Effect of Th1/Th2 cytokine immune imbalance on the expression of nerve growth factors in asthma / 中南大学学报(医学版)

OBJECTIVE@#To explore the effect of Th1/Th2 cytokines on the expression of nerve growth factor(NGF)in splenic lymphocytes in asthmatic model.@*METHODS@#Four SD rats were sensitized and challenged with ovalbumin to establish an asthmatic model, and the rat splenic lymphocytes were isolated and cultured with ConA. The expressions of NGF mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR), and were observed after the lymphocytes were exogenously added with interferon-gamma(IFN-gamma) or interleukin-4 (IL-4).@*RESULTS@#The lymphocytes of the asthmatic model stimulated by ConA in vitro expressed NGF mRNA in a time-dependent manner. After the lymphocytes had been cultured with IL-4 for 12 h, 24 h, 36 h, and 48 h, 50 microg/L IL-4 upregulated the expressions of NGF mRNA in a time-dependent manner and all the NGF mRNA expressions were significantly higher than the basal values at the same time(all Ps<0.01). After 0, 10, 50, and 100 microg/L IL-4 had been added for 24 h, IL-4 upregulated the expressions of NGF mRNA in a dose-dependent manner and the NGF mRNA expressions were all significantly higher than the values of the lower dose IL-4(all Ps<0.05). After the lymphocytes had been cultured with 10 mug/L IFN-gamma for 0 h, 12 h, 24 h, 36 h, and 48 h, IFN-gamma downregulated the expressions of NGF mRNA in a time-dependent manner and all the NGF mRNA expressions were significantly lower than the basal values at the same time(all Ps<0.01). After 0, 1, 10, and 50 microg/L IFN-gamma have been added for 24 h, IFN-gamma downregulated the expressions of NGF mRNA in a dose-dependent manner and all the NGF mRNA expressions were significantly lower than the values of the lower IFN-gamma dose(all Ps<0.05).@*CONCLUSION@#In the splenic lymphocytes of asthmatic rats, IL-4, one of the Th2 cytokines, can upregulate the expressions of NGF; IFN-gamma, one of the Th1 cytokines, can downregulate the expressions of NGF both in a time-dependent manner and in a dose-dependent manner. Th1/Th2 cytokine immune imbalance may indirectly induce the airway neurogenic inflammation by regulating the NGF mRNA expression.

Regulation effect of nerve growth factor on Ras-MAPK signal transduction pathway in neurogenic inflammation of asthma / 中南大学学报(医学版)

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.

Changes of nerve growth factor and its receptors in the lung tissues in asthmatic rats and their effects on the airway inflammation / 中南大学学报(医学版)

OBJECTIVE@#To determine the expression of nerve growth factor (NGF), tyrosine kinase receptor A (trkA), and pan-neurotrophin receptor (p75) in the lung tissues in asthmatic rats, and to explore their effects on the airway inflammation.@*METHODS@#Thirty-two SD rats were randomly divided into 4 groups: the control, asthma, NGF and anti-NGF groups. The asthmatic model was established by the inhalation and injection of ovalbumin. The total cell count and differential cell count in the bronchoalveolar lavage fluid (BALF) were performed. The pathologic changes in the lung tissues of the 4 groups was detected by HE staining. The NGF mRNA expression in the lung tissues of the asthma and control groups was determined by reverse transcription-polymerase chain reaction (RT-PCR). The changes of trkA and p75 mRNA expressions in the lung tissues in the 4 groups were also investigated by RT-PCR.@*RESULTS@#Compared with the control group, the BALF total cell, the BALF eosinophils (Eos), and the BALF lymphocytes (Lyms) significantly increased (All P <0. 001) in the asthma group; and the lung tissues of the asthma group had more infiltrating inflammatory cells. Not only the expression of NGF mRNA, but also its receptors trkA and p75 mRNA in the lung tissues were significantly higher in the asthma group than those in the control group (All P < 0.01). Positive correlation was found between the expression of NGF mRNA and the BALF total cell, the BALF Lyms in the asthma group. Compared with the asthma group, the total cell, the Eos, and the lyms in BALF in the NGF group significantly increased (All P < 0.01), and the lungs of the NGF group had apparent inflammatory changes. The expre-ssions of p75 and trkA mRNA were enhanced significantly (All P < 0.05). Compared with the asthma group, the total cell, the Eos, and the lyms in BALF in the anti-NGF group significantly decreased (All P < 0.001), and the lungs of the anti-NGF group showed alleviative inflammatory changes. The expre-ssions of p75 and trkA mRNA significantly decreased (All P < 0.01).@*CONCLUSION@#In lungs of asthmatic rats, the elevated expression of NGF mRNA is closely related to the airway inflammation. NGF can upregulate the expressions of p75 and trkA mRNA in asthmatic rats, and then may promote their role in the airway neuronal inflammation in asthma.