Abstract: Objective To investigate the relationship between expression of matrix metalloproteinases of dermal fibroblasts and wrinkle formation in photoaging skin.Methods In situ hybridization histochemistry and immunocytochemistry were used to detect the expression of matrix metalloproteinases MMP-1,MMP-3 mRNA and the expression of tissue inhibitor of MMP-1at(TIMP-1)protein in dermal fibroblasts from non-lesional skin of psoriatic patients during and after PUVA treatment.Results The expression of MMP-1 and MMP-3 mRNA of dermal fibroblasts from non-lesional skin was persistently up-regulated during PUVA therapy,and lasted more than 6 months after treatment;while the expression of TIMP-1protein was only slightly expressed for a short period during PUVA therapy.Conclusion Wrinkle formation in photoaging skin after PUVA therapy is correlated with the imbalance of expression of matrix metalloproteinases and their inhibitors of dermal fibroblasts.

Key words: Skin aging, Metalloproteinases, Fibroblasts