Ouyang Ruo-yun, Hu Cheng-ping, Zhu Jin-qi, Huang Xin-gang
Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha 410008, China.
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2005 Dec;30(6):660-5.
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.
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.
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).
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.
检测神经生长因子（NGF）、酪氨酸激酶受体A（trkA）及泛神经营养因子受体（p75）在哮喘大鼠肺组织中的表达，探讨其对气道炎症的影响。
将32只SD大鼠随机分为4组：对照组、哮喘组、NGF组和抗NGF组。采用卵清蛋白雾化吸入及注射的方法建立哮喘模型。进行支气管肺泡灌洗液（BALF）中细胞总数及分类计数。HE染色观察4组大鼠肺组织的病理变化。采用逆转录聚合酶链反应（RT-PCR）检测哮喘组和对照组大鼠肺组织中NGF mRNA的表达。同时用RT-PCR检测4组大鼠肺组织中trkA和p75 mRNA表达的变化。
与对照组相比，哮喘组BALF中细胞总数、嗜酸性粒细胞（Eos）及淋巴细胞（Lyms）均显著增加（均P<0.001）；哮喘组肺组织有较多炎性细胞浸润。哮喘组肺组织中NGF mRNA及其受体trkA和p75 mRNA的表达均显著高于对照组（均P<0.01）。哮喘组中NGF mRNA表达与BALF中细胞总数、Lyms呈正相关。与哮喘组相比，NGF组BALF中细胞总数、Eos及Lyms均显著增加（均P<0.01），NGF组肺组织有明显炎性改变，p75和trkA mRNA表达显著增强（均P<0.05）。与哮喘组相比，抗NGF组BALF中细胞总数、Eos及Lyms均显著减少（均P<0.001），抗NGF组肺组织炎性改变减轻，p75和trkA mRNA表达显著降低（均P<0.01）。
哮喘大鼠肺组织中NGF mRNA表达升高与气道炎症密切相关。NGF可上调哮喘大鼠p75和trkA mRNA的表达，进而可能促进其在哮喘气道神经源性炎症中的作用。
