Fig. 1: SiNPs induce pulmonary fibrosis (PF).

a SiNPs were imaged by TEM. SiNPs size showed approximately normal distribution, and the average SiNPs size was about 26.85 nm. Scale bar: 50 nm. b XRD analysis of SiNPs using CuKα (λ = 1.54 Å) as a radiation source. c–i The mice were instilled once with SiNPs and sacrificed 1 month later. c Lung compliance was determined by Buxco system. d The weights of lung and body were recorded to determine the lung/body coefficient. e, f The lung tissue sections were stained by Masson staining (e) or Sirius red staining (f) to identify collagen fibers. g The hydroxyproline (HYP) content in lung tissue was assessed by spectrophotometry. h The relative CTGF mRNA level was measured by qRT-PCR. i The expression level of α-SMA was detected by immunohistochemistry (IHC). Data are presented as mean ± SEM (n = 5 for each group). *P < 0.05, **P < 0.01. Scale bars: 100 μm