Abstract:

Objective To determine the expression of neurotrophin-3 (NT-3) and its receptors tyrosine kinase C (TrkC) and p75 pan-neurotrophin receptor (P75NTR) in the lung tissues of rats with asthma. Methods Twenty-eight SD rats aged 4 to 6 weeks were randomized into asthma group (rat asthma model established by sensitization with ovalbumin and challenge, n=16) and normal control group (n=12). Lung tissues of rats in groups rats were obtained for pathological sections, and pathological characteristics of bronchus and lung tissues were observed with HE staining under light microscopy. The expression of NT-3, TrkC and p75NTR mRNA in the lung tissues of two groups of rats was detected by Real-Time PCR, and the correlation among them was analysed. Results Light microscopy revealed that the numbers of lymphocytes and eosinophils surrounding bronchial wall were increased, and there were bronchial airway epithelium shedding, goblet cell hyperplasia and increase of mucous suppository in asthma group, while there was no abnormal findings in the bronchial and alveolar structure in normal control group. The relative expression of NT-3, TrkC and p75NTR mRNA in lung tissues in asthma group was significantly higher than that in normal control group (P＜0.05). Correlation analysis indicated that the expression of NT-3 mRNA was positively related to that of TrkC mRNA (r=0.89, P<0.01) and p75NTR mRNA (r=0.90, P<0.01), and the expression of TrkC mRNA was positively related to that of p75NTR mRNA (r=0.82, P<0.01). Conclusion The expression of NT-3 mRNA increases in lung tissues of rats with asthma induced by sensitization. NT-3 upregulates the expression of TrkC and P75NTR mRNA, enhances the function of NT-3, which may participate in the airway neuronal inflammation in asthma.

Key words: asthma, neurotrophin-3, tyrosine kinase C, p75 neurotrophin receptor