850 nm light-emitting-diode phototherapy plus low-dose tacrolimus (FK-506) as combination therapy in the treatment of dermatophagoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice

Abstract Background Light emitting diode (LED) phototherapy is an effective alternative for the treatment of inflammatory skin disorders. Tacrolimus (FK-506) is a potent immunomodulating agent, which has been used to treat AD. Combination therapy is often used in the treatment of AD to improve therapeutic efficacy or to reduce the dose of each drug. Objective To investigate the therapeutic efficacy of monotherapy with either 850 nm LED phototherapy or low-dose FK-506, and combination therapy in dermatophagoides farina (Df)-induced AD-like skin lesions in NC/Nga mice. Methods The Df-induced NC/Nga mice with a clinical score of 7 were used for treatment with LED (10 and 25 J/cm2 ) alone, low-dose FK-506 (1 mg/kg) or in combination. The synergistic effects of combined therapy were evaluated by dermatitis scores, skin histology, skin barrier function, and immunological parameters, such as IgE, NO, Th2-mediated cytokines and chemokines. Results Combination therapy with 850 nm (25 J/cm2 ) LED and low-dose FK-506 showed a significant reduction in the severity of skin lesions. Combined therapy decreased in the serum level of IgE, NO, and in the splenic level of Th2-mediated cytokines and chemokines. Combination therapy significantly also reduced the inflammatory cellular infiltrate into the skin lesions. Moreover, combination therapy led to recovery of skin barrier function in the skin lesions. Conclusions The use of combination of LED phototherapy and low-dose immunosuppressant improved Df-induced AD-like skin lesions in an NC/Nga mouse model by dominantly reducing IgE, NO, suppressing Th2-mediated immune responses, and inhibiting inflammatory cells, as well as improving skin barrier function.