Cardiovascular pharmacology Diosmin pretreatment improves cardiac function and suppresses oxidative stress in rat heart after ischemia/reperfusion Oomaidurai Senthamizhselvan, Jeganathan Manivannan, Thangarasu Silambarasan, Boobalan Raja n Q1 Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India article info Article history: Received 30 January 2014 Received in revised form 10 April 2014 Accepted 16 April 2014 Keywords: Diosmin Langendorff TCA cycle Rate pressure product Antioxidant abstract Reperfusion of ischemic tissue leads to the generation of oxygen derived free radicals which plays an important role in cellular damage. Objective of the current study is to evaluate the cardio-protective and antioxidant effect of diosmin on ischemia–reperfusion related cardiac dysfunction, oxidative stress and apoptosis. Diosmin (50 and 100 mg/kg body weight (bw)) was given every day to the rats orally throughout the experimental period. Ischemia/reperfusion protocol was carried out ex vivo using langendorff perfusion method and the cardiac functional recovery was assessed in terms of percentage rate pressure product. Coronary effluents of LDH and CK-MB activities, antioxidant enzyme activities, lipid peroxidation products, activity of TCA cycle enzymes were evaluated. Moreover, in vitro superoxide anion and hydroxyl radical scavenging potential of diosmin was also quantified. Finally, quantitative real- time PCR was used for assessing Bcl-2 mRNA expression in heart. Cardiac functional recovery was impaired after reperfusion compared with continuously perfused heart. It was significantly prevented by diosmin treatment. Impaired antioxidant enzyme activities and elevated lipid peroxidation products level were also significantly suppressed. The activity of TCA cycle enzymes was protected against reperfusion stress. Down regulated Bcl-2 was also significantly increased. This study concluded that diosmin pretreatment prevents all the impaired patterns including cardiac function, oxidative stress and apoptosis associated with reperfusion in control heart by its antioxidant role. & 2014 Published by Elsevier B.V. 1. Introduction Myocardial ischemic injury results from severe impairment of coronary blood supply and produces a spectrum of clinical syndromes. It is well known that ischemia/reperfusion (I/R) leads to functional, metabolic and structural abnormalities in the myo- cardium and there is a great deal of evidence showing that both cytosolic Ca 2 þ overload and oxidative stress are pivotal factors underlying ischemia/reperfusion injury in the heart (Buja, 2005; Dhalla et al., 2007; Moens et al., 2005; Powers et al., 2007). Myocardial ischemia–reperfusion injury contributes to adverse cardiovascular outcomes after myocardial ischemia, cardiac sur- gery or circulatory arrest. Primarily, no blood flow to the heart causes an imbalance between oxygen demand and supply, result- ing in damage or dysfunction of the cardiac tissue. Restoration of blood flow and reoxygenation to the ischemic myocardium, named reperfusion frequently associated with an exacerbation of tissue injury (Frank et al., 2012). As a result of intensive investigation over decades, a detailed understanding is now available about the complexity of response of the myocardium to an ischemic insult. Ischemia/reperfusion (I/R) injury results in cell death of cardiac myocytes and consequently reduced myocardial function. Endogenous reactive oxygen species appear to play important roles in modulating normal cellular processes and the intracellular antioxidant system can balance the effect of reactive oxygen species under normal conditions, under abnormal condition, the antioxidant mechanism is undermined and reactive oxygen species-induced tissue damage can take place (Law et al., 2013). Mitochondrial dys- function during cardiac ischemia/reperfusion injury is associated with Ca 2 þ overload, excess emission of reactive oxygen species and reactive nitrogen species that can lead to deleterious post- translational modifications of mitochondrial proteins. Superoxide (O 2  ), the origin of most O 2 -derived free radicals, is overproduced and under scavenged during cardiac I/R injury (Yang et al., 2012). Since oxidative stress is a key factor that contributes to ischemia– reperfusion injury, antioxidant treatment is considered as a potential strategy to prevent myocardial ischemia–reperfusion injury (Aldakkak et al., 2011; Montecucco et al., 2010). Moreover, cluster of studies 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ejphar European Journal of Pharmacology http://dx.doi.org/10.1016/j.ejphar.2014.04.026 0014-2999/& 2014 Published by Elsevier B.V. n Corresponding author. E-mail address: drrajaau@gmail.com (B. Raja). Please cite this article as: Senthamizhselvan, O., et al., Diosmin pretreatment improves cardiac function and suppresses oxidative stress in rat heart after ischemia/reperfusion. Eur J Pharmacol (2014), http://dx.doi.org/10.1016/j.ejphar.2014.04.026i European Journal of Pharmacology ∎ (∎∎∎∎) ∎∎∎–∎∎∎