慢性阻塞性肺疾病大鼠血清及肺组织中肺表面活性蛋白D的水平变化及意义

目的通过测定肺表面活性蛋白D（SP-D）在慢性阻塞性肺疾病（COPD）大鼠肺组织及血清中的含量变化,探讨SP-D与COPD发病的关系。方法采用烟熏加气管内注入内毒素脂多糖（LPS）的方法建立大鼠COPD模型。将雄性SD大鼠随机分为对照组、内毒素组和COPD组,每组10只。HE染色观察大鼠肺、支气管的病理改变,定量检测肺平均内衬间隔（MLI）及平均肺泡数（MAN）以评估肺气肿程度。酶联免疫吸附实验（ELISA）检测大鼠血清SP-D含量。Western-blot及免疫组化方法检测大鼠肺组织SP-D含量变化。结果 COPD组大鼠肺、支气管的HE染色下病理变化符合COPD的典型病理改变。COPD组大鼠MLI较对照组明显增宽（80±5）μm/个比（49±2）μm/个,P〈0.05],MAN较对照组明显减少（274±13）个/mm2比（406±12）个/mm2,P〈0.01）;内毒素组MLI、MAN与对照组比较无显著差异（P〉0.05）。对照组、内毒素组和COPD组大鼠血清SP-D含量分别为（42.14±2.52）ng/mL、（49.59±2.81）ng/mL和（53.21±4.17）ng/mL,肺组织SP-D含量分别为0.39±0.01、0.56±0.01和0.63±0.01。内毒素组及COPD组大鼠血清和肺组织中SP-D含量均较对照组明显升高（P〈0.05）,而COPD组又显著高于内毒素组（P〈0.05）。3组血清SP-D水平与肺组织中SP-D含量均呈正相关（r值分别为0.93、0.94和0.93,P〈0.01）。结论 COPD组大鼠血清及肺组织中SP-D含量明显升高,并且血清及肺组织中SP-D水平呈显著正相关。COPD大鼠血清及肺组织中SP-D水平的研究为将SP-D作为COPD的生物标记物提供一定依据。

Changes of Pulmonary Surfactant Protein D in Serum and Lung Tissue of Rats with Chronic Obstructive Pulmonary Disease

Objective To investigate the relationship of pulmonary surfactant protein D(SP-D) with chronic obstructive pulmonary disease(COPD) by measuring SP-D level in serum and lung tissue of rats with COPD.Methods The rat COPD model was established by passive smoking as well as intratracheal instillation of lipopolysaccharide(LPS).Thirty male SD rats were randomly divided into a control group,a LPS group,and a COPD group(n=10 in each group).The pathologic changes of lung tissue and airway were observed under light microscope by HE staining.Emphysema changes were evaluated by mean linear intercept(MLI) of lung and mean alveolar number(MAN).The level of SP-D in serum was measured by enzyme-linked immunosorbent assay(ELISA).The expression of SP-D in lung tissue was detected by Western-blot and immunohistochemistry.Results The MLI obviously increased,and MAN obviously decreased in the COPD group compared with the control group(P<0.05).There was no significant difference in the MLI and MAN between the LPS group and the control group(P>0.05).The serum SP-D level was(49.59±2.81)ng/mL and(53.21±4.17)ng/mL in the LPS group and the COPD group,which was significantly higher than that in the control group (42.14±2.52)ng/mL](P<0.05).The expression of SP-D in lung tissue was 0.56±0.01 and 0.63±0.01 in the LPS group and the COPD group,which was also obviously stronger than that in the control group(0.39±0.01)(P<0.05).Meanwhile the SP-D levels in serum and lung tissue were higher in the COPD group than those in the LPS group(P<0.05).The levels of SP-D between serum and lung tissue were positively correlated in all three groups(r=0.93,0.94 and 0.93,respectively,P<0.01).ConclusionBoth the SP-D level in serum and in lung tissue incr ease significantly in COPD rats and correlate well each other,which suggests that SP-D may serve as a bio marker of COPD.