Fig. 1

Schematic diagram of the experimental design. (a) Induction of contact dermatitis in mice and topical PPE treatment of skin lesions. Skin inflammation was induced on the back skin of BALB/c mice by periodic topical application of DNCB-treated patches. One day prior to sensitization, mouse dorsal hairs were completely removed, and 1% DNCB-treated patches were attached to back skin for 20 h on days 0, 3 and 6. Following sensitization, 0.5% DNCB patches were applied on days 9, 12, and 15 for elicitation of responses. Upon removal of DNCB patches, PPE in cream was topically applied to skin lesions every day until the end of the experiment (total of 17 days). PBS or cream (vehicle) alone was applied as a negative control and DEX treatment used as a positive control. (b) Experimental conditions for each mouse group. Mice were divided into 5 groups representing different experimental conditions (n = 6 per group). Except for the normal group, DNCB in AOO was applied to four mouse groups (designated DNCB, DNCB+vehicle, DNCB+DEX, DNCB+PPE) to induce skin inflammation. PPE was mixed with cream and topically applied to skin lesions to determine effects on inflammation