In vivo and in vitro anti-allergic and anti-inflammatory effects of Dryopteris crassirhizoma through the modulation of the NF-ĸB signaling pathway in an ovalbumin-induced allergic asthma mouse model

Dryopteris crassirhizoma (DC) has a wide range of pharmacological effects, including antibacterial, anti-influenza virus, anti-tumor, anti-reverse transcriptase and antioxidant effects. However, the inhibitory effect of DC on allergic inflammatory response remains unclear; therefore, the current study used an experimental ovalbumin (OVA)-induced allergic asthma mouse model and phorbol myristate acetate (PMA)- and A23187-stimulated HMC-1 cells to reveal the effects of DC in regulating airway inflammation and its possible mechanism. Allergic asthma was initiated in BALB/c mice via exposure to OVA emulsified in aluminum, on days 1 and 14. Thereafter, the mice were treated with DC or dexamethasone (Dex) orally, before being challenged, from days 15 to 26. Subsequently, the mice were challenged with OVA on days 27, 28 and 29. The results of histological analysis indicated that the administration of DC decreased the number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and suppressed eosinophilic infiltration, mucus production and collagen deposition in the lung tissue. DC treatment increased the level of T helper type 1 (Th1) cytokines (IL-10 and interferon (IFN)-γ) and decreased the levels Th2 cytokines (IL-4, IL-5 and IL-13) and proinflammatory cytokines (IL-6 and TNF-α). Furthermore, DC treatment inhibited the activation of NF-κB signaling (NF-κB, p-NF-κB, IκB and p-IκB), both in BALF and lung homogenates. Serum levels of total IgE and OVA-specific IgE and IgG1 were significantly lower after DC treatment compared with after OVA treatment. However, the anti-inflammatory effect of OVA-specific IgG2a was higher after DC treatment. In addition, DC treatment attenuated the production of proinflammatory cytokines, including IL-6 and TNF-α, and the activation of NF-κB signaling (NF-κB and p-NF-κB), in PMA and calcium ionophore A23187-stimulated HMC-1 cells. In summary, the current study demonstrated that DC acts a potent anti-allergic and anti-inflammatory drug by modulating the Th1 and Th2 response and reducing the allergic inflammatory reaction in PMA and A23187-stimulated HMC-1 cells via NF-κB signaling in an OVA-induced allergic asthma model.