Anti‑photoaging effect of fermented agricultural by‑products on ultraviolet B‑irradiated hairless mouse skin

Abstract

Processed products from agricultural produce generate a large number of agricultural by‑products that contain a number of functional substances. These are often discarded owing to the lack of suitable processing methods. The present study investigated the anti‑photoaging properties of fermented rice bran (FRB), soybean cake (FSB) and sesame seed cake (FSC) on ultraviolet B (UVB)‑irradiated hairless mouse skin. Results indicated that the oral administration of FRB, FSB and FSC effectively inhibited the UVB irradiation‑induced expression of matrix metalloproteinase (MMP)‑2, MMP‑9, MMP‑3 and MMP‑13. Reverse transcription‑quantitative polymerase chain reaction results also demonstrated that FRB, FSB and FSC significantly inhibited the UVB‑induced expression of the genes encoding tumor necrosis factor‑α, inducible nitric oxide synthase, interleukin (IL)‑6 and IL‑1β when compared with the UVB‑vehicle group (P<0.05). Additionally, collagen degradation and mast cell infiltration were reduced in hairless mouse skin. Furthermore, UVB‑induced wrinkle formation was also significantly reduced in mouse skin compared with the UVB‑vehicle group (P<0.05). These results reveal that fermented agricultural by‑products may serve as potential functional materials with anti‑photoaging activities.

Figure 1

Effect of FRB, FSB and FSC on the body weights of hairless mice. (A) Body weights and (B) food efficiency rates of the mice from the six groups. The body weight of each mouse was measured once a week and the food efficiency rate was calculated using the equation: Total weight gain/total food intake ×100. All values are presented as the mean ± standard deviation. The Kruskal-Wallis nonparametric test and Bonferroni's post-hoc test were used to control for multiple comparisons. FRB, fermented rice bran; FSB, fermented soybean cake; FSC, fermented sesame seed cake; UVB, ultraviolet B; RA, retinoic acid.

Figure 2

Effects of FRB, FSB and FSC on UVB-induced wrinkle formation in hairless mice. (A) Features of the dorsal skin and (B) mean skin wrinkle depth of hairless mice exposed to UVB for 8 weeks. Wrinkle formation was measured via replica grading in the final week and investigated using a scoring system. All values are presented as the mean ± standard deviation. One-way analysis of variance and Scheffe's post-hoc test were used to control for multiple comparisons. ^cP<0.001 vs. normal control mice. FRB, fermented rice bran; FSB, fermented soybean cake; FSC, fermented sesame seed cake; UVB, ultraviolet B; RA, retinoic acid.

Figure 3

Moisturizing effect of FRB, FSB and FSC on UVB-induced hairless mice. (A) TEWL in dorsal skin and (B) β-glucosidase activity. To estimate the TEWL, the dorsal skin of each mouse was examined using an appropriate probe. β-glucosidase activity was measured via an enzyme assay that monitored the conversion of 4-methylumbellifery-β-D-glucopyranoside to 4-methylumbelliferone. All values are presented as the mean ± standard deviation. One-way analysis of variance and Scheffe's post-hoc test were used to control for multiple comparisons. ^aP<0.05, ^bP<0.01 and ^cP<0.001 vs. normal control mice. TEWL, transepidermal water loss; FRB, fermented rice bran; FSB, fermented soybean cake; FSC, fermented sesame seed cake; UVB, ultraviolet B; RA, retinoic acid.

Figure 4

Inhibition of UVB-induced histological alteration by FRB, FSB and FSC in hairless mice. Histological alterations of epidermal thickness, collagen degradation and mast cell infiltration were analyzed using (A) haemotoxylin and eosin staining, (B) epidermal thickness of dorsal skin, (C) Masson's trichrome staining and (D) toluidine blue staining, respectively. All values are presented as the mean ± standard deviation. A Kruskal-Wallis nonparametric test and Bonferroni's post-hoc tests were used to control for multiple comparisons. ^bP<0.01 vs. normal control mice. FRB, fermented rice bran; FSB, fermented soybean cake; FSC, fermented sesame seed cake; UVB, ultraviolet B; RA, retinoic acid.

Figure 5

Effects of FRB, FSB and FSC on MMP and cytokine expression in UVB-induced hairless mice. (A) MMP-2, MMP-9, MMP-3 and MMP-13 expression levels determined using RT-qPCR. Total cellular RNA was extracted using RNAzol from skin tissues. Next, 3 µg total RNA was used for cDNA synthesis via RT-qPCR with the appropriate primer sequences. (B) Enzyme-linked immunosorbent assay kit-mediated determination of the MMP-2 protein expression. (C) Measurement of inflammation-associated cytokines using RT-qPCR. All values are presented as the mean ± standard deviation. A Kruskal-Wallis nonparametric test and Bonferroni's post-hoc tests were used for MMP-3, MMP-13, TNF-α and IL-1β groups and one-way analysis of variance and Scheffe's post-hoc test were used to control for multiple comparisons. ^aP<0.05, ^bP<0.01 and ^cP<0.001 vs. normal control mice. RQ, MMP, matrix metalloproteinase; TNF-α, tumor necrosis factor-α; COX-2, cyclooxygenase-2; iNOS, inducible nitric oxide synthase; IL, interleukin; FRB, fermented rice bran; FSB, fermented soybean cake; FSC, fermented sesame seed cake; UVB, ultraviolet B; RA, retinoic acid; RT-qPCR, reverse transcription-quantitative polymerase chain reaction.