Accentuated overexpression of matrix extracellular proteins in lungs of bleomycin-injured PN-1^−/−mice. Lungs from PN-1^−/− mice and their PN-1^+/+ littermates were harvested at the indicated time points after bleomycin-induced lung injury (BLM) instillation for the following analyses. Quantitative reverse transcription PCR analysis of collagen3α1 (col3α1) (A), col1α2 (B), and fibronectin (C) mRNA expressions in lung tissues. GAPDH was used as an internal control (n = 4 per group). (D) Western blot analysis of type 1 collagen (col 1) and fibronectin. GAPDH was used as a loading control. Densitometric analysis of the corresponding western blot analyses is expressed for fibronectin (E) and col 1 (F) (n = 6-10 per group). For panels A-C and E-F, data represent mean ± SEM and were analyzed by 2-tailed Mann-Whitney U test. *P < .05, **P < .01 vs respective sham.