神经生长因子在实验性支气管哮喘小鼠发病中上调磷脂酶C-γ表达

Upregulation of nerve growth factor on expression of phospholipase C-γ in experiment asthmatic mice

目的研究支气管哮喘（简称哮喘）小鼠下呼吸道及内脏感觉传人部位磷脂酶C-γ（PLC-γ）的表达，及神经生长因子（nervegrowthfactor，NGF）对PLC-γ在上述部位的调节作用，探讨NGF介导的信号转导通路在哮喘发病机制中的作用。方法BABL／C30只，按随机数字表法分为正常对照组、哮喘组及NGF阻断组。利用AniRes2005肺功能仪测BABL／c小鼠气道阻力，应用免疫组织化学方法和免疫印记法（Westernblotting），观察PLC-γ在哮喘小鼠下呼吸道及内脏感觉传人部位的表达及NGF被阻断后PLC-γ表达水平的变化，Metamoph图象分析系统对结果进行分析。结果气道阻力检测结果显示，哮喘组小鼠较正常对照组气道阻力明显增高（P〈0．01），NGF阻断组气道阻力均较哮喘组明显降低（P〈0．01）。免疫组织化学结果显示PLC在NGF阻断组小鼠肺组织（0．273±0．018），C7～T5段脊神经节（0．158±0．012），以及相应节段的脊髓后角内（0．168±0．022）表达明显低于哮喘组（0．423±0．023，0．351±0．018，0．368±0．014）（P〈0．01）。Westernblotting结果显示NGF阻断组肺（0．921±0．014）及C7～T5节段脊髓（0．835±0．023）PlC-γMOD值与pactinMOD值的比值明显低于哮喘组（1．476±0．017，1．251±0．019）（P〈0．01）。结论PLC-γ在哮喘小鼠肺、C7～T5节段脊神经节及相应的脊髓后角过表达，NGF上调哮喘上述部位PLC-γ的表达，提示NGF可通过调节肺内及内脏传入部位PLC的表达参与哮喘发病过程。

Objective To study the expression of phospholipase C-γ（PLC-γ） in lower respiratory tract and visceral sensation afferent site of asthmatic mice and the regulatory effect of nerve growth factor（NGF） on PLC-γ in above-mentioned site,to explore the function of NGF mediated signal pathway in the asthmatic pathogenesis. Methods Thirty BALB/c mice were randomly divided into normal control group, asthmatic group,anti-NGF group on average. The airway resistance of mice was measured by AniRes 2005 lung function meter. By means of immunobistochemistry and Western blotting to investigate the changes of PLC-γ immunoreactivity and the regulatory effect of NGF in the lower respiratory tract and viscerosensory afferent sites of the asthmatic mice model and analyzed by Metamoph anaysis system. Results Airway resistance measurement showed： increased airway resistance to methacholine was observed in the asthmatic group compared with the normal control group, but decreased in anti-NGF group compared with the asthmatic group（ P 〈0.01）. The expression of PLC-γ was decreased significantly in lower respiratory tract （0. 273 ± 0.018） and visceral sensory afferent sites[C7-T5 spinal ganglia （0. 158 ± 0.012） and the corresponding posterior horn of the spinal cord （0. 168±0. 022）] of the anti-NGF group compared with the asthmatic mice model （0. 423± 0. 023,0. 351 ±0. 018,0. 368±0. 014） （ P 〈0.01）. The result of Western blotting shows that the ratio between PLC-γ MOD value of lung （0. 921 ±0. 014）, C7-T5 spinal cord （0. 835 ±0. 023 ） and β-actin MOD value in anti-NGF group is obviously decreased to that of the asthmatic group（1. 4764±0. 017, 1. 251 ± 0. 019）. Conclusions There is overexpression of PLC-γ in the lungs, C7-T5 spinal ganglia and corresponding spinal dorsal horn. NGF upregulates the expression of PLC-γ in the above-mentioned site. This finding suggests that PLC-γ might take part in the mechanism of NGF mediated asthma.