Codium fragile Extract Ameliorates Respiratory Function by Controlling Allergic Inflammation in Ovalbumin-Induced Bronchial Disorders in Mice

Abstract

This study investigated the effect of Codium fragile (WCF) water extract in reducing allergic inflammation in ovalbumin (OVA)-induced mice. Mice were sensitized to OVA + aluminum hydroxide, administered WCF for one week, and exposed to 1% aerosolized OVA. As a result, WCF intake reduced the OVA-induced increase in CD4+ T cells, CD8+ T cells, the T helper type 2 (Th2)/T helper type 1 (Th1) cell ratio, and inflammatory cells such as eosinophils and lymphocytes. Furthermore, WCF reduced Th2 cytokines such as interleukin (IL)-5, IL-13, and IL-33 and inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and IL-1 beta in lung tissues. A histological analysis showed that WCF intake decreases OVA-induced pulmonary inflammation, bronchial wall thickness, and mucus score and increases pulmonary alveolar area. Moreover, WCF inhibited the nuclear factor kappa B (NF-kappa B) pathway, the transforming growth factor beta (TGF-beta)/Smad pathway, and apoptosis-related proteins in lung tissues that OVA excessively activated. The oleamide (9-octadecenamide) content, representing a physiologically active component of WCF, was analyzed and validated using a high-performance liquid chromatography-photodiode array (HPLC-PDA) system. These results demonstrate that WCF may serve as a potential preventive agent for respiratory dysfunction such as allergic asthma by suppressing NF-kappa B and TGF-beta/Smad pathways.