Antroquinonol Exerts Immunosuppressive Effect on CD8⁺ T Cell Proliferation and Activation to Resist Depigmentation...

Antroquinonol was investigated as antioxidant and inhibition of inflammatory responses. Our study was to evaluate its immunosuppressive effect on CD8⁺ T cells and protective effect on depigmentation. CD8⁺ T cells were treated with antroquinonol in vitro, and C57BL/6 mice were treated with antroquinonol with or without H₂O₂in vivo for 50 consecutive days. We found antroquinonol could inhibit proliferation of CD8⁺ T cells and suppress the production of cytokines IL-2 and IFN-γ and T cell activation markers CD69 and CD137 in vitro. H₂O₂ treatment induced depigmentation and reduced hair follicle length, skin thickness, and tyrosinase expression in vivo. Whereas, antroquinonol obviously ameliorated depigmentation of mice skin and resisted the reduction of hair follicle length, skin thickness, and tyrosinase expression induced by H₂O₂. Antroquinonol decreased CD8⁺ T cell infiltration in mice skin, inhibited the production of IL-2 and IFN-γ, and decreased the expression of CXCL10 and CXCR3. Summarily, our data shows antroquinonol inhibits CD8⁺ T cell proliferation in vitro. It also reduces CD8⁺ T cell infiltration and proinflammatory cytokine secretion and suppresses the thinning of epidermal layer in vivo. Our findings suggest that antroquinonol exerts immunosuppressive effects on CD8⁺ T cell proliferation and activation to resist depigmentation induced by H₂O₂.