Microglia-mediated chronic psoriatic itch induced by imiquimod

Activation of glial cells has been shown to play an important role in chronic itch. However, whether glial cells play an important role in the development of psoriasis-induced chronic itch has not been fully elucidated. This study investigated the role of spinal glial cells in psoriasis-induced chronic itch. To develop a mouse model of psoriasis-induce chronic itch, we used 5% imiquimod cream to receive a daily topical application on the shaved back skin for seven consecutive days. The results showed that the expression of microglial marker ionized calcium binding adaptor molecule-1 was significantly increased after 5% imiquimod treatment in cervical spinal cord dorsal horn (C3–C4), and the intrathecal microglial inhibitor minocycline or PLX5622 diet suppressed both spontaneous itch and microglial activation. Furthermore, we found that the number of scratches and alloknesis score in female mice was significantly greater than in male mice after 5% imiquimod treatment. Our results indicate that microglia mediate chronic psoriatic itch induced by imiquimod.