Introduction

Paraquat (PQ) is a powerful, non-selective herbicide that was first introduced in 1955. It’s widely used to help control weeds by acting as a desiccant and defoliant for crops. However, one of the concerning aspects of PQ is that non-target organisms can easily absorb it, making them vulnerable through ingestion, inhalation, skin contact, or eye exposure. In plants, toxicity of PQ arises from its ability to produce free radicals when it interacts with oxygen, which disrupts the photosynthesis process. In animals, PQ is rapidly distributed throughout various tissues and organs. Unlike some chemicals, it isn’t metabolized in the body; instead, it transforms into an unstable free radical. This radical is then re-oxidized, resulting in the formation of a superoxide anion and a cation, both of which are highly toxic to humans and animals alike1,2,3,4,5.

PQ is known as a potent free radical generator6 and one of the widely used agriculture herbicides worldwide7. Among the most serious poisonings related to this herbicide, we can mention accidental poisoning and intentional suicide, so PQ is a serious public health problem8. According to epidemiological data, PQ poisoning is responsible for more than 50% of pesticide-related fatality cases that affect organ systems including the respiratory, reproductive, neurobehavioral, and gastrointestinal systems9,10,11,12. Poisoning with a moderate concentration of PQ can cause serious heart, kidney, and liver failure within a few days to a few weeks13. Inflammation and oxidative stress play an essential role in the pathological processes of these changes14. The liver is the body’s primary organ for maintaining homeostasis between intracellular free radicals and the antioxidant defense system. Following PQ exposure, an excessive rise in free radicals and a reduction in antioxidant capacity are brought on by creating cellular superoxide anion, hydroxyl free radical, and nitric oxide (NO), which can result in oxidative stress, tissue damage, and liver malfunction15,16,17. It has been reported that PQ can cause many histopathological and biochemical changes in liver tissue18 Free radicals produced by PQ bind to important body molecules such as proteins, lipids, and DNA and cause liver dysfunction, so many patients poisoned with PQ suffer from hepatotoxicity19. Oxidative stress imbalance activates redox-sensitive signaling pathways, including nuclear factor erythroid-2 (Nrf-2) and nuclear factor-kappa B (NF-κB)20. With the increase of oxidative stress, Nrf-2 located in the cytoplasm is separated from Keap1 and migrates to the cell nucleus, which causes the activity of antioxidant enzymes21,22. Meanwhile, the NF-κB which is a transcription regulator also migrates into the nucleus and increases the expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1 beta (IL-β1)23. PQ-induced apoptosis has been shown to activate the intrinsic mitochondrial pathway by increasing pro-apoptotic and anti-apoptotic proteins (Bax/Bcl-2 ratio) and activating caspases by releasing cytochrome C from mitochondria. Bax induces cell death and Bcl-2 prevents Bax-induced apoptosis, so overexpression of Bcl-2 prevents PQ- induced apoptosis24,25.

Dimethyl fumarate (DMF), known as an anti-inflammatory and antioxidant drug, has been used in patients with multiple sclerosis26,27 and psoriasis28. DMF blocks the activity of the cellular immune system by inhibiting glycolysis29. The use of DMF treatment may be helpful for individuals with psoriasis because it activates the (Nuclear factor erythroid-derived 2-like 2) Nrf-2 pathway, which provides protection against oxidative stress30. DMF has been suggested to have a potential protective effect on the nervous system, which is believed to be due to its ability to activate the Nrf-2 pathway in astrocytes, oligodendrocytes, and neurons. This pathway is triggered by an initial increase in oxidative stress caused by DMF binding and depleting Glutathione (GSH), which leads to an increase in reactive oxygen species (ROS). However, this increase in ROS ultimately results in the activation of antioxidant gene transcription and an increase in intracellular GSH concentration, which can protect against further oxidative damage31. According to the many studies that have been conducted on the safety of DMF, digestive problems are one of the most unwanted side effects of this drug, however, an increase in serum liver factors, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT), has rarely been seen31,32,33,34. It has been reported that DMF improves liver function and antioxidant and inflammatory status by up-expression of antioxidant enzymes catalase (CAT) and glutamate cysteine ligase, as well as regulating a key inflammatory mediator known as NF-κB35. Also, DMF can regulate inflammatory pathways via inhibition of the Nrf-2 factor35,36. In this way, DMF has a common pathway with PQ herbicide, and it seems that the effects of increasing Nicotinamide adenine dinucleotide phosphate (NADPH) by DMF can be prevented in the treatment of adverse effects caused by the reduction of PQ. Considering that PQ is a multi-organ toxicant, the mechanisms of toxicity in different organs are important to investigate separately. In a study by our research team, the protective effects of DMF against pulmonary toxicity of PQ were investigated37. Therefore, knowing that the liver is one of the vital organs in the detoxification and metabolism of toxicants, it may also be exposed to the toxic effects of PQ11. Accordingly, the aim of the present study was to investigate the effects of DMF on the incidence of oxidative stress, apoptosis, and inflammation caused by PQ in the mouse liver.

Results

DMF effects on liver function biomarkers

In our study, we found that the activities of ALT, AST, and ALP were significantly elevated in the PQ treatment group when compared to the control group (P < 0.001). This elevation indicates potential hepatotoxicity associated with PQ exposure, reflecting liver damage or dysfunction. Notably, when PQ was co-treated with DMF at doses of 30 and 100 mg/kg, a significant decrease in serum enzyme activity levels was observed compared to the PQ group (P < 0.001). This reduction suggests that DMF may exert a protective effect against the liver damage induced by PQ, potentially restoring liver function or mitigating the toxic effects of PQ. These findings underscore the therapeutic potential of DMF in managing PQ-induced hepatotoxicity and warrant further investigation into its mechanisms of action and clinical applicability. A visual representation of these results is shown in Fig. 1.

Fig. 1
figure 1

The effects of DMF (dimethyl fumarate) on the activity level of (A): alanine aminotransferase: (ALT), (B): aspartate aminotransferase (AST), (C): alkaline phosphatase (ALP) in PQ (paraquat)-induced hepatotoxicity in mice (n = 7–8). *Significant difference compared to the control group (***P < 0.001). #Significant difference compared to the PQ group (###P < 0.001).

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DMF effects on oxidative stress factors

We observed a significant increase in the formation of TBARS and NO in the PQ treatment group compared to the control group (P < 0.001). As illustrated in (Fig. 2), PQ administration led to a marked decrease in TT and the activities of key antioxidant enzymes, including GPx, SOD, and CAT, relative to the control group (P < 0.001). Conversely, co-treatment with DMF at doses of 30 and 100 mg/kg significantly mitigated the increases in NO and TBARS levels and enhanced the activities of GPx, SOD, CAT, and restored TT levels compared to the PQ group. These results suggest that DMF may effectively counteract the oxidative stress induced by PQ, promoting antioxidant defenses and improving overall cellular health.

Fig. 2
figure 2

The effects of DMF (dimethyl fumarate) on the level of (A): TBARS (thiobarbituric acid reactive substances), (B): NO (nitric oxide), (C): TT (total thiol), (D): GPx (glutathione peroxidase), (E): SOD (superoxide dismutase), and (F): CAT (catalase) in PQ (paraquat)-induced liver injury in mice (n = 7–8). *Significant difference compared to the control group (***P < 0.001). #Significant difference compared to the PQ group (#P < 0.05, ##P < 0.01 and ###P < 0.001).

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DMF effects on inflammatory factors

We found that the levels of TNF-α and IL-1β were significantly elevated in the PQ treatment group when compared to the control group (P < 0.001). This increase indicates an inflammatory response triggered by PQ exposure. However, in the groups pretreated with DMF, we observed a significant reduction in the levels of both TNF-α and IL-1β compared to the PQ group, as shown in (Fig. 3). These findings suggest that DMF may possess anti-inflammatory properties that help to mitigate the inflammatory cytokine response associated with PQ toxicity and highlighting its potential role in protecting against inflammation-induced damage.

Fig. 3
figure 3

The effects of DMF (dimethyl fumarate) on the level of (A): tumor necrosis factor-α (TNF-α) and (B): interleukin-1β (IL-1β) in PQ (paraquat)-induced hepatotoxicity in mice (n = 7–8). *Significant difference compared to the control group (***P < 0.001). #Significant difference compared to PQ group (###P < 0.001).

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Effects of DMF on the expression of NF-κB, Nrf-2, Bax, and Bcl-2 proteins

As illustrated in (Fig. 4) the Nrf-2 to NF-κB proteins as regulators of oxidative stress and inflammation were significantly elevated in mice exposed to PQ. Treatment with DMF at doses of 30 and 100 mg/kg resulted in overexpression of Nrf-2, but reduced NF-κB levels compared to the PQ group. These changes suggest that DMF may enhance the cellular antioxidant response while suppressing pro-inflammatory signaling pathways. Furthermore, we observed that the expression level of the pro-apoptotic protein Bax was significantly increased in mice intoxicated with PQ (P < 0.001), whereas the anti-apoptotic protein Bcl-2 exhibited a significant decrease (P < 0.001). Notably, treatment with DMF resulted in a reduction in Bax expression (P < 0.001) and a significant elevation in Bcl-2 levels (P < 0.001) in mice administered 30 and 100 mg/kg DMF compared to the PQ group. In addition, the ratio of Bax to Bcl-2 in the PQ-treated group was markedly elevated compared to the control group (P < 0.001). However, DMF-treated groups (10, 30, and 100 mg/kg) remarkably prevented the increase in the ratio of Bax to Bcl-2 compared to the PQ group (P < 0.001). These findings indicate that DMF not only modulates the expression of key proteins involved in oxidative stress and inflammation but also plays a crucial role in regulating apoptosis, thereby potentially enhancing cell survival in PQ toxicity.

Fig. 4
figure 4

The effects of DMF (dimethyl fumarate) on protein expression of (A): Nrf-2, (B): NF-κB, (C): Bax, (D): Bcl-2 proteins, (E): Bax/Bcl-2 ratio and (F): Western blot bands in PQ (paraquat)-induced hepatotoxicity in mice (n = 3). *Significant difference compared to the control group (***P < 0.001). #Significant difference compared to the PQ group (##P < 0.01 and ###P < 0.001).

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Histopathologic findings

Histological examination of liver sections from control animals revealed a normal tissue structure, characterized by well-defined cellular structure and absence of pathological changes. In contrast, liver tissues from the PQ exposed group exhibited significant disruption of normal tissue patterns, including inflammatory cell infiltration and congestion. Notably, treatment with DMF at a dose of 100 mg/kg demonstrated a significant protective effect against PQ-induced histological damage. This treatment effectively reduced inflammatory cell infiltration and congestion within the liver tissue, as shown in (Fig. 5; Table 1). These findings suggest that DMF has the potential to preserve liver histology and mitigate the adverse effects of PQ exposure, highlighting its role as a protective agent in maintaining liver integrity under toxic conditions.

Fig. 5
figure 5

The effects of DMF (dimethyl fumarate) on histopathological changes and lesions of in PQ (paraquat)-induced hepatotoxicity in mice. The effects of DMF are obvious in H&E. I: infiltration of inflammatory cells; C: congestion. Magnification × 250.

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Table 1 The effects of DMF (dimethyl fumarate) on the infiltration of inflammatory cells and congestion in PQ (paraquat)-induced hepatotoxicity in mice.
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Discussion

Suicide and accidental poisoning with bipyridinium herbicides such as PQ quickly cause liver, kidney, and lung tissue damage38 By damaging the lipid cell membrane and lipid peroxidation, PQ causes widespread and multisystem toxicity in the body39. It has been shown in various clinical studies that PQ causes severe toxicity to various organs, including the liver40,41. Treatment of PQ poisoning is difficult due to its rapid distribution with a distribution volume of 1.2–1.6 L/kg in the liver, muscle, kidney, and lung42. Due to the mentioned reason, if PQ poisoning is not treated in a timely manner, the accumulation of PQ in the body can lead to rapid liver failure43. There is still no specific antidote for treatment, therefore the various proposed treatments have always been considered according to the mechanism of PQ toxicity40,42. In animal modeling studies, PQ administration with an acute dose in mice causes necrosis and inflammation of the liver due to oxidative damage to cells and the production of free radicals such as superoxide onions, hydrogen peroxide, hydroxyl free radicals, and peroxynitrite. Oxidative stress is one of the most important damage factors that leads to lipid peroxidation, mitochondrial membrane damage, cell death, and massive toxicity44,45,46. The redox cycle of PQ disrupts important biochemical processes by preventing the reduction of NADP+ to NADPH in the region of the electron transport chain, and induces GSH reduction and lipid peroxidation47, which can cause oxidative stress. Excessive production of ROS in the presence of PQ results in rapid and prolonged oxidation of NADPH, which is primarily caused by the cyclic reduction and reoxidation of PQ48. This oxidative reaction leads to significant consumption of NADPH, as it serves as a cofactor for glutathione reductase in the regeneration of oxidized glutathione (GSSG) back to its reduced form (GSH)49. As a consequence, the levels of intracellular SH groups decrease due to the oxidation of GSH, resulting in the formation of mixed disulfides between glutathione and protein thiols50. It has been reported that PQ increases the activity level of serum enzymes due to oxidative damage to liver cells and many pathological conditions such as liver and kidney damage, cancer, and diabetes51,52. In the study conducted by Semeniuk et al., ALT and AST increased in PQ group and decreased in genistein treatment groups53. Also, in a study that was induced by ischemia’s liver injury; Liver enzymes, including AST and ALT, increased, and DMF has had good recovery effects on damage54. The results of the present study show that the administration of PQ increased the serum enzymes AST, ALT, and ALP. However, a decrease in the activity of liver enzymes was observed in the group treated with DMF.

Inflammation and oxidative stress play important roles in the pathological processes of these changes. In addition to inducing oxidative stress, free oxygen radicals are responsible for direct cell damage with the regulated synthesis of nitrite oxide, which ultimately causes inflammation and tissue destruction. In the referenced studies, the group receiving PQ increased NO, and it decreased in the treatment groups in a dose-dependent manner55,56. DMF has been shown in a study to have a beneficial effect on acetaminophen hepatotoxicity by raising SOD and TT levels while lowering NO and TBARS57. As the results of the present study, DMF is a good antioxidant and reducing agent that could preserve the cellular and extracellular content of glutathione and NADPH-dependent enzyme mechanisms and glutathione enzyme activity. The results of the present study demonstrate that PQ reduces the TT, activity of antioxidant enzymes like SOD and CAT and subsequently increases TBARS, which play a role in detoxifying free radicals, and in this way, antioxidant enzymes do have not the capacity to remove oxygen free radicals then the amount of lipid peroxidation increases. Under oxidative stress, Nrf-2 is dissociated from Keap1 and subsequently moves into the nucleus, where it binds to the antioxidant response element (ARE) sequence, thereby activating the Nrf-2-ARE pathway. NF-κB serves as a key regulator of inflammatory responses, driving the expression of numerous pro-inflammatory genes. In the presence of oxidative stress, IκBα proteins undergo degradation through polyubiquitination following phosphorylation, allowing NF-κB to be released. NF-κB translocated to the nucleus, where it binds to its specific DNA response elements, resulting in the transcription of pro-inflammatory mediators. The crosstalk between Nrf-2 and NF-κB in the context of oxidative stress and inflammation is significant. When Nrf-2 translocates to the nucleus and binds to the ARE sequence, it enhances the expression of various antioxidant enzymes (such as SOD, CAT, GPx). Additionally, Nrf-2 can reduce the degradation of IκB-α, thereby supporting antioxidant defenses and potentially functioning independently of ROS. Subsequently, NF-κB nuclear translocation is suppressed. NF-κB has the ability to elevate levels of pro-inflammatory cytokines (such as TNF-α, IL-1β, IL-6)58. The Nrf-2/ARE pathway is considered an important signaling pathway related to antioxidant activity, but NF-κB is known as a pro-inflammatory factor59 that can activate cytokines like TNF-α and IL-1β. In several studies, Nrf-2 upregulation against oxidative stress conditions has been pointed out as a key defense factor against free radicals60,61. In Qian et al.‘s study, the expression of Nrf-2 was significantly increased in PQ-induced lung toxicity62. In this study, PQ increased the expression of Nrf-2 protein, which indicates the activity of the defense system to create compensatory mechanisms against oxidative stress of acute PQ toxicity. The results of the protective effect of DMF in the present study are consistent with the evidence of previous studies and caused a significant increase in Nrf-2 in the treatment groups compared to the PQ group. NF-κB increased in the group receiving PQ, which caused an increase in the levels of TNF-α and IL-1β. DMF, as an anti-inflammatory agent, was able to inhibit PQ-induced inflammation in a dose-dependent manner63,64. In the Abdelrahman and Abdel-Rahman study, the TNF- α factor increased significantly in the group treated with acetaminophen, while it decreased in the group treated with dimethyl fumarate. In our study, this is also similar to the mentioned study57. DMF has been reported in past studies to modulate the Nrf-2 pathway as well as the nuclear factor NF-κB65. Bax is a pro-apoptotic member of the Bcl-2 family that promotes apoptosis by forming pores in the mitochondrial membrane, leading to the release of cytochrome c and activation of downstream caspases. In contrast, Bcl-2 is an anti-apoptotic protein that inhibits Bax’s activity, preventing mitochondrial permeability transition and promoting cell survival. During hepatotoxic events, the ratio of Bax to Bcl-2 can rise by increased Bax expression and decreased Bcl-2 levels. This apoptotic signaling pathway, contributing to liver cell death and exacerbating liver injury66. In our findings, exposure to PQ was shown to increase the Bax/Bcl-2 ratio and shift the balance towards apoptosis. This alteration enhances oxidative stress within the cells, contributing to mitochondrial dysfunction and cell death. Our study corroborates previous research that highlights the significant interplay between oxidative stress and the apoptotic pathway, emphasizing the importance of these molecular changes in understanding the mechanisms underlying cellular responses to environmental stressors67,68,69. In many studies, PQ has caused inflammation in the liver tissue, and antioxidants have been able to reduce this inflammation70,71,72. The histopathological findings in our study show that PQ has led to the damage to mouse liver tissue, these damages are observed due to the infiltration of inflammatory cells and vascular congestion in the group receiving PQ.

Materials and methods

Chemicals

Most of the materials needed for research, including paraquat, dimethyl fumarate, thiobarbituric acid (TBA), Ellman’s Reagent, Bradford solution reagent, phosphate buffered saline, trichloroacetic acid, and phosphoric acid were obtained from Sigma Aldrich Company. All kits used for glutathione peroxidase (GPx) and superoxide dismutase (SOD) (Catalog Number: ZB-SOD-96 A /48A, NO (Catalog Number: ZB-NO-96 A/48A (and TNF-α (Cat. No: ZB-10082 C-H9648) tests were purchased from ZellBio Company. BT lab kit was used for IL-1β (Catalog Number: E0192Mo) test. Kits for measuring serum factors were purchased from Pars Azmoon Company. Bax (catalog number: sc-7480), anti-rabbit lgG (catalog number: sc-2357) and Bcl-2 (catalog number: sc-7382) antibodies were purchased from Santa Cruz Biotechnology company. GAPDH (catalog number: #5174), Nrf-2 (catalog number: #12721), NF-κB (catalog number: #8242), antibodies were purchased from Cell Signaling Technology Company.

Animals

Adult male NMRI mice (6–8 weeks of age) and (weight 23–27 g) were obtained from the Center of Animal House of Ahvaz Jundishapur University of Medical Sciences (AJUMS), Ahvaz, Iran. Before starting the experiment, to accustom the animals to the laboratory environment conditions such as lighting cycle (12:12 h), temperature regulation (22–25 °C), and free access to food and water for 7 days were provided. The study received approval from the Ethical Committee of Ahvaz Jundishapur University of Medical Science, which is in accordance with the ARRIVE guidelines as well as the instructions of the National Institute of Health (NIH) for the care and use of laboratory animals. The working methods of animal experiments and euthanasia were approved by the AJUMS ethics committee (Ethics approval ID: IR.AJUMS.ABHC.REC.1401.031).

Experimental method

Animals were randomly placed in different groups: a control group, a DMF group, a PQ group, and three DMF pretreatment groups. Each group consisted of 7–8 mice. Mice in the DMF-treated groups received oral DMF in 10% DMSO as a vehicle at doses of 10, 30, and 100 mg/kg/day35, for seven consecutive days (four days before and three days after PQ administration) (Fig. 6). Mice in PQ and DMF pretreated groups were intraperitoneally injected just with a single dose of 30 mg/kg PQ73. Based on the strict ethical protocols of working with laboratory animals and with the presence of selected observers from the AJUMS, mice were anesthetized with ketamine (90 mg/kg) and xylazine (10 mg/kg)74,75, intraperitoneally. Samples of blood were obtained after heart puncture. Performing of deep anesthesia, exsanguination, and disruption of the diaphragm induce animal euthanasia. Collected sera were used to measure liver enzyme activity. After collecting the liver tissue, one part was stored in phosphate-buffered formalin solution (10%) for sliding and checking histological criteria by the histologist, and the other parts were frozen at − 70 °C until the subsequent evaluation of hepatic markers. The protein concentration of the samples was measured using the standard Bradford method76.

Fig. 6
figure 6

Scheme of experimental protocol to study ameliorative effects of DMF (dimethyl fumarate) on PQ (paraquat)-induced of the liver injury in mice. Mice were pretreated with DMF (10, 30 and 100 mg/kg) or vehicle (10% DMSO in saline) orally 4 days before and continued 3 days after paraquat administration.

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Liver tissue preparation

Samples were homogenized (1000 rpm) in phosphate buffer saline at a ratio (1:10 w/v) for 3 min. Then, the homogenized samples were centrifuged (8000 × g (for 10 min. In the next step, the tissues were sedimented, and the supernatants were collected and transferred to microtubes. To avoid damaging the samples, all steps were performed on ice and in the presence of a protease inhibitor.

Biochemical assays

Hepatic function biomarkers

After collecting the sera, the activities of AST, alkaline phosphatase (ALP), and ALT were assessed based on the kit protocols of the manufacturer.

Hepatic oxidative stress

The measurement of total thiol (TT) level77, thiobarbituric acid reactive substances (TBARS) level78, and CAT activity79 were performed according to mentioned studies. The analysis of colorimetric tests like NO, SOD and GPX were performed according to the method provided by the ZellBio manufacturer and read with plate reader.

Hepatic cytokine

To measure IL-1β and TNF-α in the liver supernatant samples, the methods of BT lab and ZellBio kits were used respectively.

Hepatic Western blot assay

Liver tissue was homogenized in RIPA lysis buffer with 1mM phenylmethylsulphonyl fluoride. Then the homogenates were centrifuged for 10 min at, 14,000 × g and the supernatants were transferred to new microtubes. The protein concentration of the supernatant was measured by the Bradford method, and the samples were kept at − 70 °C until further analysis. Fifty µg proteins were loaded with 10% SDS-PAGE and transferred to the nitrocellulose membrane. The membranes were blocked with 5% Skim Milk for 2 h and then incubated overnight with primary antibodies against GAPDH, Nrf-2, NF-κB, Bcl-2, and Bax at 4 ℃. After two washes, the membrane was incubated with anti-rabbit lgG for 2 h. Finally, the immunoreactive bands were detected using the Excellent Chemiluminescent Substrate (ECL) kit and quantified using JS 2000 (BonninTec, China) scanner. The protein expressions of Nrf-2, NF-κB, Bcl-2, and Bax were performed by analyzing the density of target proteins to GAPDH.

Histological procedure

For histopathological evaluation, liver tissue was fixed in a formalin solution and embedded in paraffin. The paraffin samples were sectioned at a thickness of 4 μm, placed on glass slides, and stained with H&E. Three slides were prepared from each animal tissue, and 5 microscopic fields from each slide were randomly scored numerically including: no lesion (grade 0), mild lesion (grade 1), moderate lesion (grade 2), and severe lesion (grade 3)80.

Statistical method

Data are shown as mean ± standard deviation. The data set of this research was compared using one-way analysis of variance (ANOVA) with Tukey’s multiple comparisons as a post hoc test. P values < 0.05 were considered statistically significant. All these analyses were performed with Prism 9 software.

Limitations

This study provides valuable insights into the potential protective effects of DMF against PQ-induced liver toxicity, but has limitations that should be considered. One limitation of this study is that we measured total protein expression of NF-κB and Nrf-2 without distinguishing between their phosphorylated or nuclear forms, which are indicators of their functional activity. However, alterations in the downstream pathway components of these factors may suggest the involvement of their active forms. Additionally, while Bax and Bcl-2 protein expressions were assessed as apoptosis markers, the study did not evaluate caspase-3 and caspase-9, key mediators in the apoptotic cascade. Future research should include these proteins and complementary methods like the TUNEL assay to provide direct evidence of apoptosis. Despite these limitations, the Bax/Bcl-2 ratio remains a valuable indicator supporting the study’s conclusions.

Conclusion

PQ inhibits antioxidant enzymes, induces lipid peroxidation, inflammation, and apoptosis in the liver, which ultimately leads to liver dysfunction (Fig. 7). Due to the positive effects of DMF as an anti-inflammatory, antioxidant, and antiapoptotic agent, it can be used against hepatotoxicity caused by PQ. Therefore, antioxidants and immunosuppressive drugs such as DMF, as an FDA-approved drug, may be suggested as effective and promising agent against PQ toxicity.

Fig. 7
figure 7

Graphical abstract shows the effects of dimethyl fumarate on paraquat-induced hepatotoxicity in mice. Parts of the graphical abstract were drawn by using pictures from Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 3.0 unported license (https:/ /creativecommons.org/licenses/by/3.0/).

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