The Preventive Effect of Topical Administration of Human Mesenchymal Stem Cells-Conditioned Medium (MSC-CM) on DNCB-Induced Atopic Dermatitis-Like Model in Mice

 Atopic dermatitis (AD) is a chronic inflammatory skin disease for which there is no adequate treatment. Mesenchymal stem cells have already been used to treat inflammatory diseases.  The present study investigated the effect of the administration of human mesenchymal stem cells-conditioned medium (MSC-CM) on the AD model and its relationship with central pain, the level of oxidative, and inflammatory stress factors in the skin.

 The AD model was established by topical administration of a 2% 4,2-dinitrochlorobenzene (DNCB) solution on the dorsal and ear skin of mice. Mice received topical MSC-CM and betamethasone ointment as a positive control three times a day for 2 weeks. Skin interleukin-4 (IL-4) and malondialdehyde (MDA) levels were measured by the ELISA method in all groups. Changes in nociception were assessed by the tail flick test. Histological changes in the body and ear skins were evaluated after hematoxylin-eosin (H&E) staining, and mast cells number in toluidine blue-stained sections were counted in this study.

 Topical administration of MSC-CM and betamethasone was able to reduce pain, inflammation, and changes of dermis thickness in the dorsal and ear skins, as well as the infiltration of mast cells in the skin of groups treated with DNCB. Moreover, MSC-CM, similar to betamethasone, decreased the level of IL-4 and MDA levels in the skin of DNCB receiving groups.

 The increase in IL-4 levels and lipid peroxidation play an important role in inducing AD-like lesions in the skin of the mouse in the DNCB model; in addition, the topical application of the MSC-CM is a potential therapeutic agent for AD.