men and women, and when sex is not included as a biological variable, transparency and generalizability of the research findings may be compromised, or in the very least, undetermined.
“What’s encouraging about this, is knowing the government cares our research is accurate, and that things are now moving in the right direction,” said Langlois.