Fig. 5

EV-let-7a-5p ameliorates inflammation and improve ALI rat condition. A Lung weight-to-body weight ratio assessment. B Arterial oxygen saturation (SaO₂) of the carotid artery was measured by Waters Medical Systems Oxicom 3000A. The plasma levels of IL-4 (C) and IL-10 (D) were detected by ELISA. E, F CD68⁺ and F4/80⁺ cells in the lung parenchyma were detected by immunofluorescence. Representative images show monocytes/macrophages (F4/80⁺, green; CD68⁺, green). Nuclei were counterstained with DAPI (blue). Scale bar = 100 μm. G Collagen deposition (blue) in the lung parenchyma was detected by Masson trichrome staining. Scale bar = 100 μm. H The protein expressions of IL-10 and TGF-β were detected by Western blot. β-actin as the internal. Statistical analyses were performed using a Student’s t-test. Sham: healthy rat (n = 6 rats). Veh: ALI treated with PBS (n = 7 rats). EV-CNP: ALI treated with EV-CNP (n = 3 rats). EV-let-7a-5p: ALI treated with let-7a-5p enriched EVs (n = 6 rats). Data were presented as mean ± standard deviation. The data were analyzed by two-tailed unpaired Student’s t-test. (*p < 0.05, **p < 0.01, ***p < 0.001, ns = non-significant)