The role of lipid peroxidation in liver damage

Therapeutic Potential of Nutraceuticals against Drug-Induced Liver Injury

Drug-induced liver injury (DILI) continues to be a major concern in clinical practice, thus necessitating a need for novel therapeutic approaches to alleviate its impact on hepatic function. This review investigates the therapeutic potential of nutraceuticals against DILI, focusing on examining the underlying molecular mechanisms and cellular pathways. In preclinical and clinical studies, nutraceuticals, such as silymarin, curcumin, and N-acetylcysteine, have demonstrated remarkable efficacy in attenuating liver injury induced by diverse pharmaceutical agents. The molecular mechanisms underlying these hepatoprotective effects involve modulation of oxidative stress, inflammation, and apoptotic pathways. Furthermore, this review examines cellular routes affected by these nutritional components focusing on their influence on hepatocytes, Kupffer cells, and stellate cells. Key evidence highlights that autophagy modulation as well as unfolded protein response are essential cellular processes through which nutraceuticals exert their cytoprotective functions. In conclusion, nutraceuticals are emerging as promising therapeutic agents for mitigating DILI, by targeting different molecular pathways along with cell processes involved in it concurrently.

Alleviation of Copper-Induced Hepatotoxicity by Bergenin: Diminution of Oxidative Stress, Inflammation, and Apoptosis via Targeting SIRT1/FOXO3a/NF-κB Axes and p38 MAPK Signaling

Despite its biological importance, excess copper induces organ damage, especially to the liver. Disruption of critical signaling cascades that control redox status, inflammatory responses, and cellular apoptosis significantly contributes to the copper-induced hepatotoxicity. The present work explored the hepatoprotective ability of bergenin against the copper-induced hepatotoxicity using male Wistar rats as a mammalian model. The results revealed that bergenin suppressed the copper-evoked histopathological changes and hepatocellular necrosis as indicated by decreased activity of the liver enzymes ALT and AST in the sera of the copper-intoxicated rats. It decreased hepatic copper content and the copper-induced oxidative stress as revealed by reduced lipid peroxidation and improved activity of the antioxidant enzymes thioredoxin reductase, glutathione peroxidase, catalase, and superoxide dismutase. Bergenin downregulated the inflammatory cytokines TNF-α and IL-6, and the inflammatory cell infiltration to the liver tissues. Additionally, it inhibited the copper-induced apoptosis as indicated by significant reduction in caspase-3 activity. At the molecular level, bergenin activated the antioxidant transcription factor FOXO3a, inhibited the nuclear translocation of the inflammatory transcription factor NF-κB, and suppressed the inflammatory signaling molecules p38 MAPK and c-Fos. Interestingly, bergenin improved the expression of the anti-apoptotic protein Bcl2 and reduced the pro-apoptotic protein BAX. Bergenin markedly enhanced the expression of the histone deacetylase protein SIRT1 that regulates activity of NF-κB and FOXO3a. Collectively, these findings highlight the alleviating activity of bergenin against the copper-induced hepatotoxicity via controlling oxidative stress, inflammation, and apoptosis potentially through upregulation of SIRT1, activation of FOXO3a along with suppression of NF-κB and p38 MAPK signaling.

Loss of cis-PTase function in the liver promotes a highly penetrant form of fatty liver disease that rapidly transitions to hepatocellular carcinoma

Obesity-linked fatty liver is a significant risk factor for hepatocellular carcinoma (HCC)1,2; however, the molecular mechanisms underlying the transition from non-alcoholic fatty liver disease (NAFLD) to HCC remains unclear. The present study explores the role of the endoplasmic reticulum (ER)-associated protein NgBR, an essential component of the cis-prenyltransferases (cis-PTase) enzyme3, in chronic liver disease. Here we show that genetic depletion of NgBR in hepatocytes of mice (N-LKO) intensifies triacylglycerol (TAG) accumulation, inflammatory responses, ER/oxidative stress, and liver fibrosis, ultimately resulting in HCC development with 100% penetrance after four months on a high-fat diet. Comprehensive genomic and single cell transcriptomic atlas from affected livers provides a detailed molecular analysis of the transition from liver pathophysiology to HCC development. Importantly, pharmacological inhibition of diacylglycerol acyltransferase-2 (DGAT2), a key enzyme in hepatic TAG synthesis, abrogates diet-induced liver damage and HCC burden in N-LKO mice. Overall, our findings establish NgBR/cis-PTase as a critical suppressor of NAFLD-HCC conversion and suggests that DGAT2 inhibition may serve as a promising therapeutic approach to delay HCC formation in patients with advanced non-alcoholic steatohepatitis (NASH).

Increased Blood Concentrations of Malondialdehyde in Plasmodium Infection: A Systematic Review and Meta-Analysis

Several studies have evaluated the relationship between malondialdehyde (MDA) concentrations and Plasmodium infections; however, the findings remain inconclusive. This study synthesized differences in MDA concentrations among patients with different levels of clinical severity, uninfected controls, and different Plasmodium species. The research protocol was registered in PROSPERO (CRD42023393540). Systematic literature searches for relevant studies were performed using the Embase, MEDLINE, Ovid, ProQuest, PubMed, Scopus, and Google Scholar databases. Qualitative and quantitative syntheses (meta-analyses) of distinct MDA concentrations between the disease groups were performed. Twenty-three studies met the eligibility criteria and were included in the systematic review. Overall, MDA concentrations were significantly elevated in participants with malaria relative to uninfected controls (p < 0.01, Cohen d: 2.51, 95% confidence interval (CI): 1.88-3.14, I2: 96.22%, 14 studies). Increased MDA concentrations in participants with malaria compared with uninfected controls were found in studies that enrolled patients with P. falciparum malaria (p < 0.01, Cohen d: 2.50, 95% CI: 1.90-3.10, I2: 89.7%, 7 studies) and P. vivax malaria (p < 0.01, Cohen d: 3.70, 95% CI: 2.48-4.92, I2: 90.11%, 3 studies). Our findings confirm that MDA concentrations increase during Plasmodium infection, indicating a rise in oxidative stress and lipid peroxidation. Thus, MDA levels can be a valuable biomarker for evaluating these processes in individuals with malaria. However, further research is necessary to fully elucidate the intricate relationship between malaria, antioxidants, oxidative stress, and the specific role of MDA in the progression of malaria.

Hepatic Anti-Oxidative Genes CAT and GPX4 Are Epigenetically Modulated by RORγ/NRF2 in Alphacoronavirus-Exposed Piglets

As a member of alpha-coronaviruses, PEDV could lead to severe diarrhea and dehydration in newborn piglets. Given that lipid peroxides in the liver are key mediators of cell proliferation and death, the role and regulation of endogenous lipid peroxide metabolism in response to coronavirus infection need to be illuminated. The enzymatic activities of SOD, CAT, mitochondrial complex-I, complex-III, and complex-V, along with the glutathione and ATP contents, were significantly decreased in the liver of PEDV piglets. In contrast, the lipid peroxidation biomarkers, malondialdehyde, and ROS were markedly elevated. Moreover, we found that the peroxisome metabolism was inhibited by the PEDV infection using transcriptome analysis. These down-regulated anti-oxidative genes, including GPX4, CAT, SOD1, SOD2, GCLC, and SLC7A11, were further validated by qRT-PCR and immunoblotting. Because the nuclear receptor RORγ-driven MVA pathway is critical for LPO, we provided new evidence that RORγ also controlled the genes CAT and GPX4 involved in peroxisome metabolism in the PEDV piglets. We found that RORγ directly binds to these two genes using ChIP-seq and ChIP-qPCR analysis, where PEDV strongly repressed the binding enrichments. The occupancies of histone active marks such as H3K9/27ac and H3K4me1/2, together with active co-factor p300 and polymerase II at the locus of CAT and GPX4, were significantly decreased. Importantly, PEDV infection disrupted the physical association between RORγ and NRF2, facilitating the down-regulation of the CAT and GPX4 genes at the transcriptional levels. RORγ is a potential factor in modulating the CAT and GPX4 gene expressions in the liver of PEDV piglets by interacting with NRF2 and histone modifications.

Potential Effects of High Temperature and Heat Wave on Nanorana pleskei Based on Transcriptomic Analysis

In the context of climate change, understanding how indigenous amphibians of the Qinghai-Tibet plateau react to stresses and their coping mechanisms could be crucial for predicting their fate and successful conservation. A liver transcriptome for Nanorana pleskei was constructed using high-throughput RNA sequencing, and its gene expression was compared with frogs acclimated under either room temperature or high temperature and also heat wave exposed ones. A total of 126,465 unigenes were produced, with 66,924 (52.92%) of them being annotated. Up to 694 genes were found to be differently regulated as a result of abnormal temperature acclimatization. Notably, genes belonging to the heat shock protein (HSP) family were down-regulated in both treated groups. Long-term exposure to high-temperature stress may impair the metabolic rate of the frog and trigger the body to maintain a hypometabolic state in an effort to survive challenging times. During heat waves, unlike the high-temperature group, mitochondrial function was not impaired, and the energy supply was largely normal to support the highly energy-consuming metabolic processes. Genes were more transcriptionally suppressed when treated with high temperatures than heat waves, and the body stayed in low-energy states for combating these long-term adverse environments to survive. It might be strategic to preserve initiation to executive protein activity under heat wave stress. Under both stress conditions, compromising the protection of HSP and sluggish steroid activity occurred in frogs. Frogs were more affected by high temperatures than by heat waves.

Dietary oxidized frying oil activates hepatic stellate cells and accelerates the severity of carbon tetrachloride- and thioacetamide-induced liver fibrosis in mice

Deep-frying is a common cooking practice worldwide, and after repeated heating's, the oil undergoes various chemical reactions, including hydrolysis, polymerization, lipid oxidation, and the Maillard reaction. Studies have pointed out that oxidized dietary frying oil may cause teratogenesis in mice and increase cancer and cardiovascular risks. The liver is the main organ involved in dietary nutrient catabolism, detoxification, bile production, and lipid metabolism. Nevertheless, the effects of oxidized frying oil exposure on the activation of hepatic stellate cells (HSCs) and liver fibrosis are still unclear. In this study, we showed that exposure to oxidized frying oil enhanced the sensitivity of HSCs to transforming growth factor (TGF)-β1-induced α-smooth muscle actin (α-SMA), collagen 1a2, collagen 1a1, metalloproteinase-2, and phosphorylated smad2/3 activation. In both carbon tetrachloride (CCl₄)- and thioacetamide (TAA)-induced liver fibrosis mouse models, we showed that long-term administration of a 10% fried oil-containing diet significantly upregulated fibrogenesis genes expression and deposition of hepatic collagen. Furthermore, long-term fried oil exposure not only promoted macrophage infiltration and increased inflammatory-related gene expression, but also accumulated excess cholesterol and lipid peroxidation in the liver tissues. In conclusion, our study demonstrated that feeding a fried oil-containing diet may trigger TGF-β1-induced HSCs activation and thereby promote liver damage and fibrosis progression through enhancing the inflammatory response and lipid peroxidation.

Role of Pyroptosis in Acetaminophen-Induced Hepatotoxicity

Acetaminophen (APAP) is a widely used pain reliever that can cause liver injury or liver failure in response to an overdose. Understanding the mechanisms of APAP-induced cell death is critical for identifying new therapeutic targets. In this respect it was hypothesized that hepatocytes die by oncotic necrosis, apoptosis, necroptosis, ferroptosis and more recently pyroptosis. The latter cell death is characterized by caspase-dependent gasdermin cleavage into a C-terminal and an N-terminal fragment, which forms pores in the plasma membrane. The gasdermin pores can release potassium, interleukin-1β (IL-1β), IL-18, and other small molecules in a sublytic phase, which can be the main function of the pores in certain cell types such as inflammatory cells. Alternatively, the process can progress to full lysis of the cell (pyroptosis) with extensive cell contents release. This review discusses the experimental evidence for the involvement of pyroptosis in APAP hepatotoxicity as well as the arguments against pyroptosis as a relevant mechanism of APAP-induced cell death in hepatocytes. Based on the critical evaluation of the currently available literature and understanding of the pathophysiology, it can be concluded that pyroptotic cell death is unlikely to be a relevant contributor to APAP-induced liver injury.

Ellagic acid attenuates beryllium sulphate-induced oxidative stress and histopathological alterations of spleen in rats

CONTEXT

Ellagic acid (EA) is a phenolic constituent in certain fruits and has largely been recognized for its role as an antioxidant compound.

OBJECTIVE

To evaluate the effect of EA on beryllium sulphate-induced splenic toxicity in rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into four groups. The first group was used as control. Group 2 was exposed to BeSO₄ (12 mg/kg, b.w.). Groups 3 and 4 were treated with EA (100 and 300 mg/kg, b.w.) daily for 6 weeks after exposing to BeSO₄ (12 mg/kg, b.w.). Various biochemical and molecular biomarkers were assessed in blood and spleen.

RESULTS

BeSO₄-intoxicated rats showed significant higher WBC (6.74 ± 0.20 × 10⁹/L vs. 11.02 ± 1.31 × 10⁹/L, p < 0.05), Neu (1.14 ± 0.11 × 10⁹/L vs. 2.45 ± 0.42 × 10⁹/L, p < 0.05), Lym (3.80 ± 0.83 × 10⁹/L vs. 9.64 ± 1.99 × 10⁹/L, p < 0.05), and PLT (868.4 ± 43.2 × 10⁹/L vs. 1408 ± 77.57 × 10⁹/L, p < 0.05) than normal control animals. Moreover, an increase in MDA with depletion of GSH and SOD activity (all p < 0.05) occurred in the spleen of rats treated with BeSO₄. Furthermore, BeSO₄-treated rats displayed significantly higher levels of apoptotic markers (Bax, Caspase-3, PARP) (all p < 0.05). EA administration resulted in a significant reversal of hematological and apoptotic markers in beryllium sulphate-intoxicated rats.

DISCUSSION AND CONCLUSIONS

Our results suggest EA treatment exerts a significant protective effect on BeSO₄-induced splenic toxicity in rats.

Ameliorative Effects of Oyster Protein Hydrolysates on Cadmium-Induced Hepatic Injury in Mice

Cadmium (Cd) is a widespread environmental toxicant that can cause severe hepatic injury. Oyster protein hydrolysates (OPs) have potential effects on preventing liver disease. In this study, thirty mice were randomly divided into five groups: the control, Cd, Cd + ethylenediaminetetraacetic acid (EDTA, 100 mg/kg), and low/high dose of OPs-treatment groups (100 mg/kg or 300 mg/kg). After continuous administration for 7 days, the ameliorative effect of OPs on Cd-induced acute hepatic injury in Cd-exposed mice was assessed. The results showed that OPs significantly improved the liver function profiles (serum ALT, AST, LDH, and ALP) in Cd-exposed mice. Histopathological analysis showed that OPs decreased apoptotic bodies, hemorrhage, lymphocyte accumulation, and inflammatory cell infiltration around central veins. OPs significantly retained the activities of SOD, CAT, and GSH-Px, and decreased the elevated hepatic MDA content in Cd-exposed mice. In addition, OPs exhibited a reductive effect on the inflammatory responses (IL-1β, IL-6, and TNF-α) and inhibitory effects on the expression of inflammation-related proteins (MIP-2 and COX-2) and the ERK/NF-κB signaling pathway. OPs suppressed the development of hepatocyte apoptosis (Bax, caspase-3, and Blc-2) and the activation of the PI3K/AKT signaling pathway in Cd-exposed mice. In conclusion, OPs ameliorated the Cd-induced hepatic injury by inhibiting oxidative damage and inflammatory responses, as well as the development of hepatocyte apoptosis via regulating the ERK/NF-κB and PI3K/AKT-related signaling pathways.

A toxicological evaluation for safety assessment of ruthenium-based diosmetin complex in rats

The flavonoid-based organometallic complexes have been identified as novel bioactive compounds with enhanced pharmacological and therapeutic activity. In this study, the ruthenium-p-cymene diosmetin complex was synthesized, characterized, and investigated for toxicological profiling through different toxicological and genotoxicological studies which include acute and sub-acute toxicity, chromosomal aberration, and bone marrow micronucleus study. The acute oral toxicity study demonstrated the LD₅₀ dose of the complex at 500 mg/kg body weight which further instigated the sub-acute doses i.e. 50, 100, and 200 mg/kg. The histopathological analysis demonstrated that the 400 mg/kg dose was associated with severe toxicological incidences of the vital organs (liver, kidney, pancreas, testis, and stomach) except the ovary with increased levels of ALP, AST, ALT, and WBC count. However, 50, 100, and 200 mg/kg doses did not show any toxicological alteration and maintained the normal levels of hematological and serum biochemical parameters. The genotoxicological assessment of the complex depicted no such genetic damage or mutagenicity in any complex treated groups. In conclusion, the 50, 100, and 200 mg/kg doses were determined as therapeutic dose of the novel ruthenium-p-cymene diosmetin complex without any genotoxic and mutagenic potential which can be further implemented in the investigation of various pharmacological and therapeutic interventions.

Transplantation of adipose-derived mesenchymal stem cells ameliorates acute hepatic injury caused by nonsteroidal anti-inflammatory drug diclofenac sodium in female rats

BACKGROUND

Although the beneficial role of adipose-derived mesenchymal stem cells (AD-MSCs) in acute liver injury has been addressed by numerous studies employing different liver injury inducers, the role of rat AD-MSCs (rAD-MSCs) in diclofenac sodium (DIC) - induced acute liver injury has not yet been clarified.

OBJECTIVE

This study aimed to investigate whether rat adipose- rAD-MSCs injected intraperitoneal could restore the DIC-induced hepatoxicity.

METHODS

Hepatotoxicity was induced by DIC in a dose-based manner, after which intraperitoneal injection of rAD-MSCs was performed.

RESULTS

Here, the transplanted cells migrated to the injured liver, and this was evidenced by detecting the specific SRY in the liver samples. After administering DIC, a significant decrease in body weight, survival rate, serum proteins, antioxidants, anti-apoptotic gene expression, and certain growth factors, whereas hepatic-specific markers, pro-inflammatory mediators, and oxidative, pro-apoptotic, and ER-stress markers were elevated. These adverse effects were significantly recovered after engraftment with rAD-MSCs. This was evidenced by enhanced survival and body weight, improved globulin and albumin values, increased expression of SOD, GPx, BCL-2, VEGF, and FGF-basic expression, and decreased serum ALT, AST, ALP, and total bilirubin. rAD-MSCs also reduced liver cell damage by suppressing the expression of MDA, IL-1B, IL-6, BAX, JNK, GRP78/BiP, CHOP, XBP-1, and cleaved caspase 3/7. Degenerative hepatic changes and multifocal areas of fatty change within liver cells were observed in DIC-received groups. These changes were improved with the transplantation of rAD-MSCs.

CONCLUSIONS

We could conclude that targeted AD-MSCs could be applied to reduce hepatic toxicity caused by NSAIDs (DIC).

Hepatoprotective effect of nanoniosome loaded Myristica fragrans phenolic compounds in mice-induced hepatotoxicity

In this study, nanoniosome‐loaded Myristica fragrans' (MF) phenolic compounds (NLMP) were synthesized and characterized for their physical properties, and hepatoprotective effects on mice with liver toxicity induced by L‐asparaginase (LA) injection. According to the results, NLMP has a spherical shape with a 263 nm diameter, a zeta potential of −26.55 mV and a polydispersity index (PDI) of 0.192. The weight and feed intake of mice induced with hepatotoxicity were significantly (p ≤ 0.05) increased after they were treated with NLMP (2.5 mg/kg body weight of mice). In addition, the blood levels of triglyceride (TG), cholesterol (Chol), liver enzymes (aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP)) and total bilirubin were significantly (p ≤ 0.05) decreased. A significant increase (p ≤ 0.05) in the blood levels of the antioxidant defence system (glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT)) were also reported after NLMP treatment. NLMP was also led to a significant decrease (p ≤ 0.05) in inflammatory‐related gene expression of inducible nitric oxide synthase (iNOS) and Interferon‐gamma (IFN‐γ) in the liver, as well as a meaningful (p ≤ 0.05) increase in the expression of SOD as an antioxidant status biomarker. Consequently, the NLMP is recommended as a potential dietary supplement to alleviate the symptoms of LA‐induced hepatotoxicity.

Oxidative Stress and Redox Signaling in the Pathophysiology of Liver Diseases

The increased production of derivatives of molecular oxygen and nitrogen in the form of reactive oxygen species (ROS) and reactive nitrogen species (RNS) lead to molecular damage called oxidative stress. Under normal physiological conditions, the ROS generation is tightly regulated in different cells and cellular compartments. Any disturbance in the balance between the cellular generation of ROS and antioxidant balance leads to oxidative stress. In this article, we discuss the sources of ROS (endogenous and exogenous) and antioxidant mechanisms. We also focus on the pathophysiological significance of oxidative stress in various cell types of the liver. Oxidative stress is implicated in the development and progression of various liver diseases. We narrate the master regulators of ROS-mediated signaling and their contribution to liver diseases. Nonalcoholic fatty liver diseases (NAFLD) are influenced by a "multiple parallel-hit model" in which oxidative stress plays a central role. We highlight the recent findings on the role of oxidative stress in the spectrum of NAFLD, including fibrosis and liver cancer. Finally, we provide a brief overview of oxidative stress biomarkers and their therapeutic applications in various liver-related disorders. Overall, the article sheds light on the significance of oxidative stress in the pathophysiology of the liver. © 2022 American Physiological Society. Compr Physiol 12:3167-3192, 2022.

Mitochondrial dysregulation occurs early in ALS motor cortex with TDP-43 pathology and suggests maintaining NAD+ balance as a therapeutic strategy

Mitochondrial defects result in dysregulation of metabolomics and energy homeostasis that are detected in upper motor neurons (UMNs) with TDP-43 pathology, a pathology that is predominantly present in both familial and sporadic cases of amyotrophic lateral sclerosis (ALS). While same mitochondrial problems are present in the UMNs of ALS patients with TDP-43 pathology and UMNs of TDP-43 mouse models, and since pathologies are shared at a cellular level, regardless of species, we first analyzed the metabolite profile of both healthy and diseased motor cortex to investigate whether metabolomic changes occur with respect to TDP-43 pathology. High-performance liquid chromatography, high-resolution mass spectrometry and tandem mass spectrometry (HPLC-MS/MS) for metabolite profiling began to suggest that reduced levels of NAD+ is one of the underlying causes of metabolomic problems. Since nicotinamide mononucleotide (NMN) was reported to restore NAD⁺ levels, we next investigated whether NMN treatment would improve the health of diseased corticospinal motor neurons (CSMN, a.k.a. UMN in mice). prpTDP-43^A315T-UeGFP mice, the CSMN reporter line with TDP-43 pathology, allowed cell-type specific responses of CSMN to NMN treatment to be assessed in vitro. Our results show that metabolomic defects occur early in ALS motor cortex and establishing NAD⁺ balance could offer therapeutic benefit to UMNs with TDP-43 pathology.

Bridelia ferruginea Benth. (Euphorbiaceae) mitigates oxidative imbalance and lipotoxicity, with concomitant modulation of insulin signaling pathways via GLUT4 upregulation in hepatic tissues of diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bridelia ferruginea Benth. (Euphorbiaceae) is among the medicinal plants commonly used for the management of type 2 diabetes (T2D) and its complications.

AIM OF THE STUDY

The hepato-therapeutic effect of the butanol fraction of Bridelia ferruginea leaves was investigated in diabetic rats.

METHODS

The butanol fraction of B. ferruginea was given to type 2 diabetic rats at both low and high doses (150 and 300 mg/kg bodyweight, respectively), while metformin and glibenclamide served as the standard anti-diabetic drugs. A normal toxicological group was administered a high dose of the fraction. At the end of the experimental period, the rats were sacrificed, and their livers and psoas muscle collected. The liver was assayed for oxidative stress markers, liver glycogen content, lipid metabolite profile (using GC-MS) and their metabolic pathways were analyzed using the MetaboAnalyst 5.0 online server. The expression of GLUT4 was also assayed in the liver and muscle as well as the identification of signaling pathways associated with GLUT4 expression using the Enrichr online server. In silico molecular docking was used to investigate the molecular interactions of some postulated compound found in B. ferruginea with GLUT4. The ability of the fraction to stimulate muscle glucose uptake was determined in isolated rat psoas muscle ex vivo.

RESULTS

Treatment with the high dose of fraction caused an inhibition of lipid peroxidation as well as the elevation of catalase, SOD, glutathione reductase and glutathione peroxidase activities in the rat liver. There was an increased expression of GLUT4 in livers and muscles of diabetic rats following treatment with B. ferruginea. Treatment with the fraction also caused inactivation of diabetes-activated pathways and changes in the distribution of the hepatic lipid metabolites. Molecular docking analysis revealed strong molecular interactions of pyrogallol and sitosterol with GLUT4.

CONCLUSIONS

These data illustrate the hepato-protective effect of B. ferruginea in diabetic rats which compare favorably with the tested anti-diabetic drugs (metformin and glibenclamide).

Can Erythropoietin Reduce Hypoxemic Neurological Damages in Neonates With Congenital Heart Defects?

Congenital heart defects (CHD), the most common cause of birth defects with increasing birth prevalence, affect nearly 1% of live births worldwide. Cyanotic CHD are characterized by hypoxemia, with subsequent reduced oxygen delivery to the brain, especially critical during brain development, beginning in the fetus and continuing through the neonatal period. Therefore, neonates with CHD carry a high risk for neurological comorbidities, even more frequently when there are associated underlying genetic disorders. We review the currently available knowledge on potential prevention strategies to reduce brain damage induced by hypoxemia during fetal development and immediately after birth, and the role of erythropoietin (EPO) as a potential adjunctive treatment. Maternal hyper-oxygenation had been studied as a potential therapeutic to improve fetal oxygenation. Despite demonstrating some effectiveness, maternal hyper-oxygenation has proven to be impractical for extensive clinical application, thus prompting the investigation of specific pathways for pharmacological intervention. Among those, the role of antioxidant pathways and Hypoxia Inducible Factors (HIF) have been studied for their involvement in the protective response to hypoxic injury. One of the proteins induced by HIF, EPO, has properties of being anti-apoptotic, antioxidant, and protective for neurons, astrocytes, and oligodendrocytes. In human trials, EPO administration in neonates with hypoxic ischemic encephalopathy (HIE) significantly reduced the neurological hypoxemic damages in several reported studies. Currently, it is unknown if the mechanisms of pathophysiology of cyanotic CHD are like HIE. Neonates with cyanotic CHD are exposed to both chronic hypoxemia and episodes of acute ischemia-reperfusion injury when undergo cardiopulmonary bypass surgery requiring aortic cross-clamp and general anesthesia. Our review supports future trials to evaluate the potential efficiency of EPO in reducing the hypoxemic neurologic damages in neonates with CHD. Furthermore, it suggests the need to identify early biomarkers of hypoxia-induced neurological damage, which must be sensitive to the neuroprotective effects of EPO.

Dietary polystyrene nanoplastics exposure alters liver lipid metabolism and muscle nutritional quality in carnivorous marine fish large yellow croaker (Larimichthys crocea)

Nanoplastics (NPs) cause various adverse effects on marine fish. However, effects of dietary NPs exposure on liver lipid metabolism and muscle nutritional quality of carnivorous marine fish are not fully understood. In this study, a 21-day feeding test was conducted to simulate the food chain transfer of polystyrene nanoplastics (PS NPs) and then evaluate effects of different dietary PS NPs levels on the survival, growth performance, liver lipid metabolism, and muscle nutritional quality of large yellow croaker Larimichthys crocea. Results indicated that the survival and growth of large yellow croaker decreased with the increase of PS NPs levels. Moreover, PS NPs induced excessive liver lipid accumulation by down-regulating the expression of lipolysis-related genes and inhibiting the AMPK-PPARα signaling pathway. In vitro, PS NPs could be accumulated in hepatocytes, reduce cell viability, and disrupt lipid metabolism of hepatocytes. Also, we found for the first time that PS NPs altered fatty acid composition and texture of fish muscle by enhancing oxidative stress and disrupting lipid metabolism. Overall, this study indicated that PS NPs induced liver lipid deposition by inhibiting lipolysis, and demonstrated that PS NPs altered the nutritional quality of fish, which might cause potential health effects for human consumers.

Comparative Analysis of the Antioxidative and Hepatoprotective Activities of Dimethyl Diphenyl Bicarboxylate in Four Animal Models of Hepatic Injury

As a well-known hepatoprotective and antioxidant agent, dimethyl diphenyl bicarboxylate (DDB) has frequently been employed to remedy various liver diseases. However, it is still uncertain whether DDB exerts consistent hepatoprotective and antioxidative activities against varying degrees of hepatic damage. Therefore, DDB (100, 25, 5, or 50 mg/kg depending on the model) was administered to animals in four representative models of liver injury (CCl₄ chemical acute model, DMN subchronic model, TAA chronic model, and restraint stress psychological acute model). Horizontal comparative analysis indicated that DDB significantly lowered the excess serum AST and ALT levels in the CCl₄ and DMN models but not in the TAA and restraint stress models. In accordance with this result, DDB markedly reduced oxidative stress indices (hepatic MDA and ROS) but restored five main antioxidant components (GSH content, GSH-peroxidase, GSH-reductase, SOD, and catalase activity) in the CCl₄ and DMN models. DDB failed to normalize oxidative stressors in the restraint stress-induced injury model and restore these five antioxidant components in the TAA model. Overall, our results produced a comprehensive overview of the effects of DDB on oxidative stressors and the main antioxidative components using four animal models. These findings will provide valuable clues to guide therapeutic clinical applications.

SERS diagnosis of liver fibrosis in the early stage based on gold nanostar liver targeting tags

In order to realize the accurate and early diagnosis of liver fibrosis, a long slow pathological process which may lead to cirrhosis or even liver cancer, liver targeting tags made up of gold nanostars and glycyrrhetinic acid are reported in this paper. Gold nanostars (GNSs) and GNS liver targeting tags (GLTTs) were injected into model mice with stage S1 liver fibrosis and normal mice via the tail vein respectively, then the SERS spectra were collected. GLTTs had a better detection effect on liver tissue than unmodified GNSs (12.85 times), and better detection reproducibility as well. Moreover, according to the MTT and survival analysis experiments, GLTTs also had better biocompatibility. Hence, the changes of 10 SERS signals and other substances in the early stage of liver fibrosis were analyzed at the molecular level, and the SERS characteristic peaks that could be used for the diagnosis of early liver fibrosis were screened out. Revealed by the experimental results, the GLTTs designed and prepared were applicable to the efficient SERS detection of early liver fibrosis in mice, and the strategy we have proposed might be a potential approach for the early diagnosis of this disease in clinics.

Edible Solanum trilobatum chloroform extract modulates CCL4 induced toxic changes in rat liver by enhancing the antioxidant activity

Liver diseases are one of the major causes of morbidity and mortality all over world. Environmental chemicals and pesticides are one of the most common causative factors for liver injury. Since there are no reliable hepatoprotective drugs available, many plant extracts are frequently utilized to treat liver disease. Therefore, searching for effective and safe plant based drugs for liver disorders is a matter of interest. In this study, hepatoprotective and antioxidant activity of the polyphenol rich chloroform extract of Solanum trilobatum (CST) was evaluated on CCl4 induced acute hepatotoxicity in Sprague Dawley rats. METHODS: Cytotoxic effect of CST on cancer cells as well as primary rat hepatocytes and proliferative effect on human peripheral blood lymphocyte (PBL) were evaluated in vitro. Animals were divided into 4 groups control group (received only normal saline), CCl4 group (received only CCl4 (2.0g/kg body weight), CST group (received 50 mg/kg and CCl4 (2.0g/kg body weight), CST group (received 100mg/kg and CCl4 (2.0g/kg body weight). After 14 consecutive days of treatment, the levels of hepatic biochemical markers, malondialdehyde (MDA) content, peroxidase and catalase activities were measured. The histopathological study of control and treated animals were also performed. RESULTS: Administration of CST prior to CCl4 was found to significantly inhibit the hepatotoxicity produced by CCl4 since CST restored the elevated activities of serum and liver marker enzymes and also enhanced the antioxidant enzyme levels. Histological changes caused by CCl4 were found to be significantly reversed by CST, which further confirms the dual effect of CST on CCl4-induced acute liver injury as a hepatoprotectant and antioxidant. CONCLUSIONS: The present study clearly demonstrates that CST contains therapeutic components which in combination/alone possess hepatoprotective and in vivo antioxidant effect.

Plasma membrane integrity: implications for health and disease

Plasma membrane integrity is essential for cellular homeostasis. In vivo, cells experience plasma membrane damage from a multitude of stressors in the extra- and intra-cellular environment. To avoid lethal consequences, cells are equipped with repair pathways to restore membrane integrity. Here, we assess plasma membrane damage and repair from a whole-body perspective. We highlight the role of tissue-specific stressors in health and disease and examine membrane repair pathways across diverse cell types. Furthermore, we outline the impact of genetic and environmental factors on plasma membrane integrity and how these contribute to disease pathogenesis in different tissues.

Superoxide Dismutase Administration: A Review of Proposed Human Uses

Superoxide dismutases (SODs) are metalloenzymes that play a major role in antioxidant defense against oxidative stress in the body. SOD supplementation may therefore trigger the endogenous antioxidant machinery for the neutralization of free-radical excess and be used in a variety of pathological settings. This paper aimed to provide an extensive review of the possible uses of SODs in a range of pathological settings, as well as describe the current pitfalls and the delivery strategies that are in development to solve bioavailability issues. We carried out a PubMed query, using the keywords "SOD", "SOD mimetics", "SOD supplementation", which included papers published in the English language, between 2012 and 2020, on the potential therapeutic applications of SODs, including detoxification strategies. As highlighted in this paper, it can be argued that the generic antioxidant effects of SODs are beneficial under all tested conditions, from ocular and cardiovascular diseases to neurodegenerative disorders and metabolic diseases, including diabetes and its complications and obesity. However, it must be underlined that clinical evidence for its efficacy is limited and consequently, this efficacy is currently far from being demonstrated.

Tioconazole and Chloroquine Act Synergistically to Combat Doxorubicin-Induced Toxicity via Inactivation of PI3K/AKT/mTOR Signaling Mediated ROS-Dependent Apoptosis and Autophagic Flux Inhibition in MCF-7 Breast Cancer Cells

Cancer is a complex devastating disease with enormous treatment challenges, including chemo- and radiotherapeutic resistance. Combination therapy demonstrated a promising strategy to target hard-to-treat cancers and sensitize cancer cells to conventional anti-cancer drugs such as doxorubicin. This study aimed to establish molecular profiling and therapeutic efficacy assessment of chloroquine and/or tioconazole (TIC) combination with doxorubicin (DOX) as anew combination model in MCF-7 breast cancer. The drugs are tested against apoptotic/autophagic pathways and related redox status. Molecular docking revealed that chloroquine (CQ) and TIC could be potential PI3K and ATG4B pathway inhibitors. Combination therapy significantly inhibited cancer cell viability, PI3K/AkT/mTOR pathway, and tumor-supporting autophagic flux, however, induced apoptotic pathways and altered nuclear genotoxic feature. Our data revealed that the combination cocktail therapy markedly inhibited tumor proliferation marker (KI-67) and cell growth, along with the accumulation of autophagosomes and elevation of LC3-II and p62 levels indicated autophagic flux blockage and increased apoptosis. Additionally, CQ and/or TIC combination therapy with DOX exerts its activity on the redox balance of cancer cells mediated ROS-dependent apoptosis induction achieved by GPX3 suppression. Besides, Autophagy inhibition causes moderately upregulation in ATGs 5,7 redundant proteins strengthened combinations induced apoptosis, whereas inhibition of PI3K/AKT/mTOR pathway with Beclin-1 upregulation leading to cytodestructive autophagy with overcome drug resistance effectively in curing cancer. Notably, the tumor growth inhibition and various antioxidant effects were observed in vivo. These results suggest CQ and/or TIC combination with DOX could act as effective cocktail therapy targeting autophagy and PI3K/AKT/mTOR pathways in MCF-7 breast cancer cells and hence, sensitizes cancer cells to doxorubicin treatment and combat its toxicity.

Govaniadine Ameliorates Oxidative Stress, Inflammation, and Kupffer Cell Activation in Carbon Tetrachloride-Induced Hepatotoxicity in Rats

Liver diseases such as hepatic carcinoma are one of the main health problems worldwide. Herbal drugs are largely used to treat liver injury in the indigenous system of medicine and may provide lead compounds for hepatoprotective drug discovery. The present study is investigated to test the Corydalis govaniana Wall. extract, fraction, and isolate therapeutically active constituents to explore their hepatoprotective, anti-inflammatory, and antioxidant activities. For this purpose, the antioxidant activity of govaniadine, caseadine, caseamine, and protopine was performed by assessing the scavenging events of the stable 2,2-diphenyl-1-picrylhydrazyl. Hepatoprotection of govaniadine was assessed in terms of reduction in serum enzymes (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) caused by CCl₄-induced liver injury in rats and by histopathological techniques. All the compounds showed significant antioxidant activity with a percentage inhibition of 92.2, 86.7, 85.3, and 79.7, respectively, compared to propyl gallate 90.3%. Treatment with govaniadine reduced the serum enzyme level down to normal levels in the CCl₄-treated group while inhibiting the increase of malondialdehyde, and the induction of superoxide dismutase and the glutathione level was upregulated. Histopathology showed ∼47% damage to the liver cells in the CCl₄-treated group; reduction in this damaged area was found to be better upon using govaniadine. Immunohistochemistry results showed that govaniadine as compared to silymarin has exceedingly decreased the inflammation by halting the CCl₄-induced activation of hepatic macrophages. In carrageenan-induced paw edema assay, govaniadine significantly alleviated the edema after 1-5 h at a dose of 20 mg/kg (26.00 and 28.5%), 50 mg/kg (22.05 and 27.0%), and 100 mg/kg (20.02 and 25.30%), respectively. The results of our experiments suggest that govaniadine showed antioxidant and hepatoprotective activity in liver injury. The hepatoprotective function of govaniadine may be associated to the scavenging of the free radical and attenuation of oxidative stress as well as inflammatory responses in the liver. Hence, govaniadine may be a lead compound for the hepatoprotective drug discovery process and further research is needed to find out their molecular mechanism of protection.

Role of cytoglobin, a novel radical scavenger, in stellate cell activation and hepatic fibrosis

Cytoglobin (Cygb), a stellate cell-specific globin, has recently drawn attention due to its association with liver fibrosis. In the livers of both humans and rodents, Cygb is expressed only in stellate cells and can be utilized as a marker to distinguish stellate cells from hepatic fibroblast-derived myofibroblasts. Loss of Cygb accelerates liver fibrosis and cancer development in mouse models of chronic liver injury including diethylnitrosamine-induced hepatocellular carcinoma, bile duct ligation-induced cholestasis, thioacetamide-induced hepatic fibrosis, and choline-deficient L-amino acid-defined diet-induced non-alcoholic steatohepatitis. This review focuses on the history of research into the role of reactive oxygen species and nitrogen species in liver fibrosis and discusses the current perception of Cygb as a novel radical scavenger with an emphasis on its role in hepatic stellate cell activation and fibrosis.

Investigation of benfotiamine’s protective effects on liver tissue in experimental carbon tetrachloride induced liver injury

Purpose: In this study, we aimed to investigate the protective effects of benfotiamine on experimental liver injury caused by carbon tetrachloride (CCl4).Materials and Methods: In this study, 30 male Wistar albino rats were used. Rats were equally divided into 5 groups. No application was made to control group. The CCl4 group was injected i.p with1ml/kg CCl4:olive oil (1:2) mixture on the 1st and 8th days, and the CCl4+benfotiamine group was treated i.p with 1 ml/kg CCl4: olive oil (1:2) mixture twice on the 1st and 8th days and orally with 70 mg/kg/day benfotiamine. To the benfotiamine group, 70 mg/kg/day benfotiamine was given orally for 14 days. To the olive oil group, 2 ml/kg olive oil was given i.p. on 1st and 8th days. Finally, rats were decapitated. Liver tissues were removed and paraffin blocks were prepared. Tissues were stored at –80 oC for malonaldeyhde (MDA) assay.Results: There were no significant differences between the control, benfotiamine and olive oil groups. Compared with the control group, there was a significant increase in MDA, apoptosis and bax immunoreactivity in CCl4 group. Compared with the CCl4 group, there was a significant decrease in MDA, apoptosis and bax immunoreactivity in the CCl4+benfotiamine group.Conclusion: CCl4 increases MDA, apoptosis and bax immunoreactivity, and benfotiamine, given as treatment, reduces these parameters. 

Herbal syrup from chicory and artichoke leaves ameliorate liver damage induced by deltamethrin in weanling male rats

Pyrethroid insecticides are extensively used for control insects in both public health and agriculture sectors. Despite the important role of these insecticides, it caused adverse toxic effects on human, especially at the weanling stage. In this work, the antioxidant activity of chicory and artichoke leaves extracts, and phenolic flavonoid contents were studied. In addition, herbal syrup formulation and hepatoprotective effect against oxidative stress, lipid peroxidation, and liver damage induced by deltamethrin in weanling male rats were investigated. Both extracts have high phenolic, flavonoid contents, and antioxidant activity. Deltamethrin reduced body and liver weights of weanling rats. It induced oxidative stress, lipid peroxidation, and altered liver function enzymes. It caused a histopathological alteration in liver tissue. Supplementation of herbal syrup improved the above changes via increase body weights, antioxidant enzymes, and decrease lipid peroxidation, and enhanced histopathological profile. It can be concluded that herbal syrup of chicory and artichoke leaves extracts can ameliorate liver damage induced by deltamethrin. Herbal syrup from agriculture wastes of chicory and artichoke leaves is considered an easy, economical, and useful formulation for protecting agriculture workers against the adverse effects induced by pyrethroid insecticides especially in poor rural in developing countries where pyrethroid insecticides are applied for control vector-borne diseases and insects in agriculture.

Camellia Oleifera Seed Extract Mildly Ameliorates Carbon Tetrachloride-Induced Hepatotoxicity in Rats by Suppressing Inflammation

The objective of this study was to evaluate the effects of a hot-water extract of defatted Camellia oleifera seeds (CSE) in carbon tetrachloride (CCl₄ )-induced liver damage in rats. Wistar rats were separated into four groups including the normal (N) and CCl₄ control (C) groups, which are fed a control diet, and the CCL (low-dose CSE) and CCH (high-dose CSE) groups, which are fed with a control diet plus different amount of CSE for an 8-week experimental period. Liver injury in the C, CCL, and CCH groups was induced by injecting CCl₄ (i.p.) twice a week from the 5th week to the end of the study. In CCl₄ -treated rats, the alanine transaminase (ALT) and aspartate transaminase (AST) activities and malondialdehyde (MDA) concentration significantly increased compared to the normal group. Lower antioxidative enzyme activities and higher proinflammatory cytokines, transforming growth factor-β (TGF-β) and hydroxyproline concentrations in the liver were also found in the CCl₄ -treated group compared to the normal group. In contrast, the administration of CSE alleviated the biochemical and histopathological changes including inflammation, liver cell damage, and fibrosis caused by CCl₄ in rats. Our results indicated that CSE exhibited hepatoprotective effects in CCl₄ -induced liver hepatotoxicity through alleviating hepatic inflammation and fibrosis in rats. PRACTICAL APPLICATION: Camellia oleifera are widely used for edible oil production while the defatted seeds pomace is often discarded. We found that extract of C. oleifera pomace containing phenolic compounds, saponins, and polysaccharides showed protective effects chemical-driven liver damage and, therefore, may be used in further studies and developing functional foods.

Protective effect of essential oil of Cinnamomum verum bark on hepatic and renal toxicity induced by carbon tetrachloride in rats

The inner bark of cinnamon (Cinnamomum verum) is widely used as a spice. Cinnamon plants are also a valuable source of essential oil used for medicinal purposes. The present study aimed to investigate the composition and in vitro antioxidant activity of essential oil of C. verum bark (CvEO) and its protective effects in vivo on CCl₄-induced hepatic and renal toxicity in rats. Groups of animals were pretreated for 7 days with CvEO (70 or 100 mg/kg body weight) or received no treatment and on day 7 a single dose of CCl₄ was used to induce oxidative stress. Twenty-four hours after CCl₄ administration, the animals were euthanized. In the untreated group, CCl₄ induced an increase in serum biochemical parameters and triggered oxidative stress in both liver and kidneys. CvEO (100 mg/kg) caused significant reductions in CCl₄-elevated levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, γ-glutamyl transferase, lactate dehydrogenase, total cholesterol, triglycerides, low-density lipoprotein, urea, and creatinine and increased the level of high-density lipoprotein compared with the untreated group. Moreover, pretreatment with CvEO at doses of 70 and 100 mg/kg before administration of CCl₄ produced significant reductions in thiobarbituric acid reactive substances and protein carbonyl levels in liver and kidney tissues compared with the untreated group. The formation of pathological hepatic and kidney lesions induced by the administration of CCl₄ was strongly prevented by CvEO at a dose of 100 mg/kg. Overall, this study suggests that administration of CvEO has high potential to quench free radicals and alleviate CCl₄-induced hepatorenal toxicity in rats.

Computational Modeling of Oxidative Stress in Fatty Livers Elucidates the Underlying Mechanism of the Increased Susceptibility to Ischemia/Reperfusion Injury

QUESTION

Donor liver organs with moderate to high fat content (i.e. steatosis) suffer from an enhanced susceptibility to ischemia/reperfusion injury (IRI) during liver transplantation. Responsible for the cellular injury is an increased level of oxidative stress, however the underlying mechanistic network is still not fully understood.

METHOD

We developed a phenomenological mathematical model of key processes of hepatic lipid metabolism linked to pathways of oxidative stress. The model allows the simulation of hypoxia (i.e. ischemia-like conditions) and reoxygenation (i.e. reperfusion-like conditions) for various degrees of steatosis and predicts the level of hepatic lipid peroxidation (LPO) as a marker of cell damage caused by oxidative stress.

RESULTS & CONCLUSIONS

Our modeling results show that the underlying feedback loop between the formation of reactive oxygen species (ROS) and LPO leads to bistable systems behavior. Here, the first stable state corresponds to a low basal level of ROS production. The system is directed to this state for healthy, non-steatotic livers. The second stable state corresponds to a high level of oxidative stress with an enhanced formation of ROS and LPO. This state is reached, if steatotic livers with a high fat content undergo a hypoxic phase. Theoretically, our proposed mechanistic network would support the prediction of the maximal tolerable ischemia time for steatotic livers: Exceeding this limit during the transplantation process would lead to severe IRI and a considerable increased risk for liver failure.

Modulation of the Oxidative Stress and Lipid Peroxidation by Endocannabinoids and Their Lipid Analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts.

An ellagic acid isolated from Clerodendrum viscosum leaves ameliorates iron-overload induced hepatotoxicity in Swiss albino mice through inhibition of oxidative stress and the apoptotic pathway

Iron is a vital element required for normal cellular physiology in animal systems, but excess iron accumulation in the biological system accelerates oxidative stress, cellular toxicity, tissue injury and organ fibrosis, which ultimately leads to the generation of chronic liver diseases including cancer. A natural antioxidant, ellagic acid (EA) has been previously reported for its pharmacological properties; however, there is no significant evidence available that could illustrate its protective potential against iron-overload induced hepatotoxicity. In the present work, EA was evaluated for its in vitro free radical scavenging and iron chelation potentials. Further, EA was tested in vivo for its protective activity against iron overload-induced hepatotoxicity in Swiss albino mice by evaluating liver iron content, reactive oxygen species (ROS), liver antioxidant enzymes, serum marker levels, liver damage and fibrosis, histopathological study and finally western blotting analysis. EA treatment significantly decreased liver iron and serum ferritin levels. Elevated ROS levels, decreased antioxidant parameters and elevated serum markers were normalized upon treatment with EA. Cellular morphology, iron -overload and liver fibrosis were found to be effectively ameliorated. Finally, the protective effect of EA against iron overload-induced apoptosis was confirmed by western blotting when its treatment upregulated the expressions of caspase-3 and poly(ADP-ribose) polymerase (PARP) proteins. EA revealed hepatoprotective activity against iron overload-induced toxicity through scavenging free radicals, inhibiting excess ROS production, normalizing liver damage parameters and upregulating caspase-3, PARP expression. Collectively, our findings support the possible use of the natural antioxidant EA as a promising candidate against iron-overloaded diseases.

A natural antioxidant, tannic acid mitigates iron-overload induced hepatotoxicity in Swiss albino mice through ROS regulation

Tannic acid (TA), a water soluble natural polyphenol with 8 gallic acids groups, is abundantly present in various medicinal plants. Previously TA has been investigated for its antimicrobial and antifungal properties. Being a large polyphenol, TA chelates more than 1 metal. Hence TA has been explored for potent antioxidant activities against reactive oxygen species (ROS), reactive nitrogen species (RNS) and as iron chelator in vitro thereby mitigating iron-overload induced hepatotoxicity in vivo. Iron dextran was injected intraperitoneally in Swiss albino mice to induce iron-overload triggered hepatotoxicity, followed by oral administration of TA for remediation. After treatment, liver, spleen, and blood samples were processed from sacrificed animals. The liver iron, serum ferritin, serum markers, ROS, liver antioxidant status, and liver damage parameters were assessed, followed by histopathology and protein expression studies. Our results show that TA is a prominent ROS and RNS scavenger as well as iron chelator in vitro. It also reversed the ROS levels in vivo and restricted the liver damage parameters as compared to the standard drug, desirox. Moreover, this natural polyphenol exclusively ameliorates the histopathological and fibrotic changes in liver sections reducing the iron-overload, along with chelation of liver iron and normalization of serum ferritin. The protective role of TA against iron-overload induced apoptosis in liver was further supported by changed levels of caspase 3, PARP as well as Bax/BCl-2 ratio. Thus, TA can be envisaged as a better orally administrable iron chelator to reduce iron-overload induced hepatotoxicity through ROS regulation.

Lipid Peroxidation and Cancer: A Critical Reconsideration

The author reviews the problem of the pattern of lipid peroxidation in cancer cells with special reference to a comparison between normal liver cells and hepatomas both transplanted and induced by diethylnitrosamine. It is stated that the loss of lipid peroxidation is proportional to the degree of dedifferentiation of hepatoma cells. During carcinogenesis, however, the loss is already evident at the stage of preneoplastic nodules. A common feature of all tumors, independently of the extent of the loss of peroxidation in basal conditions, is the lack of further stimulation by ADP/iron or by ascorbate/iron. As regards the reasons for the decline in lipid peroxidation, they are certainly not unique. An important cause is the low activity of the enzymes of the monooxygenase microsomal chain. Another very important one is the change in lipid composition of membranes, with a marked decrease in polyunsaturated fatty acids, which are the main substrate for lipid peroxidation. It has been shown that enrichment of membranes of hepatomas with arachidonic acid results in restoration of stimulation of peroxidation by ascorbate/iron, but not with ADP/iron. The last type of stimulation mostly reflects the behaviour of the monooxygenase chain, whereas ascorbate/ iron-induced stimulation does not require the presence of an efficient cytochrome P450-chain. Another cause for decreased lipid peroxidation in tumors is the increased rigidity of membranes, due to the large increase in cholesterol content: this prevents to some extent the influx of oxygen inside the membranes. Yet another cause is the presence of increased amounts of antioxidants in both cytosol and membranes. The main toxic product of lipid peroxidation, 4-hydroxynonenal, has been found to elicit several actions at extremely low concentrations. In fact, 4-hydroxynonenal stimulates Chemotaxis of polymorphonuclear leukocytes, stimulates plasma membrane adenylate cyclase, stimulates plasma membrane guanylate cyclase, and stimulates phospholipase C. The last three enzymes involve the action of G-proteins. The effect of the aldehyde is present at less than micromolar concentrations, which may occur inside the cells in certain conditions. Morever, at concentrations from 10–6 to 10–7 M, the aldehyde is able to block oncogene c-myc expression in the human erythroleukemic K562 cell line, which at the same time becomes able to express the gamma-globin gene. These facts are discussed with reference to a possible biological meaning of the loss of lipid peroxidation in tumors.

Oxidative Stress and Acute Hepatic Injury

Reactive oxygen species have long been implicated in the pathophysiology of acute liver injury. However, the translation of these findings to the clinic and the development of therapeutic agents have been slow mainly due to the poor mechanistic understanding of the pathophysiology and the many indirect approaches used to characterize the role of oxidant stress in liver injury. The current review discusses in depth the sources of reactive oxygen, the oxidants involved and the impact of this oxidant stress in the mechanism of cell death in 3 different clinically relevant acute liver injury models.

Sildenafil, a phosphodiesterase-5 inhibitor, offers protection against carbon tetrachloride-induced hepatotoxicity in rat

BACKGROUND

Elevation of phosphodiesterase-5 (PDE5) activity converts cyclic guanosine monophosphate (cGMP) to 5'-GMP, a mechanism that could be associated with drug-mediated hepatotoxicity. This study investigated whether selective inhibition of PDE5 by sildenafil could offer protection against hepatotoxicity induced by carbon tetrachloride (CCl4).

METHODS

CCl4 (0.5 mL/kg) was administered intraperitoneally to induce hepatotoxicity. The control group received normal saline. Sildenafil (5 mg, 10 mg, and 20 mg/kg, p.o.) was administered to CCl4-treated rats.

RESULTS

CCl4 significantly increased the serum levels of gamma glutamyl transferase (γ-GT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) and reduced total protein (TP) (p<0.05). Pretreatment with sildenafil moderately reduced ALP, AST, and ALT activities with modest increase in TP level. CCl4-induced changes in the antioxidant status of the liver were significantly improved by sildenafil, especially at the lowest dose of 5 mg/kg by elevating the levels of reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) and preventing lipid peroxidation (p<0.05). Sildenafil did not significantly alter the total cholesterol and triglyceride levels. However, high-density lipoprotein (HDL) level was significantly increased by sildenafil (p<0.05).

CONCLUSIONS

The results from this study suggest that sildenafil, when used at low doses, may be a useful pharmacological protective agent against CCl4-induced hepatotoxicity.

Hepatoprotective effect of methanolic Tanacetum parthenium extract on CCl4-induced liver damage in rats

The purpose of this study was to investigate the effects of Tanacetum Parthenium Extract (TPE) on Lipid peroxidation, antioxidant enzymes, biochemical factors, and liver enzymes in the rats damaged by Carbon Tetrachloride (CCl4). 54 male Wistar rats were divided into 9 groups each consisting of 6 rats. Two of the groups were control groups (normal and damage control groups), 4 of them were exposure groups which were respectively administered with 40, 80, and 120 mg/kg of TPE and silymarin for 14 days before being damaged by CCl4, and the other 3 groups were post-treatment groups which received 80 and 120 mg/kg of TPE and silymarin 2, 6, 24, and 48 h after being injected with CCl4. At the end of the study, biochemical factors, serum liver enzymes, malondialdehyde level, antioxidant enzymes, and liver morphology were assayed. Pre- and post-treatment with TPE could significantly decrease ALT, AST, ALP, TG, LDL, TC, and glucose levels and increase HDL, and albumin levels and catalase, SOD, and GPx activities compared to the CCl4-damaged control group. The results of this study are indicative of the antioxidant activity of TPE, its potential hepatoprotective effects, and its probable therapeutic properties for laboratory animals damaged by CCl4.

Deep fried edible oils disturb hepatic redox equilibrium and heightens lipotoxicity and hepatosteatosis in male Wistar rats

Hepatosteatosis is a complex disorder, in which insulin resistance and associated dyslipidemic and inflammatory conditions are fundamental. Dietary habit, especially regular consumption of fat and sugar-rich diet, is an important risk factor. Coconut and mustard oils (CO and MO) are medium-chain saturated and monounsaturated fats that are common dietary ingredients among the Indian populations. Present study analyzed the effect of prolonged consumption of the fresh and thermally oxidized forms of these oils on glucose tolerance and hepatosteatosis in male Wistar rats. Thermally oxidized CO (TCO) and MO (TMO) possessed higher amount of lipid peroxidation products and elevated p-anisidine values than their fresh forms. Dietary administration of TCO and TMO along with fructose altered glucose tolerance and increased hyperglycemia in rats. Dyslipidemia was evident by elevated levels of triglycerides and reduced high density lipoprotein cholesterol (HDLc) levels in fructose and edible oil-fed group ( p < 0.05). Additionally, hepatic antioxidant status was diminished and oxidative stress markers were elevated in TCO- and TMO-fed rats. Substantiating these, hike in liver function marker enzyme activities were also observed in these animals. Supporting this, histological analysis revealed higher incidence of microvesicles and hepatocellular ballooning. Results thus suggest that consumption of thermally oxidized fats may cause hepatic damage.

Influence of coumarin and some coumarin derivatives on serum lipid profiles in carbontetrachloride-exposed rats

In the present study, coumarin and some coumarin derivatives (esculetin, scoparone, and 4-methylumbelliferone) were investigated for their lipid-lowering effect in rats. Male Sprague–Dawley rats (150–200 g) were divided into six groups and each group comprised of five rats. Hepatic injury-dependent hyperlipidemia was induced by carbon tetrachloride (CCl4, 1.25 ml/kg). Coumarin and coumarin derivatives esculetin (35 mg/kg), scoparone (35 mg/kg), 4-methylumbelliferone (35 mg/kg), or coumarin (30 mg/kg) were administered to experimental groups at 12-h intervals. Animals received the derivatives esculetin, scoparone or 4-methylumbelliferone prior to the administration of a single toxic dose of CCl4. Serum total cholesterol (TC), triglyceride (TG), very low-density lipoprotein cholesterol (VLDL-C), and low-density lipoprotein cholesterol (LDL-C) levels significantly increased in CCl4-treated group ( p < 0.05, p < 0.01, p < 0.01, and p < 0.05, respectively), while levels of serum high-density lipoprotein cholesterol (HDL-C) decreased ( p < 0.01). 4-Methylumbelliferone had no recovery effects on serum TC levels, however, significantly prevented CCl4-induced hyperlipidemia by reducing TG and VLDL-C levels ( p < 0.05 and p < 0.05, respectively). In addition, coumarin had no recovery effect on any of the serum lipid parameters against CCl4-induced hyperlipidemia. Among the coumarin derivatives only esculetin and scoparone significantly prevented serum HDL-C in CCl4-induced dyslipidemia. The results from this study indicate that the chemical structure of coumarins plays an important role on the regulation of serum lipid profiles.

Extraction, identification, fractionation and isolation of phenolic compounds in plants with hepatoprotective effects

The liver is one of the most important organs of human body, being involved in several vital functions and regulation of physiological processes. Given its pivotal role in the excretion of waste metabolites and drugs detoxification, the liver is often subjected to oxidative stress that leads to lipid peroxidation and severe cellular damage. The conventional treatments of liver diseases such as cirrhosis, fatty liver and chronic hepatitis are frequently inadequate due to side effects caused by hepatotoxic chemical drugs. To overcome this problematic paradox, medicinal plants, owing to their natural richness in phenolic compounds, have been intensively exploited concerning their extracts and fraction composition in order to find bioactive compounds that could be isolated and applied in the treatment of liver ailments. The present review aimed to collect the main results of recent studies carried out in this field and systematize the information for a better understanding of the hepatoprotective capacity of medicinal plants in in vitro and in vivo systems. Generally, the assessed plant extracts revealed good hepatoprotective properties, justifying the fractionation and further isolation of phenolic compounds from different parts of the plant. Twenty-five phenolic compounds, including flavonoids, lignan compounds, phenolic acids and other phenolic compounds, have been isolated and identified, and proved to be effective in the prevention and/or treatment of chemically induced liver damage. In this perspective, the use of medicinal plant extracts, fractions and phenolic compounds seems to be a promising strategy to avoid side effects caused by hepatotoxic chemicals.