Fig. 4: Protective effect of LSC-Exo against authentic SARS-CoV-2 infection in Syrian hamsters.

a Time courses of LSC-Exo inhalation, viral challenge, and measurements, created with Biorender.com. b Changes in body weight of hamsters over 1-week post-challenge. n = 4. c Viral RNA in oral swabs (OS) from hamsters treated with LSC-Exo, HEK-Exo or PBS. n = 5. d Viral RNA in bronchoalveolar lavage (BAL) fluid from hamsters treated with LSC-Exo, HEK-Exo or PBS at 7 days post-challenge. n = 5. e RNAscope images revealing regional distribution and viral RNA levels in hamster lungs. Immunohistochemistry analysis of SARS-N protein in lung tissues of hamsters. Scale bar, 50 μm. f Quantification analysis of positive SARS-N cell percentages in lungs of hamster. n = 15. g H&E images of representative lung sections of hamsters. n = 5 animals per group. Three images were taken for each animal. Scale bar, 500 μm. h Masson’s trichrome staining of lung sections of hamsters. n  =  5 animals per group. Three images were taken for each animal. Scale bar, 500 μm. i Ashcroft scoring analysis of lung fibrosis from challenged hamsters that performed blindly. n = 5. j Spider web plot displaying histopathological scoring of lung damage, normalized to sham control (green). Viral genomic RNA levels (k) and sgRNA levels (l) in tissues of hamsters with PBS, HEK-Exo or LSC-Exo treatment (purple, PBS; blue, HEK-Exo; and red, LSC-Exo). n = 5. Data are mean ± s.d. Statistical analysis was performed by two-way ANOVA with Tukey’s multiple comparisons (b, c, k, l) or one-way ANOVA with Bonferroni correction (d, f, i). Source data are provided as a Source Data file.