Therapeutic effects of topically-administered guar gum nanoparticles in oxazolone-induced atopic dermatitis in mice

Abstract

Introduction: Atopic dermatitis (AD) is a chronic disease of the skin, involving itchy, reddish and scaly lesions. It mainly affects children and has a high prevalence in developing countries. AD may occur due to environmental or genetic factors. Currently, all therapeutic strategies involve methods to simply alleviate the symptoms, and include lotions and corticosteroids, which have adverse effects. Use of phytochemicals and natural products has not yet been exploited fully. The particle used in this study is derived from Cyamopsis tetragonoloba, an edible polysaccharide with a galactomannan component. The mannose component mainly increases its specificity towards cellular uptake by mannose receptors, highly expressed by macrophages. The aim of this study was to determine the therapeutic effect of guar gum nanoparticles (GN) in vitro and in vivo in AD. Methods: To assess the wound healing capacity of GN, we first treated adherent fibroblast cells, with a scratch injury, with GN. GN successfully healed the wound caused by the scratch. In the in vivo experiments, Balb/c mice ears were treated topically with oxazolone (Oxa) to induce AD, and then were topically treated with GN. The ear thickness increased significantly until day 28 upon treatment with Oxa. Results: Application of GN showed a significant decrease in ear thickness as assessed on day 28. The total cell count of skin cells that showed a fold increase, when treated with Oxa, was again decreased after topical application of GN on the affected skin. The eosinophil count, as assessed by Giemsa staining, was also increased when treated with Oxa, while GN application led to a significant decrease. Serum IgE levels were restored by GN. T helper cell and macrophage populations, when examined by flow cytometry, showed an increase in percentage when treated with Oxa; the percentage was reduced after application of GN. Hematoxylin & Eosin (H&E) staining of the ear tissue showed an increase in epidermal thickness in Oxa-treated mice, while GN application showed reduced cellular infiltration and epidermal thickness. Conclusion: Overall, our results showed that GN, when administered topically, was successful in alleviating dermatitis caused by Oxa.