Different molecular weight hyaluronic acid alleviates inflammation response in DNFB-induced mice atopic dermatitis and LPS-induced RAW 264.7 cells

Aims: Atopic dermatitis (AD) is an inflammatory chronic disease which severely interferes the life of patients. Hence, there is a great need for new therapies. Hyaluronic acid (HA) is an effective potential inflammation modifier; however, there is limited information about their implementation in inflammation therapies. This study aimed to evaluate the anti-inflammatory activities of HA and the influence of its molecular weight. Main methods: Male C57BL/6 J mice were stimulated by 2,4-dinitrofluorobenzene to induce AD-like symptoms and immune response. The skin lesions and histopathological change, as well as levels of inflammatory factors were evaluated. RAW 264.7 mouse macrophages were treated with lipopolysaccharides (LPS) to induce inflammation. NO, IL-6, and TNF-alpha levels were detected through ELISA kits. Key findings: DNFB challenge induced mice AD symptoms including epidermal thickening, mast cell infiltration, Th2/Th1 immune response, skin lesions IL-4 and IFN-gamma, and serum IgE elevation. HA treatment ameliorated such symptoms through the inhibition of PI3K/Akt signaling pathway. LPS induction stimulated the secretion of NO, IL-6, and TNF-alpha in RAW 264.7 cells, while HA pre-treatment reduced the concentration of the cytokines in cell supernatants. Significance: These findings give clear insight into the interaction between HA and inflammatory response, which can help guiding the utilization of HA in the AD therapies.