分析人脐带间充质干细胞(human umbilical cord mesenchymal stem cells, HU-MSCs)对慢性阻塞性肺疾病(chronic obstructive pulmonary disease, COPD)小鼠的治疗效果及作用机制。

采用烟熏联合脂多糖法构建COPD小鼠模型，取40只C57BL/6J雄性小鼠随机分为对照组10只和COPD组30只，对照组采用常规饲养，COPD组采用烟熏联合脂多糖(LPS)鼻内滴注。观察小鼠生存率和体质量变化；HE染色观察小鼠肺组织病理学改变。收集P5代HU-MSCs，按5×10⁶个细胞/ml制作细胞悬液，输注小鼠。对照组经尾静脉注射200 μl生理盐水Normal saline(NS)；选取COPD组20只小鼠，随机分为COPD+NS组10例，经尾静脉注射200 μl NS；COPD+HU-MSCs组10例经尾静脉注射200 μl HU-MSCs悬液。观察HU-MSCs对COPD小鼠的治疗效果。移植后第30天，留取小鼠血清、支气管肺泡灌洗液标本和肺组织标本，应用ELISA检测每组小鼠血清、肺泡灌洗液中TNF-α、IL-1和IL-10，SOD和MDA与MMP-9、TIMP-1，HE染色和Masson染色观察每组小鼠肺组织病理学改变。

COPD组小鼠一般情况逐渐变差并出现咳嗽，体质量下降(P<0.05)，肺组织病理切片显示COPD改变。移植HU-MSCs后，COPD+HU-MSCs组小鼠体质量快速增加(P<0.05)，小鼠血清和BALF中TNF-α和IL-1水平降低(P<0.05)，IL-10水平提高(P<0.05)；SOD含量增加(P<0.05)，MDA含量降低对MMP-9、TIMP-1水平无影响(P>0.05)。肺组织病理切片显示，小鼠肺泡数目增多，肺泡大小不一有所恢复，肺泡间隔较厚且连续，未见明显胶原纤维增生。未观察到明显不良反应，每组实验小鼠无死亡。

HU-MSCs移植治疗COPD小鼠可改善症状，快速恢复小鼠体质量，修复受损肺泡组织，安全和有效。HU-MSCs可能抑制COPD小鼠的氧化损伤、减轻肺部炎症反应。

To investigate the therapeutic effect of human umbilical cord mesenchymal stem cells (HU-MSCs) on chronic obstructive pulmonary disease(COPD) mice and initially explore its mechanism.

In order to establish a mouse model of COPD constructed by smoking combined with lipopolysaccharide method. In the modeling part, 40 C57BL/6J male mice were randomly divided into normal control group (n=10) and COPD group (n=30), feeding conventionally or giving intranasal administration of smoking combined with lipopolysaccharide (LPS). The survival rate and body weight of mice were assessed, the pathological changes of lung were observed by HE staining. The HU-MSCs at passage 5 were collected, and cell suspension was prepared containing 5×10⁶ cells /ml and transfused into mice by tail vein. The mice were divided into: normal control group was set as: (1) normal control group (n=10, 200 μl normal saline, NS); Twenty constructed COPD mice were randomly divided into: (2) COPD+ NS group (n=10, 200 μl NS); (3)COPD+ HU-MSCs group (n=10, 200 μl HU-MSCs suspension, containing 1×10⁶ cells). Then the therapeutic effect of HU-MSCs on COPD mice were assessed. On the 30 th day after transplantation, serum, bronchoalveolar lavage fluid and lung tissue samples of mice were collected. Besides, the concentration of TNF-α, IL-1 and IL-10, SOD and MDA, MMP-9 and TIMP-1 in serum and alveolar lavage fluid of mice in each group were detected by ELISA, and the lung histo pathologye were detected by HE and Masson staining.

Compared with normal control group, the COPD group showed a deteriorated general condition, cough, and decreased body weight (P<0.05). The pathological sections of lung tissue showed changes in COPD.The COPD+ HU-MSCs group got faster weight gain (P<0.05), decreased TNF-α and IL-1 concentration (P<0.05), and increased IL-10 concentration (P<0.05) in serum and BALF after transplantation. Meanwhile, SOD concentration was increased (P<0.05) and MDA content was decreased. The levels of MMP-9 and TIMP-1 were not affected (P>0.05). The pathological sections of lung tissue showed increased alveoli number, recovered alveolar of varied sizes, thick and continuous alveolar septum and no obvious collagen fiber hyperplasia. No obvious adverse reactions or death were observed in each group.

HU-MSCs transplantation is safe and effectively improve the symptoms of COPD mice, restore weight rapidly and repair damaged alveolar tissue. It may act through inhibiting oxidative damage and alleviating lung inflammation.