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. 2020 Dec 1;10:20940. doi: 10.1038/s41598-020-77039-5

Figure 1.

Figure 1

Figure 1

Eucalyptus oil (Eu) suppresses passive cutaneous anaphylaxis (PCA) in a mouse model. (a) Schedule of treatment and experimental procedures for the PCA and ear swelling response tests. (b) Anti-DNP-IgE was injected intravenously 24 h before DNFB application. One hour before DNFB application, Eucalyptus oil or vehicle (3:1 acetone/olive oil) was applied to the inside of each ear of all animals. DNFB was applied to the outside of the ear, followed by an immediate injection of Evans blue dye. Thirty minutes later, the ears were excised, and the absorbance of the dye was measured. Data are presented as the mean ± SEM (N = 8/group). The statistical significance of the differences was assessed using Dunnett’s test (**P < 0.01 versus vehicle-DNFB). (c) The time course of ear oedema was investigated. Ear thickness was measured using a thickness gauge. Data are presented as the mean ± SEM (N = 8/group). (d) Haematoxylin and eosin staining of ear tissue 6 h after DNFB application. (e,f) Toluidine blue staining of ear tissue 1 or 6 h after DNFB application. (e) Tissue sections were mast cells obtained from ear tissue collected 6 h after the application of DNFB. Mast cells were identified in tissue sections by their characteristic granular, deep blue-purple metachromatic appearance against blue orthochromatic background tissue. ND no degranulation, D degranulation. (f) Left panel shows the number of cutaneous mast cells at the dermal/epidermal (D/E) junction. Right panel shows the percentage of degranulated mast cells. Each bar is mean ± SEM (N = 6/group) of 12 fields of views. Statistical significance of the differences was assessed using the Tukey–Kramer test (**P < 0.01 versus vehicle, ##P < 0.01 versus vehicle-DNFB).