Oleuropein attenuates inflammation and regulates immune responses in a 2,4-dinitrochlorobenzene-induced atopic dermatitis mouse model
Wen-Chung Huang,1,2 Chian-Jiun Liou,2,3 Szu-Chuan Shen,4 Sindy Hu,5,6 Jane C-J Chao,7 Chun‑Hsun Huang,5,6 Shu-Ju Wu6,8
1 Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City, Taiwan
2 Division of Allergy, Asthma, and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
3 Department of Nursing, Division of Basic Medical Sciences, Research Center for Chinese Herbal Medicine, and Graduate Institute of Health Industry Technology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
4 Graduate Program of Nutrition Science, National Taiwan Normal University, Taipei, Taiwan
5 Department of Cosmetic Science, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City, Taiwan
6 Department of Dermatology, Aesthetic Medical Center, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
7 School of Nutrition and Health Sciences, College of Nutrition, Taipei Medical University, Taipei, Taiwan
8 Department of Nutrition and Health Sciences, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City, Taiwan
Abstract
Background: Olive (Olea europaea Linn) leaves contain a phenolic compound oleuropein (Ole) has antioxidant, anti-inflammatory, and immunomodulatory activities. However, whether Ole might be an effective treatment for atopic dermatitis (AD) remains unknown.
Objective: This study investigated the functional role of oleuropein in a 2,4-dinitrochlorobenzene-induced AD-like mouse model, with a focus on allergic inflammation.
Methods: We evaluated cytokine gene expression, COX-2 inflammatory protein production, and Th2 related cytokine regulation of mast cells and eosinophils that infiltrated AD-like skin lesions.
Results: A topical application of Ole significantly reduced Th2-related cytokine gene expression (IL-4 and IL-5) and inflammatory COX-2 protein production in AD-like skin lesions. Additionally, Ole suppressed serum IgE levels. Furthermore, Ole effectively reduced ear swelling and epidermal and dermal thickening.
Conclusion: These results suggested that, mechanistically, Ole treatment improved allergic inflammation by blocking the Th2-driven inflammatory axis. In conclusion, our findings indicated that Ole showed promise in treating AD by regulating serum IgE and Th2 cytokine levels. Although the effects of Ole on AD in humans require clinical trials, our results provided insights into how AD treatments might be improved.
Key words: Atopic dermatitis, oleuropein, IgE, mast cells, eosinophils, allergic inflammation