Figure 2. Rapamycin could protect mice from bleomycin (BLM)-induced pulmonary fibrosis. Mice (n = 10 in each group) were intraperitoneally injected with vehicle (DMSO/PBS, 10%) or 5 mg/kg rapamycin every other day starting 7 days after administration of BLM (5 mg/kg). (A) Pulmonary fibrosis was determined by haematoxylin and eosin (H&E) staining. Collagen was revealed by Masson’s trichrome staining. The expression of p21 was measured by immunohistochemical analysis. (B) The protein levels of p16, p21, α-SMA and collagen I were detected by Western blot. The expression levels were quantified with ImageJ (n = 3). GAPDH was used as a loading control, *P < 0.05 and **P < 0.01. (C, D) The lung tissues were double stained with E-cadherin and p21 (C), α-SMA and collagen I (D) by immunofluorescence. The positive areas of p21 and collagen I were quantified by densitometry (n = 3), **P < 0.01.