Figure 5

Effect of N-acetyl cysteine (NAC) on CS-induced protein oxidation in vitro and apoptosis and lung damage in guinea pigs in vivo . A, CS-induced protein carbonyl formation in BSA in the presence and absence of NAC and vitamin C, as measured by immunoblot analysis. The incubation mixture contained BSA (1 mg) AECS (50 μl), NAC (100 μM) or vitamin C (200 μM) in a final volume of 200 μl of 50 mM potassium phosphate buffer, pH 7.4; incubated for 2 h at 37°C with shaking. After incubation, production of the DNP derivative was measured by immunoblot analysis, as describe before [6]. B, Detection of DNA strand breaks in lung cells of guinea pigs exposed to air or CS in the presence of NAC by TUNEL assay. After feeding vitamin C-free diet for 7 days, the guinea pigs were supplemented with 1 mg vitamin C/day and fed 15 mg NAC/animal/day and exposed to air or CS for 7 days, as described under Methods. C, Quantitative evaluation of TUNEL positive cells in lungs of guinea pigs exposed to CS in the presence or absence of NAC. Eight images were analyzed in 4 lung sections (2 images/section/animal) from each group, respectively; bars over the respective columns represent means ± SD. D, Histopathology profiles of lung sections of guinea pig after exposure to CS in the presence and absence of NAC (15 mg/animal/day). The number of guinea pigs used in each group was 4. Eight images were analyzed in 4 lung sections (2 images/section/animal) from each group (magnification ×10). E, F, Morphometric Measurements of alveolar air space, and surface density (S/V). Values are ± SD; number of images analyzed in each group:8.