Figure 7.

Effects of Pangasius hypophthalmus fish skin hydrolysates (fsCH) on dermal expression of matrix metalloproteinases (MMP) and collagen degradation in ultraviolet-B (UV-B)-irradiated SKH-1 hairless mice. SKH-1 hairless mice were exposed to UV-B radiation three times a week and treated with 2 mg/kg retinoic acid (RA) intraperitoneally and with 15 mg/kg glycine-proline-hydroxyproline tripeptide (GPH) and 206–412 mg/kg fsCH orally for eight weeks. Skin tissue extracts were electrophoresed on 8–12% SDS-PAGE and subjected to Western blot analysis with a primary antibody against MMP-1, MMP-8, and MMP-13 (A). β-Actin antibody was used as an internal control. The bar graphs (mean ± SEM, n = 3) in the right panels represent quantitative results of the blot bands on the left obtained from a densitometer. The skin tissue MMP-8 expression was immunohistochemically identified by FITC-green staining (B). Serum levels of carboxy-terminal telopeptide of type 1 collagen (CTX-1) and amino-terminal telopeptide of type 1 collagen (NTX-1) were measured by using ELISA kits ((C,D), n = 7). Respective values in bar graphs not sharing a small letter are different at p < 0.05.