The activation of glial cells is involved in the pain and pruritus in allergic contact dermatitis.

BACKGROUND

The activation of glial cells in the central nervous system plays an important role in the neural signaling of chronic pain and pruritus. However, their involvement in the neural signaling of chronic pain and pruritus in ACD remains to be investigated. To determine the effect of spinal glial cell activation in the coexistence of chronic pain and pruritus in the ACD model, we observed spinal glial cell activation in a mouse model of ACD induced by SADBE.

METHODS

Square acid dibutyl ester (SADBE) was employed to establish ACD model mice and monitor the activation of spinal cord glial cells. Additionally, the Gene Expression Omnibus (GEO) database was utilized to analyze potential mechanisms.

RESULTS

In the ACD model, the behaviors of licking and biting within 35 days after modeling were significantly increased. The expression levels of Iba-1, BDNF, LCN2, GRPR, and GFAP differed significantly from those of the control group. In addition, through GEO data analyses, a strong correlation has been found between pain and IFN-γ. Similarly, in vitro experiments revealed that IFN-γ increased the expression of Iba-1, CD16, and BDNF in BV2 cells and the release of LCN2 in primary astrocytes, thus activating spinal cord glial cells. IFN-γ also induced the phosphorylation of JAK1/STAT1 and the expression of IFNGR1 in BV2 cells and primary astrocytes.

CONCLUSIONS

Collectively, the above findings suggest that the coexistence of chronic pain and pruritus in the ACD model is associated with the activation of spinal microglia and astrocytes. The underlying mechanism involves the binding of IFN-γ to its receptor IFNGR1, which is accompanied by the upregulation of JAK1/STAT1 signaling pathway phosphorylation.