OBJECTIVE To study the synergistic protective effects of wheat germ(Triticum aestivum) peptides and swertimarin in mice with ultraviolet B(UVB)-induced solar dermatitis.

METHODS KM mice were randomly divided into 6 groups(n=12): blank group, model group, rehabilitated new group(KFXY), 40 mg·kg⁻¹ wheat germ peptide group(DSM1), 40 mg·kg⁻¹ swertiamarin group(DSM2), and 20 mg·kg⁻¹ wheat germ peptide+20 mg·kg⁻¹ swertiamarin group(DSM3). Mice in the blank group were only shaved and not irradiated, while the remaining groups were irradiated with UVB. The drug delivery groups received topical application for 7 d. At the end of the experiment, photos were taken to record the skin status of the mice, and the skin tissues were stained with hematoxylin-eosin staining(HE), picric acid-acidic magenta method(VG). The content and viability levels of oxidative stress indicators T-AOC, NOS, NO and MDA in skin tissues were detected by biochemistry, the levels of inflammatory indicators TNF-α, IL-6 and IL-1β in skin tissues were detected by immunohistochemistry, the mRNA levels of NQO1, GCLC and Nrf2 in skin tissues were detected by qRT-PCR. The protein levels of NQO1, GCLC and Nrf2 in skin tissues were detected by Western blotting.

RESULTS Compared with the model group, the degree of skin damage in the DSM1, DSM2 and DSM3 groups was improved, the collagen fibers were neatly arranged, the collagen density were increased, the levels of T-AOC were increased, the levels of NOS, NO and MDA were decreased, the expression levels of TNF-α, IL-6 and IL-1β were decreased, the mRNA and protein expression levels of NQO1, GCLC and Nrf2 were increased.

CONCLUSION Wheat germ peptide and swertiamarin in combination ameliorated UVB-mediated solar dermatitis in mice, which may be related to activation of the Nrf2 pathways.