Abstract:
Myocardial infarction is among the leading causes of death around the world. This condition is treated by reperfusion therapy which may cause myocardial ischemic reperfusion injury (IRI). Currently, there is no treatment for IRI. The purpose of this study was to determine the effect of Zingiber officinale on myocardial ischemic-reperfusion injury and to investigate its antithrombotic property. A laboratory based true experimental study design was employed. Fresh Z officinale rhizomes were subjected to methanol extraction, and the extract was dissolved in 5% DMSO. Qualitative phytochemical screening of the Z officinale extract was also conducted. Twenty five rats were divided into 5 groups and treated with; 5% DMSO, 10 mg/kg of aspirin, 50 mg/kg of Z officinale, 250 mg/kg of Z officinale and 500 mg/kg of Z officinale, all administered through oral gavage for 30 days. To assess the antithrombotic action, bleeding time (BT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), platelet count and calcium levels were determined after treatment. To assess cardio-protective effects, Langendorf perfused isolated hearts were subjected to ischemia and reperfusion and left ventricular developed pressure (LVDP), rate of contraction (+dP/dt), rate of relaxation (-dP/dt) and heart rate (HR) were measured. Pre ischemic and post-ischemic values of these contractile indices were then compared to assess the degree of myocardial recovery. Serum catalase activity was also determined. Finally, hearts were processed and stained with hematoxylin and eosin and examined microscopically. Results were analyzed using SPSS software version 21. Groups’ comparison was done using one way ANOVA. Results are expressed as Mean ± SEM and presented using tables and bar graphs. Flavonoids, alkaloids and steroids, were detected in the extract upon phytochemical screening. 500 mg/kg of Z officinale significantly prolonged bleeding time (P = 0.032). It however did not significantly affect platelet count (P = 0.084). There were no statistically significant differences between the groups in prothrombin time (P=0.987), activated partial thromboplastin time (P=0.637), thrombin time (P=0.427) and calcium levels (P=0.427). Left ventricular function was preserved better in the group treated with 500 mg/kg of Z officinale than other groups as shown by statistically significant differences in the percentage recovery of LVDP (P=0.04), dp/dtmax (P=0.036), dp/dtmin (P=0.047) and heart rate (P=0.041). Group treated with 500 mg/kg of Z officinale also had a statistically significant increase in serum catalase activity compared to other groups (P=0.032). Furthermore, there was a better preservation of myocardial histomorphorlogy in the groups treated with Z officinale than the Negative control upon microscopic examination. We conclude that methanol extract of Z officinale had significant cardio-protective and antithrombotic effects. It inhibited platelet function but had no statistically significant effect on coagulation. It also conferred protection against myocardial ischemic-reperfusion injury as demonstrated by statistically significant preservation of left ventricular contractile function following ischemia and reperfusion. We recommend further studies involving molecular characterization of the phytochemicals of Z officinale’s methanol extract that exert these actions.
