慢性阻塞性肺疾病大鼠肺组织细胞凋亡和增殖的变化

The changes of apoptosis and proliferation of pulmonary tissue in chronic obstructive pulmonary disease rats

目的 观察慢性阻塞性肺疾病(COPD)大鼠肺组织细胞凋亡和增殖的变化规律,探讨细胞凋亡在COPD发病中的意义。方法 33只Wistar大鼠随机分为 3组:正常对照组 (NC组 ),烟雾暴露 1个月组(COPD 1组),烟雾暴露 2个月组(COPD-2组)。观察肺组织病理学变化和支气管肺泡灌洗液(BALF)中白细胞计数和分类。利用脱氧核糖核酸末端转移酶介导的dUTP缺口末端标记(TUNEL)技术和增殖细胞核抗原(PCNA)免疫组化法对大鼠肺实质凋亡细胞、增殖细胞的阳性细胞率(AI、PI)进行检测。结果 烟雾暴露大鼠支气管黏膜和肺实质均有大量炎细胞浸润,BALF中白细胞总数和中性粒细胞数均显著高于NC组,COPD-2组大鼠出现明显肺气肿改变。COPD-1和COPD-2组大鼠气道上皮细胞、肺泡上皮细胞和血管平滑肌细胞的AI分别为 [ ( 36.2±8.5 )%、( 32.7±6.4)%、(16. 1±7.2 )% ]和 [ ( 39.5±9.3 )%、( 37.3±7.6 )%、( 21.4±6.5 )% ];与NC组 [ ( 5.8±1 .7)%、(6.1±2.3)%、(4.9±1.4)% ]比较差异均有统计学意义 (P均 <0.01);COPD-1和COPD-2组PI分别为 [ ( 33.4±6. 3 )%、( 30.1±4.6 )%、( 28.4±6.3 )%, ( 35.5±9.8 )%、( 33.2±7.7 )%、(34.5±6.7)% ],显著高于NC组[ (7.4±2.3 )%、( 5.2±2.1 )%、( 4.4±1.8 )%,P均 <0.01 ]。且COPD

Objective To observe the changes of apoptosis and proliferation of pulmonary tissue cells in rats with chronic obstructive pulmonary disease(COPD). Methods The rat model of COPD was established by exposure to cigarette smoking. Thirty-three Wistar rats were randomly divided into a normal control(NC) group,a smoking inhalation for 1 month(COPD-1) group and a smoking inhalation for 2 month(COPD-2) group. Pathologic changes of lung tissues and inflammatory cell differentials were studied. Immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) methods were carried out to examine the percentage of positive cells and distribution of apoptotic cells and proliferating cells in the lung tissue. Results Significant increases in total leukocyte numbers and neutrophils in the bronchoalveolar lavage were found in the COPD groups as compared to NC group. Two months after smoking exposure,enlargement of airspaces distal to the terminal bronchiole,destruction of alveolar walls,and loss of the alveolar unit were observed. The percentage of apoptotic cells of airway epithelium,alveolar wall cell and vascular smooth muscle cells were (36.2±8.5)%,(32.7±6.4)%,(16.1±7.2)% in COPD-1 group;(39.5±9.3)%,(37.3±7.6)%,(21.4±6.5)% in COPD-2 group;the difference being significant(all P<0.01),as compared with NC group[(5.8±1.7)%,(6.1±2.3)%,(4.9±1.4)%]. The percentage of proliferative cells of airway epithelium,alveolar wall cell and vascular smooth muscle cells were (33.4±6.3)%,(30.1±4.6)%,(28.4±6.3)% in COPD-1 group;(35.5±9.8)%,(33.2±7.7)%,(34.5±6.7)% in COPD-2 group;the difference being significant(all (P<0.01),)as compared with NC group[(7.4±2.3)%,(5.2±2.1)%,(4.4±1.8)%]. The numbers of apoptotic and proliferating cells were significantly higher in the COPD-2 group than those in the COPD-1 group(all P<0.01). The ratio of proliferative index(PI)/apoptotic index(AI) of the pulmonary tissue cells were also different. The ratio of PI/AI of airway epithelium in COPD-1 and COPD-2 group[(0.82±0.13)%,(0.78±0.24)%] was much lower than NC group[(1.12±0.23)%,P<0.05];The ratio of PI/AI in small pulmonary vessels in the COPD groups[(1.55±0.25)%,(1.47±0.28)%] was significantly higher than NC group[(0.92±0.05)%,P<0.05]. Conclusion The changes of apoptosis and proliferation of pulmonary tissue in COPD rats might contribute to the pathogenesis of COPD.