Effects of astragaloside on the transforming growth factor (TGF)-β pathway in photoaged skin of mice

Objective To study the protective mechanism of astragaloside on skin photoaging. Methods BALB/c mice were randomly divided into four groups: model group irradiated with ultraviolet rays (UV), model plus matrix group pretreated with the matrix before UV irradiation, model plus astragaloside group pretreated with astragaloside 0.08% cream before UV irradiation, normal control group received no irradiation or pretreatment. After 4-week irradiation, the mice were sacrificed, and skin tissues were resected from the back of these mice. Then, reverse transeription PCR (RT-PCR) and immunohistochemistry were performed to detect the mRNA and protein expression of TGF-βR Ⅱ and Smad 7, respectively. Gray scale ratio was used to represent the mRNA levels of TGF-βR Ⅱ and Smad 7. Results There was a significant difference in the mRNA level (F = 80.98, 736.80, respectively, both P 0.01). Conclusion Astragaloside can prevent skin photoaging by the alteration of TGF-β pathway via up-regulating TGF-βR Ⅱ expression and down-regulating Smad 7 expression. Key words: Astragaloside;  Skin aging;  Models, animal;  Transforming growth factor beta;  Smad 7 protein