Protective Effects Of Chinese Herbals On Ultraviolet Irradiated Human Dermal Fibroblasts

Objective To study the influence of ultraviolet rays (UV) on the dermal fibroblasts in-vitro. To screen out the Chinese herbals with protective effects against UV and to confirm their proper concentration.Methods Human dermal fibroblasts were used in the in-vitro study. Fibroblasts were irradiated by a single exposure to UVA1 (340-400nm) or UVB (280-320nm) and at the same time incubated with, or without chinese herbals(Eucommia ulmoides, Gynostemma pentaphyllum, Saussurea involucrate, Radix Astragali and Thamnolia Vermicularis extracts) and then detected twenty-four hours later. Cell proliferation rate was determined by CCK-8 assay. Expressions of procollagenâ… , procollagenâ…¢(protein levels) and MMP-1, MMP-3 (mRNA level) were detected by enzyme linked immunosorbent assay (ELISA) and Real-time polymerase chain reaction (PCR) separately.Results In in-vitro study, cell proliferation curve after UVA1 or UVB irradiation showed dose dependent decrement pattern.20J/cm2 UVA1 or 40mJ/cm2 UVB significantly inhibited the cell proliferation rate (P<0.01) and procollagenâ… , procollagenâ…¢protein levels (P<0.01), while stimulated MMP-1 and MMP-3 mRNA expression (P<0.01). Eucommia ulmoides extracts, between 0.1mg/ml and 1mg/ml, increased cell proliferation which was previously inhibited by UV (P<0.01). Gynostemma pentaphyllum extracts, between 1mg/ml and 10mg/ml, reversed this effect by UVA1 (P<0.01) or UVB (P<0.05) in some degree. Saussurea involucrate extracts only reversed this effect by UVA1 (0.1 mg/ml, P<0.05; 1mg/ml, P<0.01). Radix Astragali and Thamnolia Vermicularis extracts have no significant effects (P>0.05). Eucommia ulmoides extracts, at the concentration of 1 mg/ml both significantly decreased MMP-1, MMP-3 mRNA expression induced by UVA1 or UVB (P<0.01) and significantly improved the inhibitory effects of UV on procollagenâ… (P<0.01), procollagenâ…¢protein levels (P<0.05).Conclusions UV irradiation damaged the dermal fibroblasts and inhibited their proliferation. It also inhibited the expression of procollagen, stimulated the expression of MMP-1 and MMP-3 which were responsible for the breakdown of various components in the ECM (extracellular matrix). The dose of UVA1 needed to achieve the same damaging effects on dermal fibroblasts in vitro was approximately 500 times equal to that of UVB. Eucommia ulmoides extracts had photoprotective properties against UV irradiation in vitro. Eucommia ulmoides extracts inhibited extracellular matrix degradation and preserved collagen production in dermis and might protect skin from photoaging. Gynostemma pentaphyllum, Saussurea involucrate extracts improved the inhibitory effects on cell proliferation by UVA1 or UVB in some extent.