No abstract

The mesenchymal stem cell (MSC) is a potential strategy in the pretreatment of traumatic acute lung injury (ALI), a disease that causes inflammation and oxidative stress. This study aimed to investigate whether MSC-exosomal microRNA-124-3p (miR-124-3p) affects traumatic ALI. Initially, a traumatic ALI rat model was established using the weight-drop method. Then, exosomes were obtained from MSCs of Sprague-Dawley rats, which were injected into the traumatic ALI rats. We found that miR-124-3p was abundantly-expressed in MSCs-derived exosomes and could directly target purinergic receptor P2X ligand-gated ion channel 7 (P2X7), which was overexpressed in traumatic ALI rats. After that, a loss- and gain-of-function study was performed in MSCs and traumatic ALI rats to investigate the role of miR-124-3p and P2X7 in traumatic ALI. MSC-derived exosomal miR-124-3p or silenced P2X7 was observed to increase the survival rate of traumatic ALI rats and enhance the glutathione/superoxide dismutase activity in their lung tissues. However, the wet/dry weight of lung tissues, activity of methylenedioxyamphetamine and H2O2, and levels of inflammatory factors (TNF-a, IL-6, and IL-8) were reduced. Similarly, the numbers of total cells, macrophages, neutrophils, and lymphocytes in bronchoalveolar lavage fluid were also reduced when treated with exosomal miR-124-3p or silenced P2X7. In conclusion, the results provide evidence that miR-124-3p transferred by MSC-derived exosomes inhibited P2X7 expression, thus improving oxidative stress injury and suppressing inflammatory response in traumatic ALI, highlighting a potential pretreatment for traumatic ALI.

Rationale:Negative pressure pulmonary edema (NPPE) is a dangerous clinical complication and potentially life-threatening emergency without prompt diagnosis and intervention during recovery period after anesthetic extubation.Patient concerns:A 25-year-old woman has undergone endoscopic thyroidectomy. After extubation, the patient developed acute respiratory distress with high airway resistance accompanied with wheezing, oxyhemoglobin saturation (SpO2) decreased to 70%. With positive pressure mask ventilation, her condition was stable, SpO2 99%. However, the patient developed pink frothy sputum with diffuse bilateral rales 30 min later after transported to surgical intensive care unit (SICU).Diagnoses:Negative pressure pulmonary edema.Interventions:The patient was undergone assisted ventilation with continuous positive airway pressure (CPAP) and furosemide 20 mg was given intravenously.Outcomes:Postoperative day (POD) 2 her condition became stable, computed tomography (CT) scan indicated the pulmonary edema disappeared. The patient was discharged 6 days later. No abnormalities were observed during following 4 weeks.Lessons:Although usually the onset of NPPE is rapid, with individual differences NPPE is still challenging. Increased vigilance in monitoring, diagnosis, and treatment are essential to prevent aggravation and further complication.