Figure 5

Inhibition of miR-200c-3p protects mice from H5N1 virus infection. (a) qRT-PCR analysis of miR-200c-3p expression in the lungs of mice challenged with AF or H5N1 virus for 3 days (1×10⁶ TCID₅₀ (50% tissue culture infectious dose)). (b) C57BL/6 mice (n=5, each group) were intraperitoneally injected with antagomir of miR-200c-3p or NC (10 mg kg⁻¹) 24 h before, as well as 6 and 24 h after H5N1 virus instillation (1×10⁶ TCID₅₀). Wet-to-dry lung tissue weight ratios of the mice were detected 3 days after H5N1 instillation. (c) Representative images of lung pathology (hematoxylin and eosin) of H5N1-infected mice treated with antagomir of miR-200c-3p or NC. The number of infiltrating neutrophils per microscopic field and lung injury scores are shown in the graphs. n=100 fields were analyzed for five mice for each treatment. (d) Kaplan–Meier survival curves of C57BL/6 mice intraperitoneally injected with antagomir of miR-200c-3p or NC three times (1, 24 and 48 h, 20 mg kg⁻¹) after H5N1 virus instillation (1×10⁶ TCID₅₀). **P<0.01 when comparing the antagomir-NC+H5N1 group with the antagomir-miR-200c-3p+H5N1 group (log-rank test). (e) qRT-PCR analysis of M2 and NP mRNA relative expression levels in the lungs of mice. Lung tissues were obtained on day 3 after virus instillation. (f) ACE2 protein expression in the lungs of mice was detected by western blotting. Lung tissues were obtained on day 3 after virus instillation. (g) Ang II levels in the plasma of mice were determined using radioimmunoassays. The plasma was obtained on day 3 after virus instillation. The data are shown in the graph as the mean±s.e.m. *P<0.05 and **P<0.01.