Gender of Researcher Found to Affect Stress Response in Mice
And that could sway scientific findings generally, researchers say
TUESDAY, April 29, 2014 (HealthDay News) -- The scent of male researchers, but not females, triggers stress in lab mice and rats -- stress that might alter the findings of experiments, according to a study published online April 28 in Nature Methods.
Robert Sorge, Ph.D., and colleagues at McGill University in Montreal, found that when men were in the lab, mice and rats had a stress response equal to being restrained for 15 minutes or being forced to swim for three minutes. This stress made both male and female rodents less sensitive to pain and caused them to respond differently in behavioral tests.
On the other hand, Sorge and colleagues found that female researchers caused no stress reaction in the lab animals. In order to confirm that this stress response was related to scent, the researchers exposed mice to cotton T-shirts that had been worn by male and female researchers. The stress reaction was the same as that caused by the presence of researchers. Further investigation revealed that the mice were stressed by pheromones, which men emit from their armpits at higher levels than women.
The findings could have real implications for rodent-based research everywhere, the Canadian team said. For one thing, they point out that scientists often find it difficult to replicate findings from animal research, which has led to concerns over the reliability of these studies. However, "our findings suggest that one major reason for lack of replication of animal studies is the gender of the experimenter -- a factor that's not currently stated in the methods sections of published papers," Sorge said in a statement.