Research Paper Volume 14, Issue 20 pp 8167—8178

Figure 4. Effects of SFRP4 knockdown on the skin of aging mice. (A) Time course of the experiment. (B) RT-PCR analysis of SFRP4 and SASP gene expression in total skin extract. (C) Western blot analysis of collagen III and SFRP4 expression in whole skin extracts. SFRP4 siRNA treatment suppressed the expression of SASP factors and aging-related proteins, and increased collagen III. (D) H-E staining of skin from young (15 weeks old), control (PBS) aged, negative siRNA, and SFRP4 siRNA mice; thinning of subcutaneous adipose tissue and panniculus carnosus was observed in the control aged and negative siRNA groups. SFRP4 siRNA treatment improved these phenotypes. SF: Subcutaneous fat tissue; PC: Panniculus carnosus. Bar = 100 μm. (E) Skin in each intervention mouse; Masson’s trichrome staining; reduced thickness and density of collagen fibers and dermal connective tissue were observed in control aged mice and negative siRNA-treated mice, but the same improved with SFRP4 siRNA treatment. Collagen fibers are shown at higher magnification in the lower panel. Bar = 100 μm in the overall view, bar: 5 μm in magnified view. *; P < 0.05. Experiments were performed with n = 5 for each group. One-way ANOVA and Tukey’s post hoc test were used to compare differences between three groups.