Renoprotective effect of diacetylrhein on diclofenac-induced acute kidney injury in rats via modulating Nrf2/NF-κB/NLRP3/GSDMD signaling pathways

Diclofenac (DF)-induced acute kidney injury (AKI) is characterized by glomerular dysfunction and acute tubular necrosis. Due to limited treatment approaches, effective and safe drug therapy to protect against such AKI is still needed. Diacetylrhein (DAR), an anthraquinone derivative, has different antioxidant and anti-inflammatory properties. Therefore, the aim of the current study was to investigate the renoprotective effect of DAR on DF-induced AKI while elucidating the potential underlying mechanism. Our results showed that DAR (50 and 100 mg/kg) markedly abrogated DF-induced kidney dysfunction decreasing SCr, BUN, serum NGAL, and serum KIM1 levels. Moreover, DAR treatment remarkably maintained renal redox balance and reduced the levels of pro-inflammatory biomarkers in the kidney. Mechanistically, DAR boosted Nrf2/HO-1 antioxidant and anti-inflammatory response in the kidney while suppressing renal TLR4/NF-κB and NLRP3/caspase-1 inflammatory signaling pathways. In addition, DAR markedly inhibited renal pyroptosis via targeting of GSDMD activation. Collectively, this study confirmed that the interplay between Nrf2/HO-1 and TLR4/NF-κB/NLRP3/Caspase-1 signaling pathways and pyroptotic cell death mediates DF-induced AKI and reported that DAR has a dose-dependent renoprotective effect on DF-induced AKI in rats. This effect is due to powerful antioxidant, anti-inflammatory, and anti-pyroptotic activities that could provide a promising treatment approach to protect against DF-induced AKI.

Inhibitory effect of diacerein on diclofenac-induced acute nephrotoxicity in rats via modulating SIRT1/HIF-1α/NF-κB and SIRT1/p53 regulatory axes

The aim of this study is to explore the potential of repurposing the antiarthritic drug diacerein (DCN) against diclofenac (DCF)-induced acute nephrotoxicity in rats. Rats were divided into four groups: Group I (CTRL) served as the negative control; Group II (DCF) served as the positive control and was injected with DCF (50 mg/kg/day) for three consecutive days (fourth-sixth) while being deprived of water starting on day 5; Group III (DCF + DCN50) and Group IV (DCF + DCN100) were orally administered DCN (50 and 100 mg/kg/day, respectively) for six days and injected with DCF, while being deprived of water as described above. Changes in kidney function biomarkers were assessed. Levels of MDA and GSH along with NO content in kidney tissues were measured as indicators of oxidative stress status. Histopathological changes of the renal cortex and medulla were evaluated. Changes in renal NF-κB and SIRT-1 levels were immunohistochemically addressed. Western blotting was used to estimate the relative expressions of HIF-1α, p53, and active caspase-3. Our results showed that DCN inhibited kidney dysfunction and suppressed oxidative stress, which were reflected in improved kidney architecture, including less tubular degeneration and necrosis in the cortex and medulla. Interestingly, DCN reduced renal HIF-1α, p53, and active caspase-3 expression and NF-κB activation while increasing renal SIRT1 expression. In conclusion, for the first time, DCN counteracts acute kidney injury induced by DCF in rats by its anti-oxidative, anti-inflammatory, antinecrotic, and anti-apoptotic effects in a dose-dependent manner, which are mainly via targeting SIRT1/HIF-1α/NF-κB and SIRT1/p53 regulatory axes.

Modulation of the crosstalk between Keap1/Nrf2/HO-1 and NF-κB signaling pathways by Tomatidine protects against inflammation/oxidative stress-driven fulminant hepatic failure in mice

Fulminant hepatic failure (FHF) is the terminal phase of acute liver injury, which is characterized by massive hepatocyte necrosis and rapid hepatic dysfunction in patients without preexisting liver disease. There are currently no therapeutic options for such a life-threatening hepatic failure except liver transplantation; therefore, the terminal phase of the underlying acute liver injury should be avoided. Tomatidine (TOM), asteroidal alkaloid, may have different biological activities, including antioxidant and anti-inflammatory effects. Herein, the lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced FHF mouse model was established to explore the protective potential of TOM and the underlying mechanisms of action. TOM pretreatment significantly inhibited hepatocyte necrosis and decreased serum aminotransferase activities in LPS/D-GalN-stimulated mice. TOM further increased the level of different antioxidant enzymes while reducing lipid peroxidation biomarkers in the liver. These beneficial effects of TOM were shown to be associated with targeting of NF-κB signaling pathways, where TOM repressed NF-κB activation and decreased LPS/D-GalN-induced TNF-α, IL-6, IL-1β, and iNOS production. Moreover, TOM prevented LPS/D-GalN-induced upregulation of Keap1 expression and downregulation of Nrf2 and HO-1 expression, leading to increased Nrf2-binding activity and HO-1 levels. Besides, TOM pretreatment repressed LPS/D-GalN-induced upregulation of proliferating cell nuclear antigen (PCNA) expression, which spared the hepatocytes from damage and subsequent repair following the LPS/D-GalN challenge. Collectively, our findings revealed that TOM has a protective effect on LPS/D-GalN-induced FHF in mice, showing powerful antioxidant and anti-inflammatory effects, primarily mediated via modulating Keap1/Nrf2/HO-1 and NF-κB/TNF-α/IL-6/IL-1β/iNOS signaling pathways.

Bioactivity of Eriocephalus africanus essential oil against concanavalin A-induced hepatitis via suppressing immune cell infiltration, inhibiting TNF-α/NF-κB and IFN-γ/STAT1 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Eriocephalus africanus infusion is used as a diuretic and a diaphoretic and is also used in the treatment of gastrointestinal disorders and gynaecological conditions, inflammation and dermal disorders, asthma, coughs, fevers, and painful ailments. The plant has been used traditionally as a medication to cure inflammation and skin problems.

AIM OF THE STUDY

Studying E. africanus essential oil (EAEO) as a potential hepatoprotective measure against concanavalin (Con) A-induced hepatitis in mice and investigating its underlying mechanism.

MATERIALS AND METHODS

Hydro-distilled oil of the fresh plant aerial shoots is subjected to GC/MS analysis. Autoimmune hepatitis (AIH) was induced in mice by intravenous injection of Con A (15 mg/kg). EAEO was administered orally before Con A injection to test its hepatoprotective activity.

RESULTS

GC/MS analysis revealed the presence of 22 compounds representing 99.43% of the oil components. The monoterpene artemisia ketone (41.02%) and the sesquiterpene juniper camphor (14.17%) are the major components. The in vivo study showed that the oil suppressed Con A-induced neutrophil and CD4+T cell infiltration into the liver, restored hepatic redox balance, inhibited Con A-induced elevation of tumor necrosis factor-alpha (TNF-α), interleukin (IL-6), and interferon-gamma (IFN-γ) hepatic levels which were correlated with its ability to suppress nuclear factor kappa B (NF-κB) and Signal Transducer and Activator of Transcription (STAT1) activation in the liver.

CONCLUSION

EAEO showed hepatoprotective potential against Con A-induced hepatitis in mice collectively through selective anti-oxidant, anti-inflammatory, and anti-necrotic effects.

Design, synthesis, and biological investigation of oxadiazolyl, thiadiazolyl, and pyrimidinyl linked antipyrine derivatives as potential non-acidic anti-inflammatory agents

A novel series of 12 antipyrine derivatives containing 1,3,4-oxadiazoles (4a-d), 1,3,4-thiadiazoles (6a-d), and pyrimidines (8a-d), was preparedand assessed for its potential in vitro COX-2 inhibitors. Compared to Celecoxib, compounds 4b-d and 8d were the most potent derivatives c with a half-maximal inhibitory concentration range of 53-69 nM. Considering COX-2 selectivity index, compounds 4 b and 4c were chosen among these most potent derivatives for further investigation. The in vivo ability of compounds 4 b and 4c to counteract carrageenan-induced paw edoema has been assessed and their potential underlying mechanisms have been elucidated and the results have been further validated using molecular docking simulations.

Preventive empagliflozin activity on acute acetic acid-induced ulcerative colitis in rats via modulation of SIRT-1/PI3K/AKT pathway and improving colon barrier

BACKGROUND

Ulcerative colitis (UC) is a chronic colon inflammation that is linked to exposure to environmental factors leading to improper immune responses to enteric microbes in genetically susceptible individuals. This study was designed to explore the possible protective impact of Empagliflozin (EMPA), an anti-diabetic sodium-glucose cotransporter-2 (SGLT2) inhibitor, on acetic acid (AA)-induced UC in rats.

METHOD

Intrarectal instillation of AA (2 ml, 3% v/v) was used to induce UC. EMPA (10 & 30 mg/kg) was administered orally for 11 days.

RESULTS

EMPA successfully counteracted AA-induced UC that was manifested by improving colonic histopathological architecture concomitant with a marked decrease in disease activity index (DAI), colon weight, weight/length ratio, serum lactate dehydrogenase (LDH) activity, and C-reactive protein (CRP) level. Additionally, EMPA successfully restored the disrupted oxidant/antioxidants balance induced by AA. Moreover, EMPA significantly induced silent information regulator-1(SIRT-1) expression along with a significant reduction in phosphatidylinositol-3-Kinase (PI3K), Protein Kinase B (AKT), nuclear factor kappa B (NF-κB), tumor necrosis factor (TNF)-α and interleukins (IL-1β and IL-6) expression in colonic tissues. Furthermore, EMPA successfully improved the colonic barrier that was appeared from the marked induction of tight junction proteins level (occludin and claudin-1).

CONCLUSION

EMPA successfully counteracted AA-induced UC in rats via the modulation of SIRT1/PI3K/AKT/NF-κB inflammatory pathway, normalizing oxidant/antioxidants balance, and improving the integrity of colon barrier.

Diacerein counteracts acetaminophen-induced hepatotoxicity in mice via targeting NLRP3/caspase-1/IL-1β and IL-4/MCP-1 signaling pathways

The current study aims at repurposing the anti-arthritic drug diacerein (DCN) for the treatment of acetaminophen hepatotoxicity and investigating the potential underlying mechanisms. Mice were randomly divided into six groups receiving either no treatment (control group), 20 mg/kg DCN i.p, 400 mg/kg acetaminophen i.p, DCN 4 h before acetaminophen, DCN 2 h after acetaminophen, or 400 mg/kg N-acetylcysteine (NAC) i.p, 2 h after acetaminophen. Biomarkers of liver dysfunction, oxidative stress, and apoptosis were assessed. Hepatic necroinflammatory changes were evaluated along with hepatic expression of NF-κB and caspase-1. The levels of NLRP3, IL-1β, IL-4, MCP-1, and TNF-α in the liver, as well as CYP2E1 mRNA expression, were measured. Diacerein significantly reduced biomarkers of liver dysfunction, oxidative stress, hepatocyte necrosis, and infiltration of neutrophils and macrophages whether administered 4 h before or 2 h after acetaminophen. Further, the effects were comparable to those of NAC. Diacerein also counteracted acetaminophen-induced hepatocellular apoptosis by increasing Bcl-2 and decreasing Bax and caspase-3 expression levels. Moreover, DCN normalized hepatic TNF-α and significantly decreased NF-κB p65 expression. Accordingly, DCN can prevent or reverse acetaminophen hepatotoxicity in mice, suggesting potential utility as a repurposed drug for clinical treatment.

Etanercept attenuates immune-mediated hepatitis induced by concanavalin A via differential regulation of the key effector cytokines of CD4+ T cells

AIMS

The current study aims to investigate the role of the key effector cytokines produced by CD4+T cells in the pathogenesis of Con A-induced liver injury in mice and testing whether etanercept can be repurposed to differentially regulate these cytokines.

MAIN METHODS

Four groups of mice were used: group I: control group, group II: mice received 15 mg/kg Con A i.v, group III: mice received 15 mg/kg etanercept i.p, group IV: mice received both Con A and etanercept as described. Hepatic injury and necroinflammation were assessed. Infiltration of CD4+ T cells and neutrophils were evaluated. Hepatic levels of TNF-α, IL-4, IL-10, and MDA were assigned and expression of NF-κB as well.

KEY FINDINGS

A significant decrease in ALT, AST, and LDH levels occurred when etanercept was injected before Con A. Hepatic necrosis and infiltration of CD4+ T cells and neutrophils were reduced by etanercept. Levels of TNF-α, IL-4, and MDA were significantly decreased in group IV compared to group II while that of IL-10 was increased. Also, number of NF-κB positive cells was significantly low in group IV.

SIGNIFICANCE

The study elucidates an interplay between the two effector cytokines of CD4+ T cells, TNF-α and IL-4, and their key role in Con A-induced liver injury. Additionally, our results showed that etanercept could be repurposed to differentially regulate effector cytokines produced by CD4+ T cells. Not only TNF-α, but also IL-4 signaling pathways, through which it exerts immunomodulatory, anti-inflammatory, and anti-oxidant effects leading to attenuation of Con A-induced liver injury.

Retinoic acid modulates IL-4, IL-10 and MCP-1 pathways in immune mediated hepatitis and interrupts CD4+ T cells infiltration

AIMS

Immune mediated liver injury includes activation of different immune pathways that requires various modalities to control their consequences. The current study involves evaluation of retinoic acid (RA) modulatory effects on immune responses induced in concanavalin A (ConA) model of acute hepatitis.

MAIN METHODS

Mice were divided as follows: Control group; RA group: received 35 mg/kg RA; ConA group: received 15 mg/kg ConA; ConA + RA group: received ConA and RA as described. Liver function biomarkers were measured in addition to malondialdehyde as lipid peroxidation biomarker. Liver tissue sections were scored for necro-inflammation, neutrophils infiltration, CD4+ T cells infiltration and NF-κb positive cells. Effect on hepatic levels of TNF-α, IL-4, IL-10 and MCP-1 was evaluated as well.

KEY FINDINGS

Injection of RA before ConA significantly (p < 0.001) decreased ALT, AST and LDH levels compared to their levels in ConA group. Hepatic infiltration of neutrophils and CD4+ T cells was markedly (p < 0.001) reduced by RA. Hepatic injury, necrosis and expression of NF-κb were significantly decreased by RA when injected before ConA challenge. A significant decrease in the measured cytokines TNF-α and IL-4 was observed in ConA + RA group in addition to a decrease in MCP-1 level. On the other hand, IL-10 was significantly increased in the latter group compared to ConA group.

SIGNIFICANCE

RA can protect against ConA-induced hepatitis through: interrupting early inflammatory response as neutrophils, monocytes and CD4+ T cells infiltration, modulating IL-4 level and subsequent production of TNF-α and NF-κb activation, mitigating second inflammatory responses through increasing IL-10 liver production.

Thearubigins protect against acetaminophen-induced hepatic and renal injury in mice: biochemical, histopathological, immunohistochemical, and flow cytometry study

CONTEXT

Acetaminophen toxicity is used as a model for studying chemical toxicity. N-acetylcysteine (NAC) is used for the treatment of hepatotoxicity; however, there is no specific therapy for nephrotoxicity.

OBJECTIVE

This study was designed to investigate the potential protective effect of black tea extract (BTE) and its main phenolic pigment, thearubigins (TRs), against acetaminophen (APAP)-induced hepatic and renal injury in mice.

MATERIALS AND METHODS

Besides control groups, six groups (n = 8) were given intraperitoneally APAP (300 mg/kg) and then after 1.5 hours were treated intraperitoneally as follows: NAC (318 mg/kg), BTE (3%, 4.5%), and TRs (50, 60, and 70 mg/kg). Six hours post-APAP injection, blood was collected for biochemical measurements. Later, liver and kidneys were removed for histopathological, immunohistochemical, and flow cytometry studies.

RESULTS

APAP increased alanine aminotransferase and malondialdehyde and decreased glutathione levels in blood. Treatments significantly reversed these changes mostly with NAC and TRs70. TRs showed dose-dependent significant differences. The APAP-induced central lobular hepatic necrosis and increased TUNEL positivity were mild with co-administration of NAC and TRs (60, 70) while moderate with co-administration of BTE (3, 4.5) and TRs50. The APAP-increased serum creatinine level was significantly reversed by treatments (mostly TRs60, 70). The APAP-induced renal tubular epithelial degeneration and necrosis were mild with co-administration of TRs (60, 70) while moderate with co-administration of NAC, BTE (3, 4.5), and TRs50. The APAP-accumulated apoptotic cells in sub-G1 phase were significantly decreased by treatments, mostly by NAC and TRs70 in the liver and TRs (60, 70) in kidneys.

CONCLUSION

Thearubigins protected against acetaminophen-induced hepatotoxicity and nephrotoxicity in mice possibly through their antioxidant activity.