摘要目的 观察神经生长因子(NGF)及其酪氨酸激酶A(TrkA)受体在COPD大鼠肺泡巨噬细胞的表达变化.方法 40只雄性SD大鼠,随机分为对照组和COPD组,每组20只.采用6个月单纯烟熏法建立COPD大鼠模型,并检测肺功能,HE染色观察肺组织病理变化.从支气管肺泡灌洗液中分离纯化出肺泡巨噬细胞,用酶联免疫吸附法测定肺泡巨噬细胞培养液的上清液中NGF蛋白表达,激光共聚焦法鉴定肺泡巨噬细胞以及半定量检测肺泡巨噬细胞的TrkA蛋白表达.实时荧光定量PCR法检测肺泡巨噬细胞的NGF mRNA及TrkA mRNA表达.两组间比较采用单因素方差分析,组间比较采用t检验.结果 COPD组大鼠肺顺应性为(0.15 ±0.03) ml/cm H2O(1 cm H2O =0.098kPa),每分通气量为(0.045±0.004)L,均显著低于对照组的(0.42±0.05) ml/cm H2O和(0.102±0.010)L,差异均有统计学意义(t值分别为9.46和12.99,均P＜0.01)；气道阻力为(0.038±0.004)cm H20·L-1·S-1,显著高于对照组的(0.016±0.002)cm H2O·L-1·s-1,差异有统计学意义(t=11.55,P＜0.01).肺组织病理显示,COPD组大鼠肺泡壁变薄,肺泡间隔破裂,肺泡腔不规则扩大,部分融合形成肺大疱,肺气肿形成.COPD组NGF蛋白表达量为(3.79±1.52) ng/L,显著高于对照组的(0.94±0.27) ng/L,差异有统计学意义(t=4.13,P ＜0.05).COPD组TrkA蛋白平均荧光强度值(19.5±1.5)显著高于对照组(11.2±1.9),差异有统计学意义(t=7.95,P＜0.05).COPD组NGF和TrkA的mRNA表达量(24.8±6.0和9.0±3.3)显著高于对照组(1.0±0.2和1.0±0.4),差异均有统计学意义(t值分别为8.48和5.16,均P＜0.05).结论 COPD组肺泡巨噬细胞高表达NGF及其TrkA受体,提示NGF及其TrkA受体可能介导肺泡巨噬细胞参与COPD的发病过程.

abstractsObjective To observe the expressions of nerve growth factor (NGF) and its tyrosine kinase A (TrkA) receptor on alveolar macrophage in a rat model of chronic obstructive pulmonary disease (COPD).Methods Forty healthy male SD rats were randomly divided into a control group and a COPD group.The COPD model was established by exposing the rats to cigarette smoke for 6 months,and lung function changes were measured. Lung histopathological changes were detected by HE staining. The expression of NGF protein in the supernatant of alveolar macrophage (AM) culture medium was detected by ELISA.Confocal microscopy was used to identify the separation and purification of AM from bronchoalveolar lavage fluid,and to detect semi-quantitatively the expression of TrkA receptor on AM. NGF and its TrkA receptor at the mRNA level were evaluated by real-time PCR.The differences among groups were calculated by one way ANOVA,and comparison between groups was made by t test.Results Significant decrease of pulmonary compliance [(0.15 ± 0.03) ml/cm H2O ( 1 cm H2O =0.098 kPa)] and minute ventilation [(0.045 ±0.004) L],and significant increase of airway resistance [(0.038 ±0.004) cm H2O · L-1 s-1] were found in the COPD group compared with the control group [(0.42 ± 0.05) ml/cm H2O and (0.102±0.010) Land (0.016±0.002) cm H2O · L-1 · s-1,t=9.46-12.99,respectively,all P＜0.01]. Alveolar wall thinning, alveolar septa breakdown, alveolar enlargement and emphysema were significant in the COPD rats.The expression of NGF protein in the supernatant of AM culture medium was enhanced in the COPD group [(3.79 ± 1.52) ng/L] compared with the controls [(0.94 ±0.27) ng/L,t =4.13,P ＜0.05].Mean fluorescence intensity of TrkA protein on AM in the COPD group ( 19.5 ± 1.5)was higher than that in the control group ( 11.2 ± 1.9,t =7.95,P ＜ 0.05).The expressions of NGF and TrkA at mRNA level in the COPD group ( 24.8 ± 6.0 and 9.0 ± 3.3 ) were increased compared with the control group ( 1.0 ± 0.2 and 1.0 ± 0.4,t =8.48 and 5.16,all P ＜ 0.05 ).Conclusions The expressions of NGF and its TrkA receptor on AM in COPD group were increased,indicating that NGF and its TrkA receptor might be involved in the pathogenesis of COPD mediated by AM.