Fig 2: Ovalbumin sensitization and challenge results in increased NGF expression levels in mice. (A) Relative expression of NGF in the lungs was determined using western blot analysis (n=4). (B) NGF protein concentration in the serum was analyzed using an ELISA (n=7). Data are expressed as the mean ± standard deviation of individual groups. *P<0.05, vs. control group; ?P<0.05, vs. asthma and control IgG groups. NGF, nerve growth factor; IgG, immunoglobulin G.

Fig 3: NGF neutralization reduces the proportion of lung CD103+ DCs in asthmatic mice. (A) Expression levels of CD103 in the lung DCs were determined using flow cytometry. Representative data from one of the three replicate experiments are shown. (B) Histograms of compiled data. Data are expressed as the mean ± standard deviation (n=3). (C) Correlation between the proportion of lung CD103+ DCs and the expression levels of NGF in the serum of the various groups of mice (n=12; R=0.781; P<0.01). *P<0.05, vs. control group; ?P<0.05, vs. asthma and control IgG groups. NGF, nerve growth factor; IgG, immunoglobulin; DCs, dendritic cells; CD, cluster of differentiation.

Fig 4: NGF neutralization attenuates airway hyperreactivity, airway inflammation and the T helper 2 response in asthmatic mice. Mice were sensitized via an intraperitoneal injection of 20 µg ovalbumin (OVA) and 1 mg aluminum hydroxide hydrate in 500 µl saline on days one and eight. From day 21, the mice were challenged with 5% OVA for five consecutive days. At 24 h following the last OVA challenge, mice were anesthetized and the airway responsiveness to methacholine was analyzed. (A) Changes in mice airway resistance (RL) in response to methacholine exposure. Data are expressed as a percentage above baseline (normal saline-induced RL) and presented as the mean ± standard deviation (n=7). (B) Representative photomicrographs of hematoxylin and eosin-stained lung sections from the mice (magnification, ×100). (C) Peribronchial inflammation scores of the mice; peribronchial inflammation of four mice from each group were analyzed and scored as follows: 0, normal; 1, few cells observed; 2, a ring of inflammatory cells one cell layer deep; 3, a ring of inflammatory cells 2–4 cells deep; and 4, a ring of inflammatory cells >4 cells deep. (D) Serum expression levels of IL-4 and IFN-? in the mice were detected using an ELISA. Data are presented as the mean ± standard deviation (n=7). *P<0.05, vs. control group; ?P<0.05, vs. asthma and control IgG groups. NGF, nerve growth factor; IgG, immunoglobulin G; IFN, interferon; IL, interleukin.