Wang Hong-yang, Liu Chen, Wang Yan, Zhang Li-li, Liu Xin-rong, Liu He-liang
Pulmonary department of Hebei United University hospital, Tangshan, Hebei Province 063000, China (E-mail:
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2013 Sep;31(9):675-80.
To investigate the therapeutic effect and possible action mechanism of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) in the treatment of bleomycin-induced pulmonary fibrosis in rats.
The second generation of hUCB-MSCs was cultured to the fourth generation. Sixty healthy male Sprague-Dawley rats (clean grade) were randomly and equally divided into 4 groups: bleomycin group, stem cell treatment group, dexamethasone treatment group, and negative control group. A pulmonary fibrosis model was established by intratracheal instillation of bleomycin in the bleomycin group, stem cell treatment group, and dexamethasone treatment group. The stem cell treatment group was injected with stem cells labeled with 5-bromo-2-deoxyuridine (Brdu) via the caudal vein immediately after the model was established. The dexamethasone treatment group was intraperitoneally injected with dexamethasone for 7 d from the next day after the model was established. The negative control group was given an equal volume of normal saline by intra-tracheal instillation. In each group, 5 rats were sacrificed in the 7th, 14th, and 28th days. The expression of transforming growth factor β1 (TGF-β1) and Brdu-labeled stem cells were observed by HE and Masson staining and immunohistochemistry. Lung hydroxyproline content was determined by acid hydrolysis.
The stem cell treatment groups had Brdu-labeled stem cells seen in lung tissue in the 7th, 14th, and 28th days. Compared with the negative control group, the bleomycin group, stem cell treatment group, and dexamethasone treatment group had significantly increased scores of alveolitis and pulmonary fibrosis (P < 0.05). In the 7th, 14th, and 28th days, the scores of alveolitis in stem cell treatment group and dexamethasone treatment group were significantly lower than those in bleomycin group (P < 0.05); in the 28th day, the scores of pulmonary fibrosis in stem cell treatment group and dexamethasone treatment group were significantly lower than that in bleomycin group (P < 0.05). There were no significant differences in scores of alveolitis and pulmonary fibrosis between the dexamethasone treatment group and stem cell treatment group (P > 0.05). Compared with the bleomycin group, the stem cell treatment group and dexamethasone treatment group had significantly decreased number of TGF-β1-positive cells and hydroxyproline content in lung tissue at all time points (P < 0.05). There were no significant differences in number of TGF-β1-positive cells and hydroxyproline content in lung tissue between the stem cell treatment group and dexamethasone treatment group (P > 0.05).
hUCB-MSCs can be transplanted into damaged lung tissue and effectively reduce alveolitis and pulmonary fibrosis in the early stage of pulmonary fibrosis. The action mechanism of hUCB-MSCs may involve inhibiting the expression of TGF-β1 and reducing the formation of collagen.
探讨人脐带血间充质干细胞（hUCB-MSCs）对博莱霉素诱导的大鼠肺纤维化的治疗作用及可能的作用机制。
将第二代hUCB-MSCs培养至第四代。将60只健康雄性Sprague-Dawley大鼠（清洁级）随机等分为4组：博莱霉素组、干细胞治疗组、地塞米松治疗组和阴性对照组。博莱霉素组、干细胞治疗组和地塞米松治疗组通过气管内滴注博莱霉素建立肺纤维化模型。干细胞治疗组在模型建立后立即经尾静脉注射用5-溴-2-脱氧尿苷（Brdu）标记的干细胞。地塞米松治疗组在模型建立后的次日起连续7天腹腔注射地塞米松。阴性对照组经气管内滴注等体积的生理盐水。每组在第7、14和28天处死5只大鼠。通过HE和Masson染色及免疫组化观察转化生长因子β1（TGF-β1）的表达和Brdu标记的干细胞。采用酸水解法测定肺组织羟脯氨酸含量。
干细胞治疗组在第7、14和28天肺组织中可见Brdu标记的干细胞。与阴性对照组相比，博莱霉素组、干细胞治疗组和地塞米松治疗组的肺泡炎和肺纤维化评分显著升高（P < 0.05）。在第7、14和28天，干细胞治疗组和地塞米松治疗组的肺泡炎评分显著低于博莱霉素组（P < 0.05）；在第28天，干细胞治疗组和地塞米松治疗组的肺纤维化评分显著低于博莱霉素组（P < 0.05）。地塞米松治疗组和干细胞治疗组之间的肺泡炎和肺纤维化评分无显著差异（P > 0.05）。与博莱霉素组相比，干细胞治疗组和地塞米松治疗组在所有时间点肺组织中TGF-β1阳性细胞数量和羟脯氨酸含量均显著降低（P < 0.05）。干细胞治疗组和地塞米松治疗组之间肺组织中TGF-β1阳性细胞数量和羟脯氨酸含量无显著差异（P > 0.05）。
hUCB-MSCs可移植到受损肺组织中，并有效减轻肺纤维化早期的肺泡炎和肺纤维化。hUCB-MSCs的作用机制可能涉及抑制TGF-β1的表达并减少胶原蛋白的形成。
