Influence of Fasting on Functional Recovery of the Isolated Heart Exposed to Ischemia Reperfusion in Young and Aged Male Albino Rats
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- Category: Vol. 80, March 2012
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Influence of Fasting on Functional Recovery of the Isolated Heart Exposed to Ischemia Reperfusion in Young and Aged Male Albino Rats,ZAINAB ABD ELWAHAB and NAHED SALAH EL-DIN MOHAMED
Abstract
Mortality due to ischemic cardiovascular diseases is significantly higher in elderly than in young adults.
In both cardiac surgical and cardiological settings, clinical interventions used to reperfuse the ischemic heart are associated with myocardial damage that is likely to influence long-term functional recovery.
The aim of this study was to investigate the effect of fasting on functional recovery of isolated heart exposed to ischemia reperfusion in young and old male rats and to study some mechanisms of protection of fasting against ischemia reperfusion.
48 male albino rats were divided according to age and diet type into young and old control rats fed on standard rat chow, ad-libitum fed group (ALG), and young and old fasted groups (FG) which included rats fasted for 3 days (3 days water only fasting). The rats were subjected to 25min of myocardial ischemia followed by 30min of reperfusion. Myocardial performance parameters were done before ischemia (baseline) and 10, 20 and 30min reperfusion.
The results showed that left ventricular developed pressure LVDP & the peak rate of maximum left ventricular pressure rise (dP/dt), as an index of contractility, increased significantly (p<0.05) (after 30min reperfusion) in young compared to old ALG and in young and old FG compared to ALG of the same age. Also cardiac expression of AMPK showed a significant increase (p<0.05) and LDH in perfusate showed a significant decrease (p<0.05) in young and old FG when compared to ALG of the same age. Histological examination of cardiac tissues showed that inflammation and degeneration were less in FG in comparison to ALG in cardiac tissues 30 minutes after reperfusion.
We concluded that senescent hearts are more susceptible to myocardial ischemia reperfusion injury than adult hearts. Slightly longer periods of fasting, prior to surgery may have protective effect against certain types of acute organ stress in young and old rats. The protective mechanism of fasting is partly mediated by increased cardiac expression of AMPK.