Dual therapy with allicin and metformin provides superior cardioprotection against doxorubicin-induced cardiotoxicity in rats compared to monotherapy

Abstract

Background: Doxorubicin is a widely used chemotherapeutic agent; however, its clinical utility is limited by dose-dependent cardiotoxicity. Existing cardioprotective strategies are insufficient, showing that there is a need for safer and more effective alternatives.

Objectives: This study evaluated the cardioprotective effects of metformin and allicin, individually and in combination, against doxorubicin-induced cardiotoxicity in rats.

Methods: Fifty adult male Wistar albino rats were randomized into five groups (n = 10 each): The control group was administered normal saline (2 mL/kg, intraperitoneally, on days 7, 14, and 21); the DOX-only group received doxorubicin (6 mg/kg, intraperitoneally, on days 7, 14, and 21; cumulative dose 18 mg/kg); the DOX + Allicin group was given allicin (40 mg/kg/day, orally), the DOX + Metformin group received metformin (300 mg/kg/day, orally), and the DOX + Allicin+ Metformin group received both agents at these doses. Treatments were given orally once daily for 21 days. On day 22, blood samples and cardiac tissues were collected for biochemical and histopathological evaluation. Parameters assessed included body and heart weights, serum cardiac biomarkers (CK-MB, LDH, cTn I), antioxidant defenses (GSH, CAT, GPx, SOD), and oxidative stress indices (MDA, NO).

Results: Both allicin and metformin significantly attenuated DOX-induced elevation of cardiac enzymes, with greater protection observed under combined therapy. Antioxidant markers (GSH, GPx, SOD, CAT, NO) increased significantly, whereas MDA levels decreased. Dual treatment produced superior effects compared to either agent alone, a finding further supported by marked histopathological improvement in cardiac tissues.

Conclusion: Metformin and allicin each conferred significant cardioprotection against doxorubicin-induced cardiotoxicity, evidenced by the restoration of cardiac enzymes, reduction of oxidative stress, and improvement in myocardial histoarchitecture. Notably, combined therapy produced greater biochemical and structural recovery than either monotherapy, highlighting its enhanced overall cardioprotective efficacy.

Keywords: allicin; antioxidant; cardioprotection; cardiotoxicity; doxorubicin; metformin; oxidative stress; rats.

FIGURE 1

Allicin, metformin, and their combination as modulators of body and relative heart weights in doxorubicin-induced cardiotoxicity in rats statistical analysis for body weight (A) was performed using two-way repeated-measures ANOVA (time × treatment) followed by Tukey’s post hoc test. Relative heart weight (B) was analyzed using one-way ANOVA followed by Tukey’s post hoc test. Data are presented as mean ± SD (n = 10). *p < 0.05 vs. control group.

FIGURE 2

Allicin, metformin, and their combination attenuate cardiac enzyme alterations in a rat model of doxorubicin-induced cardiotoxicity. (A) Creatine kinase-MB (CK-MB), (B) lactate dehydrogenase (LDH), and (C) cardiac troponin I (cTn-I). Data are presented as mean ± SD (n = 10). Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test. *p < 0.05 vs. control group, #p < 0.05 vs. DOX group.

FIGURE 3

Ameliorative role of allicin, metformin, and their combination on antioxidant biomarkers in doxorubicin-induced cardiotoxicity in rats. (A) Glutathione reductase (GSH), (B) Glutathione peroxidase (GPx), (C) Superoxidase dismutase, (D) Catalase (CAT). Data are presented as mean ± SD (n = 10). Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test. *p < 0.05 vs. control group, #p < 0.05 vs. DOX group, $p < 0.05 vs. DOX + Allicin group, @p < 0.05 vs. DOX + MET group.

FIGURE 4

Allicin, metformin, and their combination reduce lipid peroxidation (MDA levels) in a rat model of doxorubicin-induced cardiotoxicity. Data are presented as mean ± SD (n = 10). Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test. *p < 0.05 vs. control group, #p < 0.05 vs. DOX group, $p < 0.05 vs. DOX + Allicin group.

FIGURE 5

Allicin, metformin, and their combination restore nitric oxide levels in a rat model of doxorubicin-induced cardiotoxicity. Data are presented as mean ± SD (n = 10). Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test. *p < 0.05 vs. control group, #p < 0.05 vs. DOX group, $ p < 0.05 vs. DOX+ Allicin group.

FIGURE 6

Histological photomicrographs of cardio sections of tissue from experimental rats were stained with Hematoxylin and Eosin (H&E), showing: (A) Normal Control Group showed: The myocardial architecture was well-preserved, with regular, parallel alignment of cardiac muscle fibers. There were no signs of cellular infiltration, necrosis, or interstitial edema [400×] Scale bar (50 µm). (B) Doxorubicin (DOX)-Treated Group showed: pathological alterations. These included widespread degeneration (Green arrow); a moderate nuclear pyknosis (Yellow arrows); inflammatory cell infiltration (Black arrows); cytoplasmic vacuolization (Blue arrow) and necrosis cells (N) and moderate of cardiac fibers fragmentation (Red arrow); were observed [400×] [100×] Scale bars (50 µm). (C) Doxorubicin (DOX) + Allicin Group showed: moderate histological improvement compared to the DOX-only group. Partial restoration of fiber alignment and some structural alterations persisted, such as a few scattered inflammatory cells (Blue arrow) were observed; pyknotic nuclei (Black arrows); necrosis cells (N); and loss of myocardial cellular constituents (Black circle) [400×] Scale bars B= (50 µm). (D) Doxorubicin (DOX) + Metformin Group showed: reduction in inflammatory cell infiltration; a few pyknotic nuclei (blue arrows) mild necrotic cells (N) and a few muscle fibers having fragmentation (red arrow); were observed [400×] Scale bars B= (50 µm). (E) DOX + Allicin +Metformin Group showed: Cardiac muscle fibers were nearly restored to normal morphology, with well-organized structure, minimal vacuolization, and absence of inflammatory infiltration or necrosis [400×] Scale bars B= (50 µm).