The Effect of Intermittent Fasting on Isoproterenol-Induced Myocardial Infarction in Aged Rats: A Potential Role of Autophagy
Sahar M El Agaty, Noha A Nassef, Doaa A Abou-bakr, Aya A Hanafy- General Medicine
Background
Aging is associated with cardiovascular and metabolic changes, increasing the susceptibility to acute myocardial infarction (MI). Intermittent fasting (IF) was found to reduce the age associated cardiovascular diseases.
Aim
To investigate the possible protective effect of IF against acute MI induced by isoproterenol (ISO) in old rats and its underlying mechanisms, including autophagy.
Methods
50 male Wistar rats were equally divided into five groups: Adult; Old; Old-F (rats were subjected to IF for 4 weeks); Old-ISO (rats subjected to MI by ISO) and Old-F-ISO groups.
Results
IF significantly reduced troponin-I and creatine kinase (CK-MB), cardiac malondialdehyde (MDA) and TNF- α in Old-F-ISO compared to Old-ISO group. This was associated with a significant decrease in the age-related overall and visceral obesity; and dyslipidemia in Old-F and Old-F-ISO versus Old and Old-ISO groups. IF increases cardiac Atg-5 in Old-F-ISO versus Old group. Also, IF attenuated the age-related diabetic changes and significantly increased the pancreatic Atg-7 in Old-F-ISO versus Old group. Histological studies revealed attenuation of the local inflammatory response in Old-F-ISO versus Old-ISO group. Pancreatic Atg-7 and heart Atg-5 were significantly increased in Old-ISO versus Old rats.
Conclusion
IF protects against acute MI in old rats, in part, via alleviation of the age-related obesity, diabetic changes, and dyslipidemia. Chronic activation of heart and pancreatic autophagy by IF may possibly afford a cardioprotective effect. Acute activation of both heart and pancreatic autophagy by ISO could have a deleterious effect, augmenting cardiac injury.