目的:通过气管内给药的方法比较不同浓度人脐带间充质干细胞气管内移植对重度烧伤致急性肺损伤大鼠的保护作用。方法:建立50%面积全层烫伤大鼠模型,将75只成熟雄性Wistar大鼠随机分为正常对照组(A组)、生理盐水组(B组)、1×10~5HUCMSCs移植组(C)、5×10~5HUCMSCs移植组(D)、1×10~6HUCMSCs移植组(E),每组15只,B组及移植组(C、D、E组)烫伤后立即液体复苏,B组烫伤后气管内滴注0.2 m L生理盐水,移植组气管内滴注不同浓度h UCMSCs,分别在移植后的天第1、3、7天留取大鼠肺组织标本,HE染色观察肺组织病理变化,MPO、CD68免疫组化染色观察肺组织中性粒细胞及肺巨噬细胞阳性表达情况。结果:肺组织病理切片可见:A组各时间点肺泡腔清晰,肺泡结构完整,偶见少量炎性细胞。烫伤后第1天,B组及移植组(C、D、E组)肺泡间隔增厚,大量红细胞漏出及炎性细胞浸润。烫伤后第3天,各组肺泡结构较前清晰,炎性细胞浸润及红细胞漏出较第一天减少,与B组相比移植组肺泡结构清晰,间隔变薄,移植组各组间改变不明显。烫伤后第7天,移植组肺组织损伤较B组明显减轻,E组损伤肺组织恢复最为明显。MPO染色显示:与A组相比,阳性细胞数在烫伤后第1天明显增加(P<0.05),但各组之间无明显差异。在烫伤后第3天,与B组相比,移植组阳性细胞数减少明显(P<0.05),E组阳性细胞减少明显(P<0.05);在烫伤后第7天E组阳性细胞数量较其他组显著减少(P<0.05)。CD68染色显示在烫伤后第1天各组阳性细胞显著增多(P>0.05),在烫伤后第3天移植组阳性细胞数减少(P<0.05),但各移植组间无明显差异,烫伤后第7天移植组阳性细胞数量较B组明显减少(P<0.05),E组较C、D组阳性细胞减少有显著差异(P<0.05)。结论:气管内移植HUCMSCs能修复重度烧伤后损伤的肺组织,减少肺组织中性粒细胞及巨噬细胞的浸润,且1×10~6HUCMSCs移植效果更明显。 OBJECTIVE: To compare the protective effects of different concentrations of human umbilical cord mesenchymal stem cells tracheal transplantation on acute burn injury induced by severe burns in rats by intratracheal administration. Methods: A total of 75 mature male Wistar rats were randomly divided into normal control group (group A), normal saline group (group B), 1 × 10 ~ 5HUCMSCs transplantation group (group C) , 5 × 10 ~ 5HUCMSCs transplantation group (D), 1 × 10 ~ 6HUCMSCs transplantation group (E), 15 rats in each group, B group and transplantation group (C, D and E group) 0.2 ml saline was injected into the trachea, and different concentrations of hUCMSCs were instilled intratracheally in the transplanted group. The lung tissue samples were collected on the 1st, 3rd, 7th day after transplantation. The pathological changes of the lung tissue were observed by HE staining , MPO, CD68 immunohistochemical staining lung tissue neutrophil and lung macrophages positive expression. Results: The pathological sections of lung tissue showed that the alveolar space was clear and the alveolar structure was intact at the same time in group A, and a few inflammatory cells were occasionally seen. On the first day after scald, the alveolar septum thickens, a large number of erythrocyte leakage and infiltration of inflammatory cells in group B and transplantation group (C, D and E). On the 3rd day after scald, the alveolar structure in each group was clear, the infiltration of inflammatory cells and the leakage of erythrocytes were decreased compared with those on the first day. Compared with group B, the alveolar structure in the transplantation group was clear and the interval was thin. . On the 7th day after scald, the damage of lung tissue in the transplantation group was significantly lessened than that of the B group, and the recovery of the lung tissue in the E group was the most obvious. MPO staining showed that compared with group A, the number of positive cells increased significantly on the first day after scald (P <0.05), but there was no significant difference between groups. Compared with group B, the number of positive cells in transplantation group decreased significantly (P <0.05), and the number of positive cells in group E decreased significantly (P <0.05). On the 7th day after scalding, the number of positive cells in group E was significantly higher than that in group B Other groups were significantly reduced (P <0.05). CD68 staining showed that the number of positive cells in each group increased significantly (P> 0.05) on the first day after scald, and the number of positive cells in the transplantation group decreased on the third day after scald (P <0.05), but there was no significant difference between the groups after scald On the 7th day, the number of positive cells in the transplantation group was significantly lower than that in the B group (P <0.05). There was a significant difference between the E group and the C and D groups (P <0.05). CONCLUSION: Transplantation of HUCMSCs into trachea can repair the lung tissue after severe burn injury and reduce the infiltration of neutrophils and macrophages in the lung tissue. The transplantation of 1 × 10 ~ 6HUCMSCs is more effective.