Dietary polyphenol quercetin protects rat hearts during reperfusion: enhanced antioxidant capacity with chronic treatment.

OBJECTIVE

Quercetin is an important member of dietary flavonoid family and widely present in red wine and Mediterranean diet. The major objective of the this study is to evaluate the beneficial effects of quercetin in protecting the myocardium from the deleterious effects of ischemia reperfusion (I/R) injury in chronic quercetin treatment with or without an acute quercetin infusion protocols.

METHODS

Forty male Sprague-Dawley rats were included in this experimental randomized study/ Langendorff perfused isolated rat hearts were subjected to 60-min of global ischemia period following 60-min of reperfusion. All animals were randomly divided into 4 groups. Group 1 animals were kept as controls. Group 3 and 4 animals received 50 mg/kg quercetin via an intragastric tube for 7 days for chronic treatment. Group 2 and 4 animals received an acute 15 mmol/L infusion for 30 minutes before the onset of ischemia. The myocardial postischemic recovery was compared using hemodynamic data (peak systolic pressure, end-diastolic pressure and +dP/dtmax), coronary flow, biochemical parameters (lactate dehydrogenase, creatine kinase-MB fraction, cardiac troponin I) from coronary effluent, and oxidative stress markers (malondialdehyde, glutathione, glutathione reductase and nitrite) from heart tissue homogenates in each group.

RESULTS

Quercetin has provided increased preservation in myocardial recovery in both chronic and acute treatment protocols compared to non-treated group. According to all estimated hemodynamic parameters, while the statistical difference between acute treated hearts and control hearts was significant (p<0.05); this significance was more clear in chronic treated groups (group 3 and 4) when compared to control (p<0.01). Likewise, biochemical and oxidative stress markers displayed significant differences in acute treated and chronic treated hearts when compared to control (p<0.05 and p<0.01, respectively).

CONCLUSION

As a major dietary flavonoid, due to its antioxidant and cytoprotective actions, quercetin has the capacity to protect the myocardial tissue against global ischemia and reperfusion injury. In instances where the molecule is administered for the purpose of acute therapy, this cardioprotective effect of a significant degree can be observed to; however, this potency is further accentuated upon administration as a chronic treatment protocol for seven days.