Fig. 3.

Ascorbate prevents tobacco smoke-induced elastin breakdown, MMP-9 overexpression, and consequent emphysematous lung damage. (A) Representative histology from hematoxylin-stained lung sections of CS-exposed, CS+Asc (ascorbate), CS+L-NIL, CS+Asc+L-NIL and sham control guinea pigs (10 fields, n = 6). CS-induced alveolar damage is morphometrically represented in terms of Lm (B) and Di (C). (D) Immunoblots show levels of elastin breakdown, MMP-9 overexpression, and Bax and Bcl-2 expression levels in the whole-lung lysates due to CS exposure under the indicated treatment conditions along with corresponding ratios of Bax and Bcl-2 expression levels (E). (F) Lung sections immunostained with anti-elastin primary antibody and secondary antibody conjugated with Alexa Fluor 568 (green) (10 fields, n = 6). (G) Indicated lung sections subjected to TUNEL analysis against nuclear staining with DAPI (blue) (10 fields, n = 6). Activity levels of iNOS in the heart (H) and liver (I) tissues of CS-treated animals subjected to lung-specific L-NIL treatment (n = 6). Data were statistically analyzed by paired Student’s t test. Significant differences (*P < 0.05) were found between groups as indicated. Data are represented as means ± SD and are representative of three independent experiments done under similar conditions. (Scale bars: 100 µm.)