Cardioprotective effect of naringin against the ischemia/reperfusion injury of aged rats

Aging is known as a main risk factor in the development of cardiovascular diseases. Naringin (NRG) is a flavonoid compound derived from citrus fruits. It possesses a wide spectrum of pharmacological properties, including antioxidant anti-inflammatory, and cardioprotective. This investigation aimed to assess the cardioprotective effect of NRG against the ischemia/reperfusion (I/R) injury in aged rats. In this study, D-galactose (D-GAL) at the dose of 150 mg/kg/day for 8 weeks was used to induce aging in rats. Rats were orally gavaged with NRG (40 or 100 mg/kg/day), in co-treatment with D-GAL, for 8 weeks. The Langendorff isolated heart was used to evaluate the effect of NRG on I/R injury in aged rats. NRG treatment diminished myocardial hypertrophy and maximum contracture level in aged animals. During the pre-ischemic phase, reduced heart rate was normalized by NRG. The effects of D-GAL on the left ventricular end diastolic pressure (LVDP), the rate pressure product (RPP), and the minimum and maximum rate of left ventricular pressure (±dp/dt) improved by NRG treatment in the perfusion period. NRG also enhanced post-ischemic recovery of cardiac functional parameters (± dp/dt, and RPP) in isolated hearts. An increase in serum levels of the lactate dehydrogenase (LDH), the creatine kinase-MB (CK-MB), and the tumor necrosis factor-alpha (TNF-α) were reversed by NRG in aged rats. It also normalized the D-GAL-decreased the superoxide dismutase (SOD) activity in the heart tissue. NRG treatment alleviated cardiac injury in aged hearts under conditions of I/R. NRG may improve aging-induced cardiac dysfunction through anti-oxidative and anti-inflammatory mechanisms.