The Immune System and Pain
At one point, scientists mostly focused on the role of nerves in controlling and conveying pain sensations, but more recent research has revealed that the immune system has an important role to play in mediating pain sensations. That’s where this difference in pain experience was discovered.
In 2015, researchers from the University of Alabama at Birmingham (UAB) discovered that male mice had a pain experience mediated by immune cells called microglia. These immune cells respond to inflammation or nerve damage by changing shape and releasing chemicals that amplify the intensity of pain signals in the spinal column. The activity of these microglia is moderated by testosterone levels.
Researchers then found that, as expected, a non-testosterone system was used in female mice. Female mice used different immune cells, T-cells, to perform the same role. In some situations, such as when there was an excessive amount of testosterone available, female mice would use the microglia-related system.
Further research has confirmed not only this difference in neuroimmune pain reception but that it remains a promising direction for sex-specific treatments for chronic pain, an important alternative to treatment with opioids, which remains dangerous.