Apple pectin, a dietary fiber, ameliorates myocardial injury by inhibiting apoptosis in a rat model of ischemia/reperfusion

Abstract

BACKGROUND/OBJECTIVEMyocardial cell death due to occlusion of the coronary arteries leads to myocardial infarction, a subset of coronary heart disease (CHD). Dietary fiber is known to be associated with a reduced risk of CHD, the underlying mechanisms of which were suggested to delay the onset of occlusion by ameliorating risk factors. In this study, we tested a hypothesis that a beneficial role of dietary fiber could arise from protection of myocardial cells against ischemic injury, manifested after occlusion of the arteries.MATERIALS/METHODSThree days after rats were fed apple pectin (AP) (with 10, 40, 100, and 400 mg/kg/day), myocardial ischemic injury was induced by 30 min-ligation of the left anterior descending coronary artery, followed by 3 hr-reperfusion. The area at risk and infarct area were evaluated using Evans blue dye and 2,3,5-triphenyltetrazolium chloride (TTC) staining, respectively. DNA nicks reflecting the extent of myocardial apoptosis were assessed by TUNEL assay. Levels of cleaved caspase-3, Bcl-2, and Bax were assessed by immunohistochemistry.RESULTSSupplementation of AP (with 100 and 400 mg/kg/day) resulted in significantly attenuated infarct size (IS) (ratio of infarct area to area at risk) by 21.9 and 22.4%, respectively, in the AP-treated group, compared with that in the control group. This attenuation in IS showed correlation with improvement in biomarkers involved in the apoptotic cascades: reduction of apoptotic cells, inhibition of conversion of procaspase-3 to caspase-3, and increase of Bcl-2/Bax ratio, a determinant of cell fate.CONCLUSIONSThe findings indicate that supplementation of AP results in amelioration of myocardial infarction by inhibition of apoptosis. Thus, the current study suggests that intake of dietary fiber reduces the risk of CHD, not only by blocking steps leading to occlusion, but also by protecting against ischemic injury caused by occlusion of the arteries.

Atorvastatin alleviates experimental diabetic cardiomyopathy by suppressing apoptosis and oxidative stress

“…Paraffin sections of the LV were immunohistochemically stained for detection of cleaved caspase-3 expression as previously reported (Lim and Lee 2012;Lim et al 2014). Rabbit polyclonal anti-cleaved caspase-3 (1:50 dilution, Cell Signaling, Beverly, MA) was applied as a primary antibody.…”

Intake of hot water–extracted apple protects against myocardial injury by inhibiting apoptosis in an ischemia/reperfusion rat model

“…A diet containing WEA (designated as HWEA or CWEA) was prepared, as described previously [18]. We used a WEA-free diet (950 g), purchased from Unifaith Inc (Seoul, Korea), that consisted of casein (250 g), corn starch (482.5 g), sucrose (100 g), soybean oil (70 g), mineral mix (35 g), vitamin mix (10 g), and choline bitartrate (2.5 g; Table 1).…”

“…1). However, we recently showed that apple pectin intake attenuates myocardial injury by blocking postocclusion steps through the inhibition of apoptotic cascades in an ischemia/reperfusion rat model [18] (Fig. 1).…”

“…Intramuscularly injected butyrate attenuates myocardial injury [17], and hydrogen produced from fermentation of pectin reduces hepatic injury [16]. Intake of dietary fiber, including apple pectin, is shown to be associated with a reduced risk of coronary heart disease (CHD) [18]. In addition, apple intake is associated with a lower risk of cardiovascular disease [19,20], including acute coronary syndrome, a cardiovascular disease subgroup that Fig.…”

“…1). The reduced risk could be attributed to apple's antioxidant and cholesterol-lowering effects [18][19][20][21], which prevent the preocclusion steps leading to coronary artery occlusion (Fig. 1).…”