Abstract: Objective: To determine the expression of collagen metabolism and the related signaling pathway in skin aging rat models induced by D-Galactose. Methods: Twenty rats were randomly divided into the D-gal group and control group. Ten rats in the D-gal group were given subcutaneous injection of D-galactose，125mg/kg?d for 6 weeks. The rats in the control group were treated with the same volume of normal saline. The collagen density was detected by the confocal microscopy. The expression of ColⅠ, ColⅢ, MMP-1, TIMP-1, TGFβ1 and Smad3 mRNA was detected by RT-PCR. Results: The collagen density of rats and the level of ColⅠ, MMP-1, TIMP-1, TGFβ1 and Smad3 mRNA were lower in the D-gal group than in the control group (P<0.05). The expression of MMP-1mRNA was higher in the D-gal group than in the control group. There was no significant difference in the level of ColⅢ between the D-gal group and control group. Conclusion: D-Galactose inhibits the ColⅠ synthesis through down-regulating the expression of TGFβ1/Smad3 and accelerates the degradation of collagen through regulating the balance between MMP-1 and TIMP-1, which makes the skin into subacute aging.

Key words: D-Galactose, rat skin aging model, collagen metabolism, TGFβ1/smads pathway