Protective Effect Of Ferulic Acid On Human Fibroblasts Against Ultraviolet-A Induced Photoaging

Objective:Aging is a complex, progressive process that leads to functional and esthetic changes in the skin. This process can result from both intrinsic as well as extrinsic processes. Photoaging is a term used for the characteristic changes to skin induced by chronic UVA and UVB exposure. UVA irradiation(320~400nm) of sunlight is the most effective wavelength in causing photoaging. The fibroblast of dermis is the main target site. The clinical signs associated with photoaging are dyspigmentation, laxity, wrinkles, telangiectasia, a leathery appearance, and cutaneous malignancies. As environmental pollution has become increasingly serious, individuals are seeking treatment for reversal of UV-induced changes in skin.Recent evidence indicated that transforming growth factor-β(TGF-β1) could activate the fibroblast proliferation and extracellular matrix(ECM)generation. Up regulation of matrix metalloproteinases(MMPs), particularly collagenase-1(MMP-1), is responsible for the lysis of dermal collagen and elastin fibers during chronological skin aging. p66 Shc modulates the production of cellular ROS and cellular aging signaling pathway. These factors plays an important role in the occurrence and the development of the photoaging.Ferulic acid is a hydroxycinnamic acid, a type of organic compound. It is an abundant phenolic phytochemical found in plant cell wall components. Ferulic acid, like many natural phenols, is an antioxidant in vitro in the sense that it is reactive toward free radicals such as reactive oxygen species(ROS). Ferulic acid may have pro-apoptotic effects in cancer cells, thereby leading to their destruction. Earlier studies have shown that Ferulic acid has photo-protective efficiency and inhibits the proliferation decreasing induced by UVA by strengthening antioxidation and decreasing oxygen radicals.Ferulic acid can also relieve the oxidation damaged from UVB irradiation to HaCaT cells by strengthening antioxidation and decreasing oxygen radicals.However, whether Ferulic acid could protect skin fibroblasts from UVA induced photoaging? The aim of this study was to investigate the protective effects of Ferulic acid on UVA induced photoaging on human fibroblasts and its possible mechanisms. MethodsSubconfIuent fibroblasts were cultured and divided into norma1 control group,ferulic acid group,UVA irradiation group and UVA plus ferulic acid group. Subconfluent fibroblasts were shammed or irradiated with 10J/ cm2 of UVA irradiation and treated with 200μg/mL Ferulic acid.1.The ageing condition was determined by histochemical staining of senescence associated β-galactosidase(SA-β-Gal).2. Enzyme-linked immunosorbent assay(ELISA) was applied to detect the levels of TGF-β1 in the supernatant.3.The mRNA levels of MMP-1、TIMP-1and p66 Shc were measured by real-time quantitative PCR. Results:1.UVA irradiation raised the proportion of SA-β-Gal positive cells in comparison with untreated cells. Ferulic acid could decrease the number of SA-β-Gal positive cells.2.Ferulic acid treatment could promote the secretion of TGF-β1. With UVA irradiation, the content of TGF-β1 in the supernatant were decreased, and Ferulic acid treatment recovered the content of TGF-β1.3.UVA irradiation also up-regulated the mRNA levels of MMP-1, TIMP-1and p66 Shc. Incubation with Ferulic acid treatment inhibited these changes.The intervention of Ferulic acid could decrease the levels of SA-β-Gal, and the mRNA levels of MMP-1 and p66 Shc compared with UVA group(P<0.05), while the TIMP-1 expression was increased. Conclusion:These results showed that Ferulic acid could delay the photoaging from UVA irradiation. Its mechanism may be related with antioxidation and decreasing the collagen degradation.