Modulation of keap-1/Nrf2/HO-1 and NF-ĸb/caspase-3 signaling pathways by dihydromyricetin ameliorates sodium valproate-induced liver injury.

Nuclear factor erythroid factor 2 (Nrf2) is the key regulatory of the antioxidant response elements. Also, Nrf2 interacts with nuclear factor kappa B (NF-ĸB) to inhibit subsequent inflammatory cascade. Activation of Nrf2 signaling ameliorates drug-induced liver injury. Sodium valproate (SVP) is an anti-epilepsy drug with a hepatotoxic adverse effect that restricts its clinical use. In this study, coadministration of Dihydromyricetin (DHM), a natural flavonoid, with SVP to rats upregulated gene expression of Nrf2 and its downstream gene, heme oxygenase 1 (HO-1), while suppressed the Nrf2 repressor, Keap-1. Additionally, DHM led to downregulation of proinflammatory factors in liver tissues, including NF-ĸB, interleukin 1 beta (IL-1ß), and tumor necrosis factor alpha (TNF-α). This was accompanied by a decrease in the proapoptotic protein (cleaved caspase-3) expression level. Furthermore, biochemical and histopathological studies showed that DHM treatment improved liver function and lipid profile while decreased inflammatory cell infiltration, congestion, and hepatocellular damage. According to our knowledge, prior research has not examined the protective effect of DHM on the liver injury induced by SVP. Consequently, this study provides DHM as a promising herbal medication that, when used with SVP, can prevent its induced hepatotoxicity owing to its potential anti-oxidative, anti-inflammatory, and anti-apoptotic properties.

Downregulation of IL-1ß/p38 mitogen activated protein kinase pathway by diacerein protects against kidney ischemia/reperfusion injury in rats.

Renal ischemia-reperfusion (I/R) can be precipitated by multiple clinical situations that lead to impaired renal function and associated mortality. The resulting tubular cell damage is the outcome of complex disorders including, an inflammatory process with an overproduction of cytokines. Here, diacerein (DIA), an inhibitor of proinflammatory cytokine interleukin-1 beta (IL-1ß), was investigated against renal I/R in rats. DIA was orally administrated (50 mg/kg/day) for ten days before bilateral ischemia for 45 min with subsequent 2 hr. reperfusion. Interestingly, DIA alleviated the renal dysfunction and histopathological damage in the renal tissues. Pretreatment with DIA corrected the oxidative imbalance by prevented reduction in antioxidant levels of GSH and SOD, while it decreased the elevation of the oxidative marker, MDA. In addition, DIA downregulated IL-1ß and TNF-α expression in the renal tissues. Consequent to inhibition of the oxidative stress and inflammatory cascades, DIA inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Therefore, downstream targets for p38 MAPK were also inhibited via DIA which prevented further increases of inflammatory cytokines and the apoptotic marker, caspase-3. Collectively, this study revealed the renoprotective role of DIA for renal I/R and highlighted the role of p38 MAPK encountered in its therapeutic application in renal disease.

Blackberry-Loaded AgNPs Attenuate Hepatic Ischemia/Reperfusion Injury via PI3K/Akt/mTOR Pathway.

Liver ischemia-reperfusion injury (IRI) is a pathophysiological insult that often occurs during liver surgery. Blackberry leaves are known for their anti-inflammatory and antioxidant activities. AIMS: To achieve site-specific delivery of blackberry leaves extract (BBE) loaded AgNPs to the hepatocyte in IRI and to verify possible molecular mechanisms. METHODS: IRI was induced in male Wister rats. Liver injury, hepatic histology, oxidative stress markers, hepatic expression of apoptosis-related proteins were evaluated. Non-targeted metabolomics for chemical characterization of blackberry leaves extract was performed. KEY FINDINGS: Pre-treatment with BBE protected against the deterioration caused by I/R, depicted by a significant improvement of liver functions and structure, as well as reduction of oxidative stress with a concomitant increase in antioxidants. Additionally, BBE promoted phosphorylation of antiapoptotic proteins; PI3K, Akt and mTOR, while apoptotic proteins; Bax, Casp-9 and cleaved Casp-3 expressions were decreased. LC-HRMS-based metabolomics identified a range of metabolites, mainly flavonoids and anthocyanins. Upon comprehensive virtual screening and molecular dynamics simulation, the major annotated anthocyanins, cyanidin and pelargonidin glucosides, were suggested to act as PLA2 inhibitors. SIGNIFICANCE: BBE can ameliorate hepatic IRI augmented by BBE-AgNPs nano-formulation via suppressing, oxidative stress and apoptosis as well as stimulation of PI3K/Akt/mTOR signaling pathway.

Agomelatine ameliorates cadmium-induced toxicity through the modification of HMGB-1/TLR-4/NFκB pathway.

Cadmium (Cd) has potential hazards on human beings. Consequently, this study was performed to explore the protective effects of agomelatine (AGO), a melatonin receptor agonist, against Cd-induced toxicity in rats. AGO (40 mg/kg/day) was administered orally concomitant with intra peritoneal injection of Cd (0.4 mg/kg/day) for 14 days. Then, blood, biochemical parameters and histological examination of affected organs including, heart and testis, were evaluated. Interestingly, AGO significantly counteracted Cd-induced elevation of serum cardiac enzymes. Similarly, AGO significantly improved the deterioration of serum testosterone level with Cd administration. The oxidative balance was corrected by AGO, as evidenced by decrease malondialdehyde (MDA), and superoxide dismutase activity in cardiac and testicular tissues. Additionally, AGO increased silent information regulator 1 protein (SIRT-1) and decreased High mobility group box 1 (HMGB1), Toll like receptor-4 (TLR-4), and Myd88 levels that subsequently reduced expression of nuclear factor-κB (NF-κB). Moreover, level of apoptotic marker; caspase-3 was inhibited by AGO. In accordance with the biochemical and molecular results, AGO restored structure of cardiac myofibers and seminiferous tubules. Collectively, AGO mitigated cardiac and testicular toxicity of Cd via modulation of SIRT-1/HMGB1 and its downstream pathway.

Cichoriin, a Biocoumarin, Mitigates Oxidative Stress and Associated Adverse Dysfunctions on High-Fat Diet-Induced Obesity in Rats.

Metabolic dysfunctions linked to obesity carry the risk of co-morbidities such as diabetes, hepatorenal, and cardiovascular diseases. Coumarins are believed to display several biological effects on diverse adverse health conditions. This study was conducted to uncover the impact of cichoriin on high-fat diet (HFD)-induced obese rats. Methods: Obesity was induced in twenty rats by exposure to an HFD for six weeks. The rats were randomly divided into five groups; group I comprised five healthy rats and was considered the control one. On the other hand, the HFD-induced rats were divided into the following (five per each group): group II (the HFD group), groups III (cichoriin 50 mg/kg) and IV (cichoriin 100 mg/kg) as the treatment groups, and group V received atorvastatin (10 mg/kg) (as a standard). Triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT), aspartate transaminase (AST), creatine kinase MB (CK-MB), urea, creatinine, the hepatic and renal malondialdehyde (MDA) as well as reduced glutathione (GSH) levels were assessed. Histopathological analysis of the heart, kidney, and liver tissues was investigated. mRNA and protein expressions of the peroxisome proliferator-activated receptor gamma (PPAR-γ) were estimated. Results: The administration of cichoriin alleviated HFD-induced metabolic dysfunctions and improved the histopathological characteristics of the heart, kidney, and liver. Additionally, the treatment improved the lipid profile and hepatic and renal functions, as well as the oxidative balance state. Cichoriin demonstrated an upregulation of the mRNA and protein expressions of PPAR-γ. Taken together, these findings are the first report on the beneficial role of cichoriin in alleviating adverse metabolic effects in HFD-induced obesity and adapting it into an innovative obesity management strategy.

Mechanistic Insights into the Ameliorative Effect of Cichoriin on Diabetic Rats-Assisted with an In Silico Approach.

Type 2 diabetes mellitus is considered to be a substantial socioeconomic burden worldwide on both patients and governments. Coumarins are biomolecules with a diversity of biological activities. The current investigation aimed to explore the ameliorative effects of cichoriin, which is a type of coumarin, on high-fat diet/streptozotocin (HFD/STZ)-induced diabetic rats. METHODS: Rats were allocated into five groups. Group I was considered as the control group, while the other groups were HFD/STZ-induced diabetic rats. Group II was assigned as the diabetic control. Groups III and IV were treated with cichoriin (50 or 100 mg/kg, respectively). Group V received glibenclamide (5 mg/kg) (as a positive control). The blood glucose (BG), serum insulin, triglycerides (TG), total cholesterol (TC), total antioxidant capacity (TAC), catalase, hepatic superoxide dismutase (SOD) and content of malondialdehyde (MDA) were assessed. Histopathological and immunohistochemistry analysis of pancreatic tissue were performed. mRNA and protein expressions of GLUT4, AMPK, and PI3K were estimated. RESULTS: Cichoriin treatment ameliorated HFD/STZ-induced diabetic conditions and mitigated the histopathological characteristics of the pancreas, as well as increasing pancreatic insulin expression. This decreased the levels of BG, TG, TC, and MDA and improved the TAC, catalase and SOD contents. Cichoriin demonstrated upregulation of mRNA and protein expressions of GLUT4, AMPK, and PI3K. The in silico binding of cichoriin with GLUT4, AMPK, and PI3K supported the possible current activities. CONCLUSION: Collectively, this work highlighted the potential role of cichoriin in mitigating HFD/STZ-induced diabetic conditions and showed it to be a valuable product.

Dihydromyricetin alleviates methotrexate-induced hepatotoxicity via suppressing the TLR4/NF-κB pathway and NLRP3 inflammasome/caspase 1 axis.

The anticancer drug methotrexate (MTX) is known to cause hepatotoxicity as a possibly fatal adverse effect that hinders its clinical application. Although the natural flavonoid, dihydromyricetin (DHM), has antioxidant and anti-inflammatory effects; its role against MTX-induced hepatotoxicity has not been explored yet. For this, rats were administrated DHM orally for two weeks at a dose of 300 mg/kg per day, with or without a single i.p. injection of 40 mg/kg MTX on the 9th day of the experiment. MTX caused deterioration in liver structure and function, depicted by an increase in liver enzymes; ALT and AST. Moreover, MTX induced oxidative stress, shown by increasing malondialdehyde and decreasing reduced glutathione and total antioxidant capacity, initiated the inflammatory response via upregulated expression of Toll-like receptor 4 (TLR4) and its downstream transcription factor, nuclear factor-kappa B (NF-κB p65). Consequent to TLR4 signaling cascade, Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammosome was activated and caused caspase 1 mediated transformation of proinflammatory cytokines interleukin 1ß (IL-1ß) and interleukin 18 (IL-18) into their active forms. Interestingly, administering DHM with MTX improved liver structure and function, as well as significantly decreased all oxidative stress and inflammatory signaling. Collectively, DHM possesses antioxidant and anti-inflammatory properties that can ameliorate MTX-induced hepatotoxicity, through down-regulation of liver TLR4/NF-κB and therefore prohibit activation of NLRP3/caspase 1 pathway.

Dose-dependent ameliorating effect of lipoxin A4 on gentamicin-induced nephrotoxicity in rats: The role of TNFα, TGF-ß, ICAM-1, and JNK signaling.

Gentamicin (GEN) possesses a broad range of antimicrobial effects. However, it belongs to the aminoglycosides, and has the greatest potential for nephrotoxic effect above all other antibiotics from this group. This study aims to evaluate the possible protective effect of lipoxin A4 (LXA4) against GEN-induced nephrotoxicity in rats. Nephrotoxicity was induced in male Wistar rats by injection of GEN (80 mg/kg/day, i.p.) for 6 days starting from day 7 of the experiment. Rats were treated with either LXA4 (10 µg/kg/day, i.p.) or LXA4 (50 µg/kg/day, i.p.) for 14 days starting from day 1 of the experiment, along with GEN as the previous schedule. GEN resulted in a significantly elevated renal function in the form of higher serum creatinine and urea levels. Further, GEN induced abnormal renal histopathology including degenerated glomeruli and tubules, with perivascular inflammation and hemorrhage. All of these findings were significantly decreased by the LXA4 administration. Additionally, LXA4 remarkably reduced the increased serum lipid biomarkers. Moreover, LXA4 significantly inhibited the GEN-induced oxidative stress in the kidneys by decreasing the elevated levels of renal malondialdehyde (MDA) and total nitrite while raising the suppressed levels of renal superoxide dismutase (SOD) and serum total antioxidant capacity (TAC). LXA4 inhibited the up-regulated inflammatory mediators ICAM-1, TGFß 1 protein levels, and TNF-α protein expression. Finally, LXA4 suppressed the elevated apoptotic mediators; p-JNK and cleaved caspase-3 expression. Our results proved for the first time that LXA4 ameliorated GEN-induced nephrotoxicity through its antioxidant, anti-inflammatory and anti-apoptotic properties.

TLRs-JNK/ NF-κB Pathway Underlies the Protective Effect of the Sulfide Salt Against Liver Toxicity.

Hydrogen sulfide (H2S) is an endogenously gas transmitter signaling molecule with known antioxidant, anti-inflammatory, and cytoprotective properties. Although accumulating evidence shows the therapeutic potential of H2S in various hepatic diseases, its role in cyclophosphamide (CP)-induced hepatotoxicity remains elusive. The present study was undertaken to investigate the impact of endogenous and exogenous H2S on toll-like receptors (TLRs)-mediated inflammatory response and apoptosis in CP-induced hepatotoxicity. Either an H2S donor (NaHS (100 µM/kg) or an H2S blocker [dl-propargylglycine (PAG) (30 mg/kg, i. p.)], was administered for 10 days before a single ip injection of CP (200 mg/kg). NaHS attenuated conferred hepatoprotection against CP-induced toxicity, significantly decreasing serum hepatic function tests and improving hepatic histopathology. Additionally, NaHS-treated rats exhibited antioxidant activity in liver tissues compared with the CP group. The upregulated hepatic levels of TLR2/4 and their downstream signaling molecules including c-Jun N-terminal kinase (JNK) and nuclear factor-kappa B (NF-κB) were also suppressed by NaHS protective treatment. NaHS showed anti-inflammatory and antiapoptotic effects; reducing hepatic level tumor necrosis factor-alpha (TNF-α) and caspase-3 expression. Interestingly, the cytotoxic events induced in CP-treated rats were not significantly altered upon the blocking of endogenous H2S. Taken together, the present study suggested that exogenously applied H2S rather than the endogenously generated H2S, displayed a hepatoprotective effect against CP-induced hepatotoxicity that might be mediated by TLRs-JNK/NF-κB pathways.

Involvement of NOX-4/JAK/STAT pathway in the protective effect of aprepitant against diclofenac-induced renal toxicity.

AIMS: Aprepitant, a neurokinin-1 (NK1) receptor antagonist, is a clinically approved anti-emetic drug. Recently, inhibition of the NK1 receptor has been reported as a potential nephroprotective strategy. We aimed to assess the pharmacological mechanisms of aprepitant against diclofenac (DIC)-induced renal toxicity. MAIN METHODS: An in vivo study was conducted using twenty-four male Wistar rats, divided into 4 groups. Aprepitant was administered for 5 days (5 mg/kg/day) with or without DIC which was given on the 4th and 5th days (50 mg/kg, i.p.). At the end of the study, renal function biomarkers, renal oxidative parameters, prostaglandin E (PGE-2), and NADPH oxidase (NOX-4) were measured. Histopathological changes as well as expression of renal inflammatory and apoptotic markers (tumor necrosis factor alpha (TNF-α) and caspase-3) were investigated. KEY FINDINGS: DIC caused significant renal damage, as evidenced by deterioration of renal functions, oxidative stress, inflammatory and apoptotic markers, and confirmed by histopathological findings. Pretreatment with aprepitant successfully ameliorated and improved all biochemical and molecular parameters induced by DIC. Moreover, aprepitant restored the decrease in renal PGE-2 concentration and inhibited DIC-activated Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in renal tissues. SIGNIFICANCE: The protective effect of aprepitant is possibly attributed to its anti-oxidant and anti-inflammatory roles via the NOX-4/JAK/STAT pathway.

Cardioprotective effect of allyl isothiocyanate in a rat model of doxorubicin acute toxicity.

Doxorubicin (DOX) is an effective anthracycline chemotherapeutic drug. Nevertheless, the cardiotoxicity adverse effect restricts its clinical benefit. Allyl isothiocyanate (AITC) is a natural antioxidant and anti-inflammatory agent. In the present study, we investigated the effect of AITC on cardiotoxicity of DOX. Thirty-two adult male albino rats were divided into four groups; control, AITC, DOX, and AITC + DOX. AITC was administrated orally (25 mg/kg/day) for 7 days, and DOX was given as a single i.p. injection (15 mg/kg) on the third day. Mortality rate was observed during the experiment. Cardiac toxicity markers (lactate dehydrogenase (LDH), creatine kinase (CK-MB), and cardiac Troponin I (cTn-I)) were evaluated in serum samples obtained from all groups after 48 hours of DOX injection. DOX-treated group showed 40% mortality and a significant increase in cardiac enzymes. This increase was accompanied by degenerated cardiomyocytes, and inflammatory cells infiltrates. Interestingly, AITC administration alleviated myocardial oxidative stress induced by DOX as attenuated the increase in malondialdehyde (MDA), and nitric oxide (NO) while resulted in elevations of the antioxidant reduced glutathione (GSH) level as well as superoxide dismutase (SOD) activity. Furthermore, the inflammatory cytokine, TNF-α, was reduced upon administration of AITC with DOX. The cardio-protection of AITC is attributed to increase the expression of cytoprotective nuclear factor erythroid 2-related factor 2 (Nrf2). Subsequently, heme oxygenase 1 (HO-1) level was elevated by AITC to correct the oxidative stress induced by DOX in the heart. Accordingly, AITC ameliorated acute cardiotoxicity associated with DOX treatment via attenuation of oxidative stress and the induced-tissue inflammatory injury. Abbreviations: DOX: doxrubicin; Nrf2: nuclear factor erythroid 2-related factor 2; HO-1: heme oxygenase 1; AITC: ally isothiocyanate; MDA: malondialdehyde; SOD: superoxide dismutase; GSH: reduced glutathione; TNF-α: tumor necrosis factor alpha.

Nephroprotective effect of exogenous hydrogen sulfide donor against cyclophosphamide-induced toxicity is mediated by Nrf2/HO-1/NF-κB signaling pathway.

AIM: Cyclophosphamide (CP) is an effective anticancer and immunosuppressive agent. However, it induces nephrotoxicity that limits its use. This study explored the effect of H2S, an important biological signaling molecule with a cytoprotective activity, on CP-induced nephrotoxicity. METHODS: Male Wistar rats were treated with saline or NaHS (100 µM/kg/day, H2S donor) or dl-propargylglycine (PAG) (30 mg/kg/day, H2S blocker) for 10 days before a single i.p injection of CP (200 mg/kg). Then, rats were sacrificed, and renal functions were assessed in serum. Histopathological changes, as well as oxidant defenses, inflammatory and apoptotic markers in the renal tissue, were evaluated. KEY FINDINGS: Pretreatment with NaHS significantly reduced the urea and creatinine levels that were elevated in CP-intoxicated rats. NaHS increased the expression of the cytoprotective nuclear factor erythroid 2-related factor 2 (Nrf2) and its subsequent antioxidant proteins; heme oxygenase-1 (HO-1), NAD(P) H quinone oxidoreductase 1 (NQO1), reduced glutathione (GSH) and superoxide dismutase (SOD). Moreover, NaHS prohibited the histopathological damage induced by CP. The inhibition of caspase-3 and nuclear factor kappa B (NF-κB) supported the protective role of H2S against CP-induced kidney damage. On the other hand, blocking endogenous H2S did not provide a more significant deterioration in CP-induced nephrotoxicity in terms of oxidative stress or inflammatory status. SIGNIFICANCE: Exogenous H2S donors exhibited a protective effect against CP-induced nephrotoxicity, which may be mediated via the Nrf2/HO-1/NF-κB signaling pathway. However, endogenous H2S may be insufficient to protect the cell against the induced oxidative damage. This approach provides a novel target to prevent nephrotoxicity of CP.

Structural and Kinetic Studies of the Human Nudix Hydrolase MTH1 Reveal the Mechanism for Its Broad Substrate Specificity.

The human MutT homolog 1 (hMTH1, human NUDT1) hydrolyzes oxidatively damaged nucleoside triphosphates and is the main enzyme responsible for nucleotide sanitization. hMTH1 recently has received attention as an anticancer target because hMTH1 blockade leads to accumulation of oxidized nucleotides in the cell, resulting in mutations and death of cancer cells. Unlike Escherichia coli MutT, which shows high substrate specificity for 8-oxoguanine nucleotides, hMTH1 has broad substrate specificity for oxidized nucleotides, including 8-oxo-dGTP and 2-oxo-dATP. However, the reason for this broad substrate specificity remains unclear. Here, we determined crystal structures of hMTH1 in complex with 8-oxo-dGTP or 2-oxo-dATP at neutral pH. These structures based on high quality data showed that the base moieties of two substrates are located on the similar but not the same position in the substrate binding pocket and adopt a different hydrogen-bonding pattern, and both triphosphate moieties bind to the hMTH1 Nudix motif (i.e. the hydrolase motif) similarly and align for the hydrolysis reaction. We also performed kinetic assays on the substrate-binding Asp-120 mutants (D120N and D120A), and determined their crystal structures in complex with the substrates. Analyses of bond lengths with high-resolution X-ray data and the relationship between the structure and enzymatic activity revealed that hMTH1 recognizes the different oxidized nucleotides via an exchange of the protonation state at two neighboring aspartate residues (Asp-119 and Asp-120) in its substrate binding pocket. To our knowledge, this mechanism of broad substrate recognition by enzymes has not been reported previously and may have relevance for anticancer drug development strategies targeting hMTH1.