Rosemary supplementation (Rosmarinus oficinallis L.) attenuates cardiac remodeling after myocardial infarction in rats

Abstract

Background: Myocardial infarction (MI) is one of the leading causes of morbidity and mortality worldwide. Dietary intervention on adverse cardiac remodeling after MI has significant clinical relevance. Rosemary leaves are a natural product with antioxidant/anti-inflammatory properties, but its effect on morphology and ventricular function after MI is unknown.

Methods and results: To determine the effect of the dietary supplementation of rosemary leaves on cardiac remodeling after MI, male Wistar rats were divided into 6 groups after sham procedure or experimental induced MI: 1) Sham group fed standard chow (SR0, n = 23); 2) Sham group fed standard chow supplemented with 0.02% rosemary (R002) (SR002, n = 23); 3) Sham group fed standard chow supplemented with 0.2% rosemary (R02) (SR02, n = 22); 4) group submitted to MI and fed standard chow (IR0, n = 13); 5) group submitted to MI and fed standard chow supplemented with R002 (IR002, n = 8); and 6) group submitted to MI and fed standard chow supplemented with R02 (IR02, n = 9). After 3 months of the treatment, systolic pressure evaluation, echocardiography and euthanasia were performed. Left ventricular samples were evaluated for: fibrosis, cytokine levels, apoptosis, energy metabolism enzymes, and oxidative stress. Rosemary dietary supplementation attenuated cardiac remodeling by improving energy metabolism and decreasing oxidative stress. Rosemary supplementation of 0.02% improved diastolic function and reduced hypertrophy after MI. Regarding rosemary dose, 0.02% and 0.2% for rats are equivalent to 11 mg and 110 mg for humans, respectively.

Conclusion: Our findings support further investigations of the rosemary use as adjuvant therapy in adverse cardiac remodeling.

Fig 1. Study design.

Fig 2. Echocardiographic study and blood systolic pressure in Sham and infarcted rats with and without rosemary supplementation.

A. LA/BW: left atrial diameter indexed for body weight (p = 0.001); B. LA/AO: left atrial diameter indexed for aortic diameter (p = 0.024); C. EDT: E wave deceleration time (p = 0.004); D. BP: blood systolic pressure (p = 0.343). Data are expressed as the mean ± SEM. Asterisks (*) represent significant difference between groups (p<0.05). Sample size: SR0 = 23; SR002 = 23; SR02 = 22; IR0 = 13; IR002 = 8; and IR02 = 9.

Fig 3. Morphometric study in Sham and infarcted rats with and without rosemary supplementation.

A. CSA: cardiomyocyte cross-sectional area (p<0.001); B. Microscopic images of CSA H&E stained (evidenced with arrows) of groups SR0, IR0, IR002 and IR02; C. % collagen: p = 0.035; D. Microscopic images of myocytes Picrosirius red stained for collagen (red marks in images) of SR0, IR0, IR002 and IR02. Data are expressed as the mean ± SEM. Asterisks (*) represent significant difference between groups (p<0.05). Sample size: SR0 = 23; SR002 = 23; SR02 = 22; IR0 = 13; IR002 = 8; and IR02 = 9.

Fig 4. Energy metabolism enzymes in Sham and infarcted rats with and without rosemary supplementation.

LDH activity: lactate dehydrogenase activity (p = 0.014); CS activity: citrate synthase activity (p<0.001); OHADH activity: 3-hydroxyacyl coenzyme-A dehydrogenase activity (p<0.001); ATP sinthase activity (p = 0.039); Complex I activity: p = 0.004; Complex II activity: p<0.001. Data are expressed as the mean ± SEM. Asterisks (*) represent significant difference between groups (P<0.05). Sample size: SR0 = 8; SR002 = 8; SR02 = 8; IR0 = 10; IR002 = 7; and IR02 = 8.

Fig 5. Oxidative stress enzymes in Sham and infarcted rats with and without rosemary supplementation.

LH: lipid hydroperoxide concentration (p<0.001); SOD activity: superoxide dismutase activity (p<0.001); GSH-Px activity: glutathione peroxidase activity (p = 0.031). Data are expressed as the mean ± SEM. Asterisks (*) represent significant difference between groups (P<0.05). Sample size: SR0 = 8; SR002 = 8; SR02 = 8; IR0 = 10; IR002 = 7; and IR02 = 8.

Fig 6. Nrf2 expression in Sham and infarcted rats by Western blot.

A. Nrf2 expression; B. representative western blot of Nrf2 expression. Nrf2: nuclear erithroid factor 2; GAPDH glyceraldehyde-3-phosphate dehydrogenase. Since no interaction between factors was observed, the effect of myocardial infarction is represented. Data are expressed as the mean ± SEM. Asterisks (*) represent significant difference between groups. Sample size: SR0 = 10; SR002 = 10; SR02 = 10; IR0 = 10; IR002 = 8; and IR02 = 9.