骨髓间充质干细胞治疗大鼠百草枯中毒急性肺损伤的作用

Effect of mesenchymal stem cell used on prevention and treatment for acute pulmonary injury induced by paraquat poisoning in rats

目的 观察骨髓间充质干细胞（MSCs）防治大鼠百草枯（PQ）中毒急性肺损伤的作用及可能机制.方法 80只SPF级Wistar大鼠随机（随机数字法）分为4组,每组20只：肺损伤组、MSCs治疗组、MSCs对照组和正常对照组.腹腔注射质量分数为20%的百草枯18 mg/kg制备大鼠中毒模型,正常对照给予磷酸缓冲液（PBS）.取第4代MSCs,加入携带增强型绿色荧光蛋白基因的腺病毒载体Ad5-EGFP,转染成功后,在染毒后4 h经尾静脉注射入大鼠体内,分别在给予MSCs后1 d,3 d,7 d,28 d时随机处死每组大鼠各5只,行肺组织病理切片,荧光倒置显微镜观察骨髓间充质干细胞的迁移,于28 d处死各组大鼠取相应标本,检测肺系数、肺匀浆中羟脯氨酸（HYP）的含量、血清转化生长因子-β1（TGF-β1）,同时行肺组织病理学观察.结果 肺组织病理学观察显示,MSCs治疗组肺纤维化及实变程度较肺损伤组轻,血清转化生长因子-β1（TGF-β1）和肺系数、肺匀浆中经脯氨酸（HYP）的含量均好于损伤组,差异有统计学意义（P均＜0.05）.结论 MSCs注入百草枯中毒大鼠体内,通过抑制TGF-β1水平,减少纤维母细胞迁移、活化,抑制胶原蛋白产生,进而保护肺组织结构,可以更有效地抑制肺纤维化、肺实变.

Objective To explore the possible mechanism and protective effect of mesenchymal stem cell （MSC） on rats with paraquat-induced acute lung injury. Method The solution of 20% paraquat （PQ） in dose of 18 mg/kg was injected intra-peritoneally into rats to induce poisoning,and phosphate buffered solution （PBS） was given to rats instead of PQ in rats of control group. Eighty specific pathogen free （SPF） Wistar rats were randomly divided into four group： PQ plus PBS group （n = 20）, PQ plus MSCs group （n = 20）, MSCs plus PBS group （n=20）, normal group （n = 20）. The forth generation of MSCs were transfected with Ad5-EGFP virus vector, and then the MSCs-EGFP was delivered to rats through the tail vein of rats 4h after PQ. Five rats of each group were sacrificed 1 d, 3 d, 7 d and 28 days after MSCs administration, and lung tissues of rats were taken to make sections for histological observation of the migration of MSCs under fluorescence inverted microscope. The lung tissues of rats sacrificed on the 28 th day after PQ poisoning were taken for detecting pulmonary coefficient and the content of hydroxyproline （HYP） in the lung tissue homogenate, and at the same time, the levels of serum transforming growth factor-β1（TGF-β1） were assayed. Results The pathological changes of lung tissue showed that the pulmonary fibrosis and consolidation in the MSCs treatment group were milder than those in PQ poisoning model group. In the MSCs treatment group, the levels of serum TGF-β1 and lung tissue HYP, and pulmonary coefficient were lower than those of PQ poisoning model group （P〈0.05）. Conclusions The use of MSCs for treatment of paraquat intoxication can protect pulmonary structure by decrease in TGF-B1 and inhibiting the fibroblast migration, suppressing the production of collagenous protein.