[Effect of advanced glycosylation end products on cell cycle of epidermal keratinocyte and the role of signal pathway].

Objective: To investigate the effect of advanced glycosylation end products (AGE) on cell cycle of epidermal keratinocyte and its possible signal pathway.
Methods: 150 mg/L AGE-human serum albumin (AGE-HSA) was prepared in vitro. Primary cultured keratinocytes in logarithmic growth phase were harvested and divided randomly into: A group [with treatment of defined keratinocyte-SFM (DK-SFM) serum-free medium], B group (with treatment of DK-SFM medium including 150 mg/L AGE-HSA), C group (with DK-SFM medium after treatment of U0126) and group D (with D K-SFM medium including 150 mg/L AGE-HSA after treatment of U0126). Cell cycle distributions were analyzed by flow cytometer. The protein levels of cyclin D1, cyclin B1, CDK4 and p44/42 MAPK were measured by Western blot.
Results: Compared with those of A group, the percentage of S-phase and G2/M-phase keratinocytes were decreased obviously in B group, the percentages of G2/M -phase keratinocytes showed the same tendency in C and D groups [(9.7 +/- 1.1)% , (9.8 +/- 0.7)%, respectively, P <0.05]. Compared with that of A group, the expression of cyclin D1 were decreased significantly in other groups, among which a weak expression was showed in D group. There was no obvious difference between A and B groups in CDK4, or cyclin B1 and p44/42 MAPK protein levels ,which were significantly higher than those in C and D groups.
Conclusion: AGEs inhibit the progress of cell cycle of keratinocytes by downregulation of cyclin D1 expression.