Abstract: LI Zhou-na， JIN Zhe-hu. Department of Dermatology, Affiliated Hospital of Yanbian University, Yanji 133000, Jilin, China Corresponding author: JIN Zhe-hu, Email: jinzh_621@163.com 【Abstract】 Objective To estimate the influence of pepper and alcohol on irritant contact dermatitis induced by cinnamaldehyde in rabbit ears. Methods Thirty-two Japanese large-ear white rabbits were used in this study, and equally divided into 4 groups to receive intragastric infusion of sodium chloride physiological solution twice daily （control group）, sodium chloride physiological solution once and 50% alcohol solution once daily （alcohol group）, 10% pepper solution once and sodium chloride physiological solution once daily （pepper group）, 50% alcohol solution once and 10% pepper solution once daily （mixture group）, for 7 days. The dose of these solutions for intragastric infusion was uniformly 8 ml/kg. After the appearance of symptoms of irritant contact dermatitis （including increase in water intake, dry stool, vasocongestion of auricle of ears）, the back skin of 4 mice in each group was injured and served as the injured skin subgroup, and the back skin of the other 4 mice in each group remained uninjured and served as the intact skin subgroup. Then, skin irritation test was carried out according to the Hygienic Standard for Cosmetics on both sides of the back of these rabbits with 2% cinnamaldehyde （irritant area） and 70% alcohol （control area） respectively. Skin reaction at the irritated sites was observed and scored at 1, 24, 48 and 72 hours after the irritation. Analysis of variance was conducted to assess the differences in reaction intensity between these groups. Results After 7 days of intragastric infusion, the symptom score was 0.25 ± 0.46 in the control group, significantly lower than that in the pepper group （5.38 ± 0.74, P < 0.01）, alcohol group （7.25 ± 0.71, P < 0.01） and mixture group （12.75 ± 0.70, P < 0.01）. In rabbits with intact skin， the intensity of irritant skin reaction was significantly stronger in the mixture group than in the pepper group at 24 and 48 hours （F = 28.44, 30.33, respectively, both P < 0.05）, while in rabbits with injured skin，the irritant skin reaction was more intense in the alcohol group and mixture group than in the pepper group at 24, 48 and 72 hours（F = 197.12, 94.54, 87.63, respectively, all P < 0.01）. Conclusions Pepper and alcohol alone or in combination at the tested concentration can induce irritation symptoms in rabbits, and both of them can enhance the response of skin to irratation by cinnamaldehyde. 【Key words】 Dermatitis, irritant; Capsicum; Ethanol; Cinnamaldehyde; Disease models, animal

Key words: cinnamic aldehyde