Asthma is characterized by airway
inflammation and
airway remodeling. Our previous study revealed that grape seed
proanthocyanidin extract (GSPE) could inhibit asthmatic airway
inflammation and
airway hyper-responsiveness by down-regulation of
inducible nitric oxide synthase in a murine model of acute
asthma. The present study aimed to evaluate GSPE's effects on airway
inflammation and
airway remodeling in a chronic asthmatic model. BALB/c mice were sensitized with
ovalbumin (OVA) and then were challenged three times a week for 8 weeks. Airway responsiveness was measured at 24 h after the last OVA challenge. HE staining, PAS staining, and Masson staining were used to observe any airway
inflammation in the lung tissue, airway mucus secretion, and subepithelial
fibrosis, respectively. The
cytokines levels in the lavage fluid (BALF) in addition to the total serum
immunoglobulin E (
IgE) levels were detected by ELISA. Furthermore, lung
collagen contents, α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) expression in the airway were assessed by
hydroxyproline assay, immunohistochemistry, and Western blot analysis, respectively. GSPE administration significantly suppressed airway resistance as well as reduced the amount of inflammatory cells, especially the eosinophil count, in BALF. Additionally, the GSPE treatment markedly decreased
interleukin (IL)-4,
IL-13, and
vascular endothelial growth factor (
VEGF) levels in BALF in addition to the total serum
IgE levels. A histological examination demonstrated that GSPE significantly ameliorated
allergen-induced lung eosinophilic
inflammation and decreased PAS-positive epithelial cells in the airway. The elevated
hydroxyproline contents, lung α-SMA contents, and TGF-β1
protein expression that were observed in the OVA mice were also inhibited by GSPE. In conclusion, GSPE could inhibit airway
inflammation and
airway remodeling in a murine model of chronic
asthma, thus providing a potential treatment for
asthma.