Objective: To investigate the regulatory effect of nerve growth factor (NGF) on Ras-MAPK signal transduction pathway in neurogenic inflammation of asthma.
Methods: Thirty-six Sprague-Dawley rats were randomly divided into 3 groups (control group, asthma group and anti-NGF group). The asthmatic model was established by ovalbumin inhalation and injection. The protein expressions of pan-Ras, pERK and c-fos in the dorsal root ganglion and lung of the asthma group and the control group were examined by immunohischemical method. Anti-NGF antibody was used to investigate how it affected the protein expression of pan-Ras, pERK and c-fos in the dorsal root ganglion and the lung of the asthma group. PD98059 (the inhibitor of MAPK) and PMA (the enhancer of PKC) were used to culture the NHBEC. Cell extracts were analyzed for pERK, total-ERK and c-fos by Western blot.
Results: The protein expressions of pan-Ras, pERK and c-fos in the lung and dorsal root ganglion of the asthma group were significantly higher than those of the control group (P < 0.01). The protein expressions of pan-Ras, pERK and c-fos were decreased by the anti-NGF treatment (P < 0.01) . The expressions of epithelial pERK and c-fos in the NGF group were significantly higher than those in the control group, and PD98059 could inhibit NGF inducing NHBEC to produce pERK and c-fos. PMA could enhance the effects of NGF.
Conclusion: NGF may play a role in the pathogenesis of neurogenic inflammation in asthma through Ras-MAPK signal transduction pathway.