骨髓间充质干细胞对博来霉素致大鼠肺纤维化形成的影响

目的通过观察骨髓间充质干细胞（MSC）对博来霉素致大鼠肺纤维化动物模型的影响，探讨治疗肺纤维化的新方法。方法体外分离、培养雄性6周龄SD大鼠的骨髓MSC。将48只雌性SD大鼠随机分为6组，第1—5组经气管注入5．0mg／kg博来霉素0．3Tnl，第1和第3组分别于博来霉素注射第1天和第7天经尾静脉注入雄性大鼠MSC液0．2ml（细胞数为2．5×10^6个）；第2和第4组分别于博来霉素注射第1天和第7天经尾静脉注入等量的磷酸缓冲液0．2ml；第5组作为模型阳性对照，注射博来霉素后未给予其他处理；第6组作为模型阴性对照，经气管注入等量生理盐水0．3ml代替博来霉素，未给予其他处理。于实验第28天统一处死大鼠，留取肺组织行病理学检查、羟脯氨酸含量测定；提取肺组织的DNA，通过聚合酶链反应（PCR）-琼脂糖电泳法检测雄鼠的性别决定基因（sry基因），以判断外源给予的MSC是否在雌性大鼠肺组织中存在。结果在博来霉素致肺损伤第1天和第7天给予MSC干预治疗后的大鼠肺脏病理改变均较对照组减轻，肺纤维化程度评分分别为（1．0±0．2）分、（2．5±0．5）分和（1．6±0．5）分、（2．3±0．8）分；肺组织羟脯氨酸含量分别为（83±17）μg／mg、（96±20）μg／mg和（123±32）μg／mg、（127±34）μg／mg，在博来霉素致肺损伤第1天较第7天给予MSC其作用更明显。PCR检测结果显示，在博来霉素致肺损伤第1天给予MSC组的大鼠肺组织可以检测到sry基因。结论外源给予的MSC可以减轻肺纤维化的形成，在肺损伤早期给予MSC干预的疗效更好。

Effects of bone marrow mesenchymal stem cells on bleomycin induced pulmonary fibrosis in rats

OBJECTIVE: To study the effects of bone marrow mesenchymal stem cells (MSC) on pulmonary fibrosis. METHODS: Bone marrow MSC were harvested from 6 week old male SD rats. Forty-eight female SD rats were randomly divided into six groups. The pulmonary fibrosis models were made by intratracheal instillation of bleomycin (5 mg/kg in 0.3 ml normal saline). The normal controls received intratracheal instillation of NS instead of bleomycin. On the 1st and 7th day after bleomycin administration, the rats received MSC infusion or a same amount of phosphate buffer solution (PBS) as controls via the tail vein, respectively. The rats were sacrificed by the 28 day of experiment, and the pathologic changes and hydroxyproline contents of the lung tissues were investigated. The sry gene of Y chromosome was detected by polymerase chain reaction (PCR). RESULTS: For rats receiving MSC on the 1st and 7th day after bleomycin administration, the lung fibrotic scores were 1.0 +/- 0.2 and 1.6 +/- 0.5, respectively, significantly decreased as compared with rats receiving no MSC (2.5 +/- 0.5 & 2.3 +/- 0.8, respectively). The hydroxyproline contents of lung tissue were (83 +/- 17) microg/mg and (96 +/- 20) microg/mg, also significantly decreased as compared with rats receiving no MSCs [(123 +/- 32) microg/mg & (127 +/- 34) microg/mg, respectively]. Earlier administration of MSCs resulted in more significant improvement of lung injury. The sry gene (322 bp) was detected in lungs of female rats receiving MSC on the first day of bleomycin induced lung injury. CONCLUSIONS: MSC may be involved in the repair of lung injury, especially in the early stage. MSCs are effective in preventing bleomycin induced lung injury and fibrosis.