20 February 2018
Int J Med Sci 2015; 12(9):708-718. doi:10.7150/ijms.12032
Secondhand Smoke Exposure Reduced the Compensatory Effects of IGF-I Growth Signaling in the Aging Rat Hearts
1. Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
Background: Secondhand smoke (SHS) exposure is associated with increased risk of cardiovascular disease. Aging is a physiological process that involves progressive impairment of normal heart functions due to increased vulnerability to damage. This study examines secondhand smoke exposure in aging rats to determine the age-related death-survival balance.
Methods: Rats were placed into a SHS exposure chamber and exposed to smog. Old age male Sprague-Dawley rats were exposed to 10 cigarettes for 30 min, day and night, continuing for one week. After 4 weeks the rats underwent morphological and functional studies. Left ventricular sections were stained with hematoxylin-eosin for histopathological examination. TUNEL detected apoptosis cells and protein expression related death and survival pathway were analyzed using western blot.
Results: Death receptor-dependent apoptosis upregulation pathways and the mitochondria apoptosis proteins were apparent in young SHS exposure and old age rats. These biological markers were enhanced in aging SHS-exposed rats. The survival pathway was found to exhibit compensation only in young SHS-exposed rats, but not in the aging rats. Further decrease in the activity of this pathway was observed in aging SHS-exposed rats. TUNEL apoptotic positive cells were increased in young SHS-exposed rats, and in aging rats with or without SHS-exposure.
Conclusions: Aging reduces IGF-I compensated signaling with accelerated cardiac apoptotic effects from second-hand smoke.
Keywords: Secondhand smoke exposure, aging, age-related death-survival balance, cell cycle, apoptosis.
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How to cite this article:
Wu JP, Hsieh DJY, Kuo WW, Han CK, Pai P, Yeh YL, Lin CC, Padma VV, Day CH, Huang CY. Secondhand Smoke Exposure Reduced the Compensatory Effects of IGF-I Growth Signaling in the Aging Rat Hearts. Int J Med Sci 2015; 12(9):708-718. doi:10.7150/ijms.12032. Available from http://www.medsci.org/v12p0708.htm