Chronic pain and neuroinflammation

•Central sensitization is based on a two-way interaction between the nervous system and immune system represented by the microglia.•Activation of the microglia or microgliosis and activation of astrocytes lead to hypersensitivity and neuronal plasticity in the central nervous system.•Growth factors (BDNF), cytokines (IL-1, TNF, IL-6) and chemokines play a major part in this neuroinflammation.•Microgliosis can extend to certain supraspinal structures involved in pain modulation and the emotional and cognitive aspects of pain.