Topical Administration of Manuka Oil Prevents UV-B Irradiation-Induced Cutaneous Photoaging in Mice
Manuka oil inhibits UV-B-induced production of inflammatory cytokines and infiltration of macrophages. The amount of TNF-α (a) and IL-1β (b) were estimated using ELISA in the total protein extract of dorsal skin biopsies obtained at the end of the experiment from the no UV-B irradiation control group (no UV-B), vehicle only group (vehicle), and the group that received 10% manuka oil (manuka oil), respectively. Data represent mean ± SEM ( per group). ##: significantly different from no UV-B control group (). * and **: significantly different from vehicle only group ( and ). (c) Representative images (×200) from immunohistochemical staining of infiltrated macrophages in dorsal skin biopsies obtained at the end of the experiment. An example of stained macrophage was denoted by a red arrow. Scale bar: 200 μm. (d) Average values ± SEM of macrophage numbers counted per field were represented as a bar graph ( per group).