Targeting Autoimmune Myocarditis with Lemon Balm Extract: In Vivo Molecular Approach

Figure 1. Representative M-mode echocardiograms of all experimental groups in the EAM model. Echocardiograms of rats belonging to the following groups (a) CTRL; (b) EAM; (c) LBE50; (d) LBE100; (e) LBE200. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg, or 200 mg/kg. Yellow markings indicate LVIDd (left ventricular internal diameter at end-diastole), while green markings indicate LVIDs (left ventricular internal diameter at end-systole).

Figure 2. Effects of LBE on the level of prooxidants (a) O2−—superoxide anion radical (b) H2O2—hydrogen peroxide (c) NO2− nitrites (d) TBARS—thiobarbituric acid reactive substances. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level p < 0.05 compared to * CTRL group; # EAM group. Data are presented as means ± standard deviation (X ± SD).

Figure 3. Effects of LBE on antioxidants. (a) SOD—superoxide dismutase (b) CAT—catalase (c) GSH—reduced glutathione. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level p < 0.05 compared to * CTRL group; # EAM group; ¶ LBE50 group. Data are presented as means ± standard deviation (X ± SD).

Figure 4. Effects of LBE on cardiac biochemical markers. (a) TnI—troponin I (b) TnT—troponin T (c) CK/MB—creatine kinase MB. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level p < 0.05 compared to * CTRL group. Data are presented as means ± standard deviation (X ± SD).

Figure 5. Effects of LBE on the level of cytokines. (a) TNF-alpha—tumor necrosis factor (b) IL1b–interleukin 1 beta (c) IL-6—interleukin 6 (d) IL-4—interleukin 4 (e) IL-10—interleukin 4 (f) IL17—interleukine 10 (g) TGFb-TGF beta. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level p < 0.05 compared to a CTRL group; b EAM group; c LBE50 group. Data are presented as means ± standard deviation (X ± SD).

Figure 6. Effects of LBE on the gene expression in myocardium. (a) SOD-1—superoxide dismutase 1 (b) SOD-2—superoxide dismutase 2 (c) NF-kb—nuclear factor kappa b (d) IL17—interleukin 17 (e) Bax (f) Bcl2. CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level p < 0.05 compared to a CTRL group; b EAM group; c LBE50 group, d LBE50 group. Data are presented as means ± standard deviation (X ± SD).

Figure 7. Histological analysis of the heart. tunnel assay, Sirius red stainin and hematoxylin eosin staining. (a) collagen content; (b) inflammatory infiltrate. Magnification 20× scale bar = 50 μm CTRL—healthy non-treated rats; EAM—rats with experimental autoimmune myocarditis; LBE50, LBE100 and LBE200—rats with experimental autoimmune myocarditis treated with lemon balm extract in a dose of 50 mg/kg, 100 mg/kg or 200 mg/kg. Statistical significance at the level of 0.05: a—compared to CTRL; b—compared to EAM; c—compared to LBE50; d—compared to LBE100 groups.