Polypeptide from Chlamys farreri attenuates murine thymocytes damage induced by ultraviolet B.

AIM: Polypeptide from Chlamys farreri (PCF, molecular mass is 879) is a new marine polypeptide compound isolated from Chlamys farreri. This study investigates the possible protective roles and the mechanism of PCF against ultraviolet B (UVB)-induced apoptosis in murine thymocytes. METHODS: The rate of apoptosis and caspase-3 activation was measured by flow cytometry. The expression of stress-response genes c-fos and c-jun was observed by RT-PCR. Western blot analysis was performed to determine the release of cytochrome c. RESULTS: It was found that UVB induced murine thymocyte death. The cells treated with UVB showed an increase in cytochrome c release, caspase-3 activity, as well as in the expression of c-fos and c-jun. In addition, all were involved in UVB-induced cell apoptosis. CONCLUSION: Our present observations pointed to the ability of PCF to avert UVB-induced apoptosis in thymocytes by modulating c-fos and c-jun expression, cytochrome c release, and the consequent activation of caspase-3, which were essential components of the UV-induced cell apoptotic pathway. The results suggested that PCF is a promising protective substance against UV radiation.

Inhibitory effect of polypeptide from Chlamys farreri on ultraviolet A-induced oxidative damage on human skin fibroblasts in vitro.

We have previously reported that polypeptide from Chlamys farreri (PCF) inhibits the oxidative damage of ultraviolet A (UVA) on HeLa cells in vitro [Acta Pharm. Sin. 23 (2002) 961]. To further elucidate a possible role for PCF on UVA-damaged normal human cells, we established the oxidative damage models of normal human dermal fibroblasts (NHDF) exposed to UVA to study the protective effect of PCF on human dermal fibroblasts in vitro. In this study, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the cell viability. The intracellular superoxide dismutase (SOD), glutathione peroxidase (GSH-px), catalase (CAT), xanthine oxidase (XOD), malondialdehyde (MDA), reactive oxygen species (ROS), total antioxidative capacity (T-AOC), and anti-superoxide anion capacity (A-ASC) were measured. The effect of PCF on UVA-induced apoptosis were investigated by Annexin V-FITC assay. Intracellular calcium was determined with the calcium-sensitive fluorochrome Fluo-3, and mitochondrial transmembrane potential with rhodamine 123. Comet assay was employed to detect the UVA-induced DNA damage. The ultrastructure of cell was observed under transmission electron microscope. The results indicated that PCF could greatly enhance the viability of NHDF and markedly promote SOD, GSH-px, T-AOC, and A-ASC, while the amounts of MDA and ROS, the activity of XOD were decreased. PCF could inhibit UVA-induced apoptosis and DNA damage in NHDF. The concentration of cellular free calcium was decreased and the mitochondrial transmembrane potential was increased by PCF. In ultrastructure of NHDF, PCF could greatly decrease UVA-induced damage, especially membrane. Our results suggest that the supplementation of PCF appears to reduce the UVA-induced normal human dermal fibroblasts damage efficiently. It may be involved in the PCF's abilities of scavenging oxygen free radical, inhibiting lipid peroxidation, increasing antioxidative enzymes, decreasing intracellular calcium and protection of membrane structure in NHDF irradiated by UVA.

Protective effect of polypeptide from Chlamys farreri on mitochondria in human dermal fibroblasts irradiated by ultraviolet B.

AIM: To study the effect of polypeptide from Chlamys farreri (PCF) on mitochondria of human dermal fibroblasts irradiated by ultraviolet B (UVB) in vitro. METHODS: Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were determined by biochemical methods. Mitochondrial transmembrane potential was measured by flow cytometry. Ultrastructure of fibroblasts was observed with transmission electron microscope. RESULTS: UVB (1.176 x 10(-4) J/cm(2)) induced mitochondria damage in dermal fibroblast and PCF (0.25%-1%) reduced the damage in a concentration-dependent manner. Furthermore, PCF also concentration-dependently maintained the stability of mitochondrial transmembrane potential. PCF was able to reduce the MDA formation caused by UVB, meanwhile increased the activities of SOD and GSH-PX. The differences among the PCF groups and UVB model group were significant (P<0.05, P<0.01). CONCLUSION: The UVB-induced mitochondria damage was alleviated by PCF in human dermal fibroblasts.