Abstracts

Secondhand Smoke (SHS) exposure is associated with an increased risk of coronary artery disease. This study’s aim was to investigate the relationship of SHS exposure in old rats’ left ventricle impaired and fibrosis. To explore the mechanism of cardiac remodeling of exposure to SHS exposure whether it was exacerbated cardiac impaired, especially in the older left ventricle. The animals were placed in a transparent exposure chamber, connected to smoking device and exposed to 15 cigarettes, smoke for 30 min, twice a day, 6 days/week, for 1 month. Histopathologic of left ventricular sections were stained with hematoxylin-eosin staining (H&E) and Masson’s trichrome. Left Ventricular (LV) morphological variables assessed using H&E stained and Mass weight changes. The cardiac structures were measured by echocardiographic analysis.

LV remodeling and fibrosis-related proteins were detected by gelatin zymography and western blotting analysis. Inflammatory and hypertrophy related proteins were also detected. Results showed in old rats’ group and old rats in the secondhand smoke exposure group (Old SHS Exp) were observed LV wall and mass increased, collagen accumulation and fibrosis, and extracellular space increased. From echocardiographic results, we found LV functions were apparently decreased, LV interventricular septum at systolic and diastolic diameters increased in the Old SHS Exp group. Cardiomyocyte width was increased in old rats, but the length was increased in Old SHS Exp group. Reduced MMP 2 proteins expression and TIMPs increased were induced fibrosis in the Old SHS Exp group. JNK1, p38, IL-6, TNFα were increased by western blotting and immunohistochemistry antibody-positive expression was observed in the Old SHS Exp group.

Abbreviations: Secondhand smoke exposure; Left ventricle; Cardiac impaired; Left ventricular hypertrophy; Echocardiographic; Cardiomyocyte