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INTRODUCTION The role of bone marrow mesenchymal stem cells derived exosomes (BMSCs-exo) in skin photoaging was explored in human dermal fibroblasts (HDFs). The underlying mechanism was further explored. METHODS HDFs were exposed to UVB irradiation to establish the cell photodamage models. The cell viability, and levels of oxidative stress-related factors were tested. ELISA was done to detect TNF-α, IL-6 and IL-1β concentration. Western blot was applied for protein examination. RESULTS UVB treatment led to the inhibition of cell viability. But after BMSCs-exo addition, the inhibitory effect was returned in a dose manner. UVB exposure contributed to the increase of ROS and LDH, and the downregulation of SOD. In addition, excessive secretion of TNF-α, IL-6 and IL-1β was also detected in cells exposed to UVB. However, BMSCs-exo addition eliminated the effects of UVB on oxidative stress and inflammation in HDFs. BMSCs-exo inhibited MMP-1 and MMP-3 expression, but promoted collagen I expression. UVB radiation activated the MAPK/AP-1 signaling, manifested as the increase of p-p38, c-Jun and c-Fos protein levels, which was reversed by BMSCs-exo. As a p38 agonist, anisomycin (ANS) counteracted the effect of BMSCs-exo on HDFs viability, oxidative stress and inflammation. CONCLUSION BMSCs-exo protected HDFs against UVB-induced inhibition of cell viability and the activation of cell oxidative stress and inflammation, which might be related to the inhibition of the MAPK/AP-1 signaling pathway.