Cardioprotective Effects of Essential Oil of Lavandula angustifolia on Isoproterenol-induced Acute Myocardial Infarction in Rat

Abstract

Myocardial infarction (MI) is a common presentation of the ischemic heart disease. Lavandula angustifolia is an herbaceous plant with antioxidative effects. This study was designed to investigate the cardioprotective effects of lavandula angustifolia essential oil against isoproterenol-induced MI in rats. The dried sample was subjected to hydrodistillation by using a Clevenger and the oils were dried over anhydrous Na2SO4. Male Wistar rats were assigned to 6 groups of control, sham, isoproterenol and treatment with 5, 10, 20 mg/Kg of the essential oil. MI was induced by subcutaneous injection of Isoproterenol (100 mg/Kg) for 3 consecutive days at an interval of 24 h. The essential oil was given intraperitoneally every 24 h started at MI induction. Following anesthesia, hemodynamic parameters were measured. After sacrificing the animals, the hearts were removed to measure the heart to body weight ratio and histopathological examination. Myeloperoxidase (MPO) and Malondialdehyde (MDA) were measured in heart tissues for evaluating the activity of neutrophils and lipid peroxidation, respectively. The essential oil amended ECG pattern by suppressing ST-segment elevation and increasing R-amplitude. 10 mg/Kg of the essential oil significantly decreased heart to body weight ratio (P<0.001) and the elevation of MDA and MPO in myocardium, it also increased dp/dtmax from 2793 ± 210 to 4488 ± 253 mmHg/sec (P<0.001), and 20 mg/Kg of it significantly lowered LVEDP from 14 ± 3.43 to 4.3 ± 0.83 mmHg (P<0.001).The results demonstrated that L. angustifolia protects myocardium against isoproterenol-induced MI that it could be related to its antioxidant properties.

Keywords: Antioxidant; Isoproterenol; L. angustifolia; Myocardial infarction.

Figure 1

The effects of essential oil of L. angustifolia on electrocardiographic pattern and changes (recorded from limb lead II) in control, isoproterenol and Lavandula groups. Iso: Isoproterenol, Lav: L. angustifolia essential oil.

Figure 2

Effects of the essential oil of L. angustifolia on ST-segment height and R-amplitude. Values are mean ± SEM (n=6). ᵃP<0.001 from respective control value, ***P<0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test. Iso: Isoproterenol, Lav: L. angustifolia essential oil.

Figure 3

Left ventricular maximal and minimal rates of pressure increase (LVdp/dtmax, LVdp/dtmin) in the control group and in the rats treated with isoproterenol alone (rats with myocardial infarction), L. angustifolia alone (Sham), and Isoproterenol plus L. angustifolia. Values are mean±SEM (n=6). ªp<0.001 , ᵇp<0.01 ,ᶜp<0.05 from respective control value; *p < 0.05, **p < 0.01; ***p < 0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test.

Figure 4

The effects of L. angustifolia essential oil on Heart weight (HW) to Body weight (BW) ratios. Data are expressed as mean±SEM (n=6). ªp<0.001 , ᵇp<0.01 ,ᶜp<0.05 from respective control value; *p < 0.05, **p < 0.01; ***p < 0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test. Iso: Isoproterenol, Lav: L. angustifolia essential oil.

Figure 5

Photomicrographs of sections of rat cardiac apexes. Heart tissue of a rat subcutaneously injected with isoproterenol alone shows intensive cardiomyocyte necrosis and increased edematous intramuscular space. Treatment with L. angustifolia demonstrates a marked improvement. Iso: Isoproterenol. Lav: L. angustifolia (H&E).

Figure 6

The effects of L. angustifolia administration on grading of histopathological changes in rats’s cardiac apex tissues (scores 1, 2, 3, and 4 show low, moderate, high and intensive pathological changes respectively). Data are expressed as mean ± sem (n =6). ªp <0.001 from respective control value; *p < 0.05; **p < 0.01; ***p < 0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test. Iso: Isoproterenol, Lav: L. angustifolia essential oil.

Figure 7

The effects of L. angustifolia essential oil on malondialdehyde (MDA). Data are expressed as mean±SEM (n=6). ªp<0.001 , ᵇp<0.01 ,ᶜp<0.05 from respective control value; *p < 0.05, **p < 0.01; ***p < 0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test. Iso: Isoproterenol, Lav: L. angustifolia essential oil.

Figure 8

The effects of L. angustifolia essential oil on myeloperoxidase (MPO). Data are expressed as mean±SEM (n=6). ªp<0.001 , ᵇp<0.01 ,ᶜp<0.05 from respective control value; *p < 0.05, **p < 0.01; ***p < 0.001 as compared with isoproterenol treated group using one way ANOVA with Student-Newman-Keuls post hoc test. Iso: Isoproterenol, Lav: L. angustifolia essential oil.