Comparison of bone marrow stem cells and cell-derived exosomes on oleic acid-induced lung injury in rats

Background: Acute lung injury and its complication, acute respiratory distress syndrome, are significant clinical burdens that have a limited number of therapeutic approaches. Among them, stem cells seem to be a promising alternative therapy. In this study, we investigated for the first time and compared bone marrow stem cells (BMSCs) and their exosome fractions on lung injury induced by oleic acid in rats. Methods: We administered oleic acid (60 mg/kg) by intravenous route to induce acute lung injury; thereafter, we intravenously applied rat BMSCs (1 x 10(6)) and exosome fractions (obtained from 1 x 10(6) BMSCs by a commercially available kit) to the tail vein two hours after the oleic acid administration. Twenty-four hours later, the rats were sacrificed by deep anesthesia, and we obtained lung tissues. The examination of hematoxylin and eosin-stained samples was evaluated using the parameters of bleeding, leukocyte infiltration, edema, and hyperplasia. A flow cytometer verified the exosomes obtained from the stem cell culture medium. Results: Administration of stem cells and exosome fractions after lung injury restored all those parameters; however, the regenerative capacity of BMSCs was better than its exosome fraction (p =0.004). Conclusion: Stem cells and their exosome fractions can be regarded as therapeutic alternatives in treating oleic acid- induced lung injury in rats, being rather than exosomes their maternal source; the stem cells seem more potent.