Fig. 3

Hesperetin ameliorates UVB-induced skin photoaging in a Cisd2-dependent manner. A The protocol for treatment with hesperetin and its effect on UVB-induced skin damage in WT and Cisd2 KO mice at 3-month old. The mice were pre-treated with hesperetin (10 mg/kg/day, i.p. injection) for 7 days, and then exposed to UVB (312 nm, 349 mJ/cm²/75 s) light once a day for 5 days in a UVB box. Mice were sacrificed at 6 days after the first UVB exposure. B Western blot analysis of the level of Cisd2 protein in the skin of Veh-treated or Hes-treated mice after UVB exposure. C Masson’s trichrome staining of skin sections from the various different groups of mice. UVB exposure significantly induced skin damage and increases skin thickness, which is one of the major characteristics of photoaging. D Quantification of the total, epidermal and dermal layers of skin thickness in various different groups of mice. Hesperetin treatment ameliorates UVB-induced skin photoaging in the WT mice. However, hesperetin has no obvious beneficial efficacy when Cisd2 is absent in the Cisd2 KO mice. E Total reactive oxygen and nitrogen species (ROS & RNS) levels in the skin tissues of Veh-treated or Hes-treated WT mice after UVB exposure. F Western blot analysis of MMP-1 protein (a marker of UV damage) in the skin of Veh-treated or Hes-treated WT mice after UVB exposure. Data are presented as mean ± SD. *p < 0.05; **p < 0.005 by one-way ANOVA with Bonferroni multiple comparison test. UT untreated