effect of thymoquinone, an active component of Nigella sativa, on isoproterenol induced myocardial injury

ABSTRACT

Myocardial injury constitutes a major cause of morbidity and mortality in humans. Present study aimed to investigate protective role of thymoquinone, which is an active principle of Nigella sativa [N. sativa] seed [Commonly called as black seed], in isoproterenol induced myocardial injury, a classical example of excess catecholamines related coronary insufficiency and 'stress cardiomyopathy'. Thymoquinone, in olive oil, was administered orally [12.5, 25 and 50mg/kg] to three groups of Wistar albino rats for 7 days, while two control groups were given plain olive oil. Thereafter, thymoquinone receiving groups and one control group were injected, subcutaneously, with isoproterenol [125mg/kg] for 2 days. Myocardial injury was assessed by biochemical markers [plasma LDH, TBARS, GR and SOD and myocardial GSH/GSSG ratio] and cardiac histopathology. Plasma LDH, TBARS and GR increased in control groups receiving isoproterenol, while there was a dose related decrease in these markers in thymoquinone treated groups, down to levels in controls given olive oil only. Decrease in plasma SOD and myocardial GSH/GSSG ratio and histological changes produced with isoproternol were also reversed in thymoquinone treated rats. Results of our study revealed that thymoquinone protects the heart from injury induced by isoproterenol