Fig. 1

Acceleration of skin wound healing by the systemic and topical administration of SPD. a, b Two independent excisional biopsies (5 mm in diameter) were taken from the right and left dorsal side of each mouse (n = 6). Distilled water containing spermidine (5 mM) was administered daily from 4 days before skin wound creation. Biopsy sites were treated with white petrolatum containing PBS or SPD (2 μg/wound) 0 and 2 days after skin wound creation. Each wound was recorded via digital photography, and the scale bar represents 10 mm. The mean rate of repair was calculated based on the original wound area of each biopsy site. *p < 0.05, white petrolatum with SPD group compared to white petrolatum with PBS group. ^†p < 0.05, SPD-containing water + white petrolatum with PBS group compared to white petrolatum with PBS group. c PCNA protein levels after wound creation were examined by western blot analysis and normalized using GAPDH protein levels. Each data point and error bar represent the mean and SE, respectively, of data from triplicate or quadruplicate samples. *Indicates a statistically significant differences; p < 0.05. ***Indicates a statistically significant difference; p < 0.005