Comparative Study of the Protective Effects of Citral, Thymoquinone, and Silymarin on Methotrexate-induced Cardiotoxicity in Rats

Abstract

Objectives: Methotrexate (MTX), an immunosuppressant and anti-cancer medication, can harm the heart. The goal of the current investigation was to assess the cardiotoxicity caused by MTX and the potential cardioprotective properties of silymarin, citral, and thymoquinone as antioxidants.

Methods: Forty-eight rats were divided into six groups, which included control, MTX, cosolvent, citral, thymoquinone, and silymarin groups. At the end of the study, the rats were anesthetized (ketamine and xylazine) and killed using CO2. Their blood samples were collected to measure the enzymatic activities of creatine kinase-myoglobin binding (CK-MB), creatine phosphokinase (CPK), and lactate dehydrogenase (LDH). Also, the heart tissue was sampled to determine the antioxidant capacity and examine the histopathology.

Results: The findings revealed that the activity of CPK, CK-MB, and LDH enzymes significantly reduced in the thymoquinone treatment group compared to the MTX group (p < 0.05). On the other hand, total antioxidant capacity was significantly increased in the thymoquinone group compared to the MTX group (p < 0.05). The pathological modifications (i.e. severe congestion, edema fluid, the presence of inflammatory cells around the blood vessels, mild to moderate hemorrhaging between cardiac muscle fibers) were seen in the MTX group. The treatment groups, particularly thymoquinone, did not experience any appreciable pathological changes.

Conclusion: The thymoquinone was found to have the strongest protective effect against the heart damage caused by MTX.

Keywords: cardiotoxicity; citral; methotrexate; silymarin; thymoquinone.

Figure 1

The effect of silymarin, citral and thymoquinone on serum creatine phosphokinase (CPK) concentration in rats under influences of Methotrexate (n = 8). ANOVA statistical test and Tukey’s post hoc test are performed and the results are presented as mean ± SEM (^ap < 0.05 compared to Methotrexate group).

Figure 2

The effect of silymarin, citral and thymoquinone on serum creatine kinase (CK-MB) concentration in rats under influences of Methotrexate (n = 8). ANOVA statistical test and Tukey’s post hoc test are performed and the results are presented as mean ± SEM (^ap < 0.05 compared to methotrexate group).

Figure 3

The effect of silymarin, citral and thymoquinone on serum concentration of lactate dehydrogenase (LDH) in rats under influences of Methotrexate (n = 8). ANOVA statistical test and Tukey’s post hoc test are performed and the results are presented as mean ± SEM (^ap < 0.05 compared to methotrexate group).

Figure 4

Histopathological examination of myocardia. (A) Normal structure and architecture of myocardia in healthy rats. (B) Severe vascular hemorrhage, congestion, edema fluid and mild presence of inflammatory cells in the heart tissue of methotrexate group rats. (C) Histological structure of cardiac muscle filaments or cells and their cytoplasm in the heart tissue of rats in the drug carrier group (H&E, 400×). (D) Vascular congestion and focal hemorrhages in the myocardial muscle fibers of heart tissue of citral group rats (H&E, 100×). (E) Cardiac muscle fibers without any pathological lesions in rats receiving silymarin (H&E, 400×). (F) Cardiac striated muscle fibers without any pathological lesions in thymoquinone group rats (H&E, 400×).

Figure 5

The effect of silymarin, citral and thymoquinone on cardiac tissue concentration of total antioxidant capacity (TAC) in rats under influences of Methotrexate (n = 6). The results of statistical test (ANOVA) and Tukey’s post hoc test are shown as mean ± SEM (^ap < 0.05 compared to methotrexate and drug carrier group).

Figure 6

The effect of silymarin, citral and thymoquinone on cardiac tissue concentration of total antioxidant capacity (MDA) in rats under influences of Methotrexate (n = 6). The results of statistical test (ANOVA) and Tukey’s post hoc test are shown as mean ± SEM (^ap < 0.05 compared to methotrexate group).