Phosgene-induced lung injury is an important type of acute lung injury (ALI). Currently, no effective clinical treatment has been developed yet. Our previous study revealed that expressions of 6 miRNAs were significantly increased in phosgene-induced lung injury. The screened miRNA with the most significant effect on hepatocyte growth factor (HGF) expression by mesenchymal stem cells (MSCs) was transfected into MSCs. This study aimed to investigate whether the transfected MSCs had better therapeutic effects than MSCs alone. MSCs were co-cultured with miRNA mimics for 24h and 48h. HGF expression in culture supernatant was detected by ELISA. HGF expression in MSCs was detected by Western blot after being co-cultured with the selected miRNA inhibitor. The transfected MSCs were given to rats suffering from phosgene-induced lung injury. Expressions of TNF-α, IL-6, IL-1β and IL-10, were assayed by ELISA. SP-C mRNA level was tested by RT-PCR. VE-CAD expression was tested by Western blot. We found that miRNA-378a-5p most increased HGF expression among the six miRNAs. After transfection of MSCs with miRNA-378a-5p inhibitor, HGF expression was decreased. Compared with untreated MSCs, MSCs transfected with miRNA-378a-5p exhibited more significant decreases in lung injury score, white blood cell count and protein content while restoring respiratory indexes. Meanwhile, expressions of TNF-α, IL-6, IL-1β were decreased while those of IL-10, SP-C and VE-cadherin were increased. In conclusion, MSCs transfected with miRNA-378a-5p were more effective in treating phosgene-induced lung injury by repairing the secretion of alveolar epithelial cells and improving the permeability of vascular endothelial cells compared with MSCs alone.

光气诱导的肺损伤是急性肺损伤（ALI）的一种重要类型。目前，尚未开发出有效的临床治疗方法。我们以前的研究表明，在光气诱导的肺损伤中6种miRNA的表达显着增加。将间充质干细胞（MSCs）对肝细胞生长因子（HGF）表达影响最大的miRNA转染到MSCs中。这项研究旨在调查转染的MSC是否比单独的MSC具有更好的治疗效果。将MSC与miRNA模拟物共培养24小时和48小时。通过ELISA检测培养上清液中的HGF表达。与选定的miRNA抑制剂共培养后，通过Western blot检测MSC中的HGF表达。将转染的MSCs给予遭受光气诱导的肺损伤的大鼠。ELISA法检测TNF-α，IL-6，IL-1β和IL-10的表达。通过RT-PCR测试SP-C mRNA水平。通过蛋白质印迹测试VE-CAD表达。我们发现，miRNA-378a-5p在六个miRNA中最多增加了HGF的表达。用miRNA-378a-5p抑制剂转染MSC后，HGF表达降低。与未处理的MSC相比，转染miRNA-378a-5p的MSC在恢复呼吸指数的同时，肺损伤评分，白细胞计数和蛋白质含量的降低更为明显。同时，TNF-α，IL-6，IL-1β的表达降低，而IL-10，SP-C和VE-钙黏着蛋白的表达升高。结论，