Figure 6

SHS exposure increases MMP-9 expression and RAGE KO mice lessen the degree of SHS-mediated MMP-9 augmentation. Lungs from wild type room air exposed (A), SHS-exposed wild type (B), and SHS-exposed RAGE KO mice (C) were qualitatively immunostained for MMP-9. SHS induced a detectibly higher number of MMP-9 positive cells (B, arrows) compared to SHS-exposed RAGE KO mice (C). Immunoblotting for MMP-9 (D) and related densitometry (E) using standardized aliquots of 10 μg total lung protein revealed markedly increased MMP-9 expression levels in SHS-exposed wild type animals and notable protection in SHS-exposed RAGE KO animals. Gelatin zymography revealed increased synthesis of MMP-9 by SHS-exposed wild type animals compared to all other groups and active MMP-9 was also significantly elevated in SHS-exposed wild type animals compared to SHS-exposed RAGE KO mice (F). Immunoblotting data are representative of experiments performed in triplicate. Images were at 100X original magnification and scale bars equal 100 nm.