Intravenous Injection of Human Umbilical Cord Mesenchymal Stem Cells Can Alleviate Acute Lung Injury in Rats.

This study aimed to investigate the therapeutic effect and potential mechanism of intravenous injection of human umbilical cord mesenchymal stem cells (hUCMSCs) on acute lung injury (ALI) in rats. Wistar albino rats were used to establish an ALI animal model via intravenous oleic acid suspension injection. Rats in the low-dose and high-dose mesenchymal stem cell (MSC) groups were treated with 2.5×10^5 hUCMSCs and 5×10^5 hUCMSCs, respectively. After 24 hours of modelling, the rats were sacrificed and samples were collected. The lung coefficient was calculated, and lung tissue morphology was examined. The expression levels of TNF-α, IL-1β, IL-4, IL-6, and IL-10 in lung tissue and serum were assessed. Additionally, the expression of Claudin-5, Occludin, and ZO-1 in the lung was measured. Compared with the control group, lung volume and lung coefficient significantly increased, and lung tissue exhibited pathological changes with an increased lung injury score. Levels of TNF-α, IL-1β, and IL-6 in lung tissue and serum significantly increased, while IL-4 and IL10 levels significantly decreased. The proportion of neutrophils markedly increased, and the expression of Claudin-5, Occludin, and ZO-1 in the lung significantly decreased in the model group. These results indicate that oleic acid can induce acute lung injury and activate inflammatory. Compared with the model group, both MSC-treated groups showed significant reductions in lung coefficient and lung injury score. Levels of TNF-α, IL-1β, and IL-6 in lung tissue and serum significantly decreased, while IL-4 and IL-10 levels significantly increased. Furthermore, the proportion of neutrophils decreased significantly, and the expression of Claudin-5, Occludin, and ZO-1 in the lung increased significantly in the two MSC-treated groups. The therapeutic effect can likely be ascribed to the immunomodulatory properties of hUCMSCs and capacity to mitigate barrier damage, as substantiated by the decreased levels of pro-inflammatory cytokines, along with the elevated expression of antiinflammatory factors and tight junction proteins in lung tissue. The hUCMSCs can effectively ameliorate oleic acid-induced ALI in rats by exerting anti-inflammatory effects and protecting the alveolar-capillary endothelial barrier.