核因子-κB在慢性阻塞性肺疾病大鼠肺内的表达及泼尼松对其的影响

Expression of nuclear factor kappa B in rat model of chronic obstructive pulmonary disease and the effect of glucocorticoid

目的探讨核因子κB(NF-κB)在慢性阻塞性肺疾病(COPD)发病机制中的作用及糖皮质激素在COPD中的治疗价值。方法Wistar大鼠24只随机分为3组:对照组、COPD组和激素组,每组8只大鼠。采用单纯熏香烟法建立COPD模型,激素组于熏香烟前予泼尼松隔日灌胃。支气管肺泡灌洗(BAL),测定支气管肺泡灌洗液(BALF)中细胞总数、中性粒细胞绝对计数和百分比,并对肺组织切片行HE染色观察形态学改变,采用图像分析系统定量测定肺平均内衬间隔(MLI)、平均肺泡数(MAN)和肺泡腔面积与总面积比(PAA)。对大鼠肺组织切片采用免疫组织化学法观察3组大鼠肺组织NF-κB表达的变化。结果COPD组MLI和PAA均较对照组增高,差异有统计学意义(P<0.01),泼尼松干预后下降(与COPD组比较,P<0.01或0.05),而COPD组MAN低于对照组,治疗后增高,差异有统计学意义(P<0.01或0.05)。与对照组比较,COPD组BALF中白细胞总数[(1.64±0.12)×108/L比(5.76±0.29)×108/L]、中性粒细胞绝对计数[(0.099±0.065)×108/L比(1.26±0.25)×108/L]均增高,差异有统计学意义(P<0.01)。泼尼松干预后上述指标均下降(P<0.01)。COPD组细支气管上皮细胞NF-κB核染色阳性细胞百分比为(29.02±1.25)%,与正常组[(12.17±1.13)%]比较,差异有统计学意义(P<0.01);激素组为(19.23±1.18)%,与COPD组比较,差异亦有统计学意义(P<0.01)。结论NF-κB与COPD的气道炎症密切相关,泼尼松治疗可以通过调节NF-κB的表达,抑制粒细胞趋化和脱颗粒,增加中性粒细胞弹性蛋白酶的抑制活性,从而减轻气道炎症及其对气道的损害,延缓COPD的进展。

Objective To exlore the role of nuclear factor kappa B（NF-κB） in the pathogenesis of chronic obstructive pulmonary disease （ COPD ） and the therapeutic effects of glucocorticoid. Methods Twenty-four Wistar rats were randomly divided into three groups, ie. normal control, COPD model and prednisone preventive treatment group. Rat COPD model was established by exosing the rats to cigarette smoke daily. Prednisone was given through stomachal injection on alternate days. After COPD model was set up,bronchoalveolar lavage （BAL） was performed. Total cell counts and neutrophil counts in BALF were exmined. Pathological changes of lung tissue was observed by hematoxlin-eosin staining. The morphological indices of pulmonary emphysema （ MLI, MAN and PAA） was measured by a computerized image analyzer and compared in three groups. NF-κB exression in lung tissues were detected by immunohistochemistry assay. Results Emphysema was confirmed by three morphological indices in COPD model group compared to those of normal control group[ MLI： （97.97 ± 11.10）×10^-6m vs（47.23 ±2. 80） ×10-^6m,MAN： （95. 98 ± 14. 89） ×10^6/m^2 vs （ 164. 21 ±9. 30） ×10^6/m^2 ,PAA： （64 ±5.7）% vs（44 ±2. 7） %, P 〈 0. 01 ]. Total cell counts and neutrophil counts in BALF of COPD model group were significantly higher than those of control group [ （ 5.76 ± 0. 29 ） ×10^8/L vs （ 1.64 ± 0. 12 ） ×10^8/L, （ 1.26 ± 0. 25 ） ×10^8/L vs （ 0. 099 ± 0. 065 ） ×10^8/L, P 〈 0. 01 ]. After the preventive treatment with prednisone,MLI, MAN and PAA were significantly changed [ （57.66 ± 4.62） ×10^-6m vs （97.97 ± 11.10） ×10^-6m,（111. 40 ±16.92） ×10^6/m^2 vs（95.98 ±14.89） ×10^6/m^2,P 〈0.01;（58 ±6. 1）% vs （64 ± 5.7 ）%, P 〈 0. 05 ], which indicated that airway inflammation and emphysematous injury in preventive treatment group were milder than those of COPD model.Total cell counts and neutrophil counts in BALF were found in preventive treatment group as compared to those of COPD model [ （3. 18 ± 0.29 ） ×10^8/L vs（5.76 ± 0. 29） ×10^8/L, （0. 57 ± 0. 12） ×10^8/L vs（ 1.26 ± 0. 25 ） ×10^8/L,P 〈 0. 01 ]. The percentage of positive cells of NF-κB nuclear staining in bronchiolar epithelial cells was significantly increased in the COPD group than that in the control group[ （29. 02 ± 1.25）% vs（ 12. 17 ± 1.13）% ,P 〈 0. 01 ] ,but was significantly decreased in the preventive treatment group[ （19. 23 ± 1.18）% vs（29.02 ± 1.25 ） %, P 〈 0. 01 ]. Conclusions NF-κB may be responsible for the persistence and amplification of inflammation in COPD through neutrophil recruitment and activation. Prednisone may suppress airway inflammation in COPD by inhibiting NF-κB.