BackgroundWhite smoke inhalation (WSI) is an uncommon but potentially deadly cause of acute lung injury and acute respiratory distress syndrome for which no effective pharmaceutical treatment has been developed. This study aimed to determine the protective effects of human amnion-derived mesenchymal stem cells (hAMSCs) against WSI-induced lung injury in rats.MethodshAMSCs were injected into rats via the tail vein 4 h after WSI. At 1, 3, 7, 14, and 28 days after cell injection, hAMSCs labeled with PKH26 in lung, heart, liver, and kidney tissues were observed by fluorescence microscopy. The lung injury score was determined by hematoxylin and eosin staining. Lung fibrosis was assessed by Masson’s trichrome staining. The computed tomography (CT) score was assessed by CT scanning. The wet/dry weight ratio was calculated. The levels of interleukin (IL)-1β, IL-6, and IL-10 were determined by enzyme-linked immunosorbent assays. The expression of surfactant protein (SP)-A, SP-C, and SP-D was measured by Western blotting.ResultsThe injected hAMSCs were primarily distributed in the lung tissues in WSI-induced rats. Compared with the model and phosphate-buffered saline (PBS) group, hAMSC treatment led to reduced lung injury, lung fibrosis, CT score, and inflammation levels in WSI-induced mice. hAMSC treatment also resulted in increased cell retention in the lung, partial pressure of oxygen (PaO2), and PaO2/fraction of inspired oxygen (FiO2) levels, and pulmonary SP-A, SP-C, and SP-D expression compared with that in the model and PBS group.ConclusionshAMSCs are a potential cell-based therapy for WSI-induced lung injury.

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Background/Aims: White smoke inhalation (WSI) is an uncommon but potentially deadly cause of acute respiratory distress syndrome (ARDS). However, no clinical treatment protocol has been established for the treatment of WSI-induced ARDS. Therefore, it is necessary to investigate the effects of WSI in ARDS and the mechanisms underlying the effects of WSI to determine a novel therapeutic target. Methods: On the basis of the duration of continued inhalation of white smoke (3 min, 5 min, and 7 min), rats were divided into three groups (WSI-3 min, WSI-5 min, and WSI-7 min). The survival rate, pathological change, and computed tomography (CT) score were evaluated to determine the modeling conditions. In the established WSI-5 min models, evaluations were performed to evaluate the following: arterial blood gas levels, lung wet/dry weight ratio, the expression of inflammatory cytokines, and the effect of NF-κB signaling pathway. Results: The survival rate of rats at 72 h post-WSI in the WSI-3 min, WSI-5 min, and WSI-7 min groups was 83.33%, 75%, and 25%, respectively. Results from evaluation of H&E staining, CT scan, arterial blood gas levels, and lung wet/dry weight ratio suggest that the pathological changes in the rat in the WSI-5 min and WSI-7 min groups are very similar to those in patients with ARDS induced by WSI. Additionally, the expression of INF-γ, TGF-β1, TNF-α, and IL-1β were increased, and the NF-κB signaling pathway was activated in the WSI-5 min group. Conclusion: The rat model of WSI-5 min can be used as a WSI-induced ALI model for further experiments. The NF-κB signaling pathway may be a potential therapeutic target for the treatment of WSI- induced ARDS.