Objective To investigate the inhibitory effects of topically applied polypeptide from Chlamys farreri(PCF) on the
expressions of P53,
epidermal growth factor receptor(EGFR) and
substance P(
sp) in
hairless mice skin following chronic ultraviolet B irradiation. Methods Hairless mice were randomly divided into five groups(eight in each group): control group, UVB- model group, UVB+50 g/L PCF group, 200 g/L PCF group, and 100 g/L vitamin-C group. Distilling water, PCF, and vitamin C were applied on the backs of the mice (1 mL per mouse a day) in different groups, respectively. The mice were exposed to UVB with a radiant intensity of 5.15×10 -2 J·cm -2 for 30 days (total radiant intensity: 15.45 J·cm -2 ) except those of the control group. Immunohistochemical analysis was employed to examine the expressions of P53, EGFR and SP in the dorsal skin of mice. Results Chronic UVB radiation could induce the overexpressions of mutant P53, EGFR and SP in the skin of hairless mice. The difference between the control group and the UVB-model group was significant ( F=54.23-67.35, q=11.2-19.3, P < 0.01). The expressions of P53, EGFR and SP in the other three groups were decreased than those of the UVB-model group, the differences were also significant ( q=8.9-10.5, P <0.05). The expressions in the 200 g/L PCF group were markedly decreased, and the difference between UVB+50 g/L PCF group and 200 g/L PCF group was significant ( q=12.5-14.6, P < 0.05 ). Conclusion PCF could inhibit the overexpressions of P53, EGFR and substance P and might protect the skin from photocarcinogenesis and photoaging.