Objective:This study is to analyze the differential proteins expressed in the normal elderly exposed epidermis and the non-exposed epidermis.Methods:The proteins were extracted from the exposed and non-exposed elderly separated epidermis

and were submitted to two-dimensional gel electrophoresis.Then their electrophoretic patterns were analyzed by the PDQUEST software and identified by MALDI-TOF MS.The following steps were database query and probation using Western-blotting.Results:By comparison the two groups of two-dimensional electrophoresis patterns

15 differential protein spots were determined

in which 5 differential protein spots were successfully identified by MALDI-TOF analysis and database queries

and 4 proteins

Heat shock protein B1(HSPB1)

Annexin A2(ANXA2)

Keratin

typeⅡ cytoskeletal 80(K2C80)

Mitogen-activated protein kinase 3(MK03)

were highly expressed in exposed group while Glutathione S-transferase A2(GSTA2) was highly expressed in non-exposed group.Conclusion:The changes in expression of 5 identified proteins may have a close relationship with photoaging

that helps revealing molecular mechanism of epidermal cells in photoaging.