The central glial cell line-derived neurotrophic factor (GDNF) regulates pulmonary function in asthmatic rats

Asthma is a common chronic inflammatory disease of the airway, but the mechanism is still not fully understood. This study aimed to investigate the effect of glial cell line-derived neurotrophic factor (GDNF) on asthma attacks. An asthmatic rat model was established. GDNF expression in the airway and brain was observed by immunohistochemistry (IHC), and the concentration of GDNF in bronchoalveolar lavage fluid (BALF) was detected by enzyme-linked immunosorbent assay (ELISA). After injection of GDNF and its antibody into the lateral ventricle of asthmatic rats, the pulmonary function was recorded, and the levels of interferon-γ (IFN-γ) and interleukin-4 (IL-4) in BALF were tested. GDNF expressions were increased significantly in the lung tissues of asthmatic rats. In the central nervous system (CNS), GDNF-positive immunoreactive substances were observed in multiple brain regions, including the medial amygdala (MeA), paraventricular nucleus (PVN), cortex, and nucleus of solitary tract (NTS). After injection of GDNF into the lateral ventricles of asthmatic rats, the symptoms of asthma and airway inflammation were significantly aggravated, which could be improved by injection of GDNF antibody into the lateral ventricles. GDNF expression is increased in the lung and brain in asthmatic rats. During an asthma attack, the increased GDNF expressions in the rat brain remarkably aggravate the asthmatic symptoms.