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

BACKGROUND: 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. METHODS: 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. RESULTS AND DISCUSSION: 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. CONCLUSION: The hUCMSCs can effectively ameliorate oleic acid-induced ALI in rats by exerting anti-inflammatory effects and protecting the alveolar-capillary endothelial barrier.