Protective Effect of Topically Applied Polypeptide from Chlamys farreri Against Ultraviolet Radiation-Induced Chronic Skin Damage in Guinea Pig

Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The chronic ultraviolet irradiated guinea pig model was established, and visible changes in the skin including wrinkling, sagging and erythema were observed. Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH px) in the dorsal skin were determined using biochemical methods. The results showed:(1)PCF (5 % and 20%) could greatly protect the dorsal skin of guinea pig against wrinkling, sagging and erythema induced by UV radiation in a concentration dependent manner.(2)PCF could reduce MDA formation in the dorsal skin caused by UV irradiation, while increasing the activities of SOD and GSH px.(3)The differences among the PCF groups and UV model group were significant ( P <0.05, P <0.01). These results indicated that topical application of PCF provided broad solar UV spectrum photoprotection; and that the antioxidant property of PCF might play a role in photoprotection.

The Polypeptide in Chlamys farreri can protect human dermal fibroblasts from ultraviolet B damage

To investigate the effect of polypeptide from Chlamys farreri (PCF) on NHDF in vitro, we modeled oxidative damage on normal human dermal fibroblasts (NHDF) exposed to ultraviolet B (UVB). In this study, 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydro-genase (LDH) were tested to measure cell viability. Enzymes including superoxide dismutase (SOD), glu-tathione peroxidase (GSH-PX), catalase (CAT) and xanthine oxidase (XOD) were determined biochemically. Total antioxidative capacity (T-AOC) and anti-superoxide anion capacity (A-SAC) were also determined. Ultrastructure of fibroblasts was observed under transmission electron microscope. The results showed that: UVB (1.176×10-4 J/cm2) suppressed the growth of fibroblasts and the introduction of PCF (0.25%-l%) before UVB reduced the suppression in a concentration-dependent manner. PCF could enhance the activities of SOD, GSH-PX and T-AOC as well as A-SAC. Also PCF could inhibit XOD activity, while it did not affect CAT activity. Ultrastructure of fibroblasts were damaged after UVB irradiation, concentration-dependent PCF reduced the destructive effect of UVB on cells. These results indicated that PCF can protect human dermal fibroblasts from being harmed by UVB irradiation via its antioxidant pro-erty.

Effects of polypeptide from Chlamys farreri on amino acid con-tent in guinea pig skin irradiated by chronic ultraviolet A and B

We examined the effects of polypeptide from Chlamys farreri (PCF) on the amount of hy-droxyproline in guinea pig skin irradiated by chronic ultraviolet A (UVA) and ultraviolet B (UVB) radiation. PCF was applied locally before repeated exposure of guinea pig to UVA and UVB. The contents of hy-droxyproline and other amino acids in guinea pig skin were determined by automatic amino acid analyzer. Our results showed that: (1) long-time UVA and UVB radiation can reduce dramatically the amounts of hy-droxyproline, aspartic acid, threonine, glycine, phenylalanine and lysine in guinea pig skin in comparison with the control group (P < 0.05); (2) Compared with model group, pre-treatment with 5 % and 20 % PCF prior to UVA and UVB radiation can inhibit the decline of amino acids content in guinea pig skin in a dose-dependent manner (P < 0.05). As the decrease of hydroxyproline, glycine and lysine contents in the skin directly reflexes type I collagen degeneration, our results indicated that the chronic application of PCF can protect skin type I collagen against UV radiation, and thus protect skin from photoaging.