Neuropathic pain is a specific type of pain that results from injury to a nerve fibre or part of the nervous system. Due to unique qualities of nerves, neuropathic pain often becomes chronic and a long-term economic and societal challenge. The prevalence of neuropathic pain in the clinical population is 5% in men and 8% in women, but pre- clinical animal research has focused mainly on male models. Microglia, immune cells in the nervous system, are the main mediators of the neuropathic pain pathway in males and increase pain signaling to the brain. Recent initiatives to include female animals in pre-clinical research revealed that microglia are not necessary to cause female neuropathic pain.
The aim of this literature search was to examine where the pain pathway differs in males and females and where it converges back together to cause, what both sexes know as neuropathic pain. The results confirm that blocking microglia was not sufficient to alleviate pain in females with nerve injury, but pain was alleviated in animals in which microglia and T-cells were deleted. The present state of knowledge suggests that T-cells are the cells contributing to central sensitisation in females, but the site at which they interfere is still to be determined. More complex investigation of the role of T-cells in pain and analgesia will be beneficial to clarify how they can interfere with pain treatments, and help us design new, more effective treatments for females and males suffering with chronic pain.