Quercetin modulates iNOS, eNOS and NOSTRIN expressions and attenuates oxidative stress in warm hepatic ischemia-reperfusion injury in rats

Urtica dioica L. Leaf Extract Dose-Dependently Modulates Oxidative Stress in the Kidney and Exerts Anti-Fibrotic and Anti-Inflammatory Properties by the Molecular Mechanisms Independent of NRF-2 Signalization Mirroring the Effects of Losartan in SHR

Previously, we confirmed systemic antihypertensive and antioxidant properties of Urtica dioica L. leaf extract (UE) in spontaneously hypertensive rats (SHR). Here, we aimed to evaluate whether UE can alter the NO and Nrf-2 signaling to prevent local oxidative stress and kidney damage in the model of essential hypertension. SHR were divided into five groups: SHRC-control, received 0.5 mL/day of water, SHR+L received 10 mg/kg/day of losartan, SHR+UE10, SHR+UE50, and SHR+UE200 received 10, 50, and 200 mg/kg/day during next 4 weeks. At the end of the experiment, urine samples were collected for albuminuria and nitrate/nitrite assessment. Mean arterial pressure (MAP) was measured, and blood samples were collected for plasma creatinine evaluation. Kidneys were analyzed for nitrate/nitrite, oxidative stress, and target molecules by biochemical, Western blot, and immunofluorescent techniques. Losartan and UE50 significantly reduced MAP, albuminuria, oxidative stress, fibroinflammatory markers, and NRF-2/CAT/SOD signaling, with a significant increase in 6-nitrotryptophan and eNOS expressions compared to control. The effects of UE showed dose dependence. Beneficial effects of UE and losartan were independent of NRF-2 signalization in SHR. Interestingly, all treatments induced the increase in 6-nitrotryptophan expression, thus further studies are needed to elucidate the mechanisms of such nitrated tryptophan.

Leukocyte cell-derived chemotaxin 2 (LECT2) regulates liver ischemia-reperfusion injury

Background and aim

Hepatic ischemia-reperfusion injury (IRI) is a significant challenge in liver transplantation, trauma, hypovolemic shock, and hepatectomy, with limited effective interventions available. This study aimed to investigate the role of leukocyte cell-derived chemotaxin 2 (LECT2) in hepatic IRI and assess the therapeutic potential of Lect2-short hairpin RNA (shRNA) delivered through adeno-associated virus (AAV) vectors.

Materials and methods

This study analyzed human liver and serum samples from five patients undergoing the Pringle maneuver. Lect2-knockout and C57BL/6J mice were used. Hepatic IRI was induced by clamping the hepatic pedicle. Treatments included recombinant human LECT2 (rLECT2) and AAV-Lect2-shRNA. LECT2 expression levels and serum biomarkers including alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and blood urea nitrogen (BUN) were measured. Histological analysis of liver necrosis and quantitative reverse-transcription polymerase chain reaction were performed.

Results

Serum and liver LECT2 levels were elevated during hepatic IRI. Serum LECT2 protein and mRNA levels increased post reperfusion. Lect2-knockout mice had reduced weight loss; hepatic necrosis; and serum ALT, AST, creatinine, and BUN levels. rLECT2 treatment exacerbated weight loss, hepatic necrosis, and serum biomarkers (ALT, AST, creatinine, and BUN). AAV-Lect2-shRNA treatment significantly reduced weight loss, hepatic necrosis, and serum biomarkers (ALT, AST, creatinine, and BUN), indicating therapeutic potential.

Conclusions

Elevated LECT2 levels during hepatic IRI increased liver damage. Genetic knockout or shRNA-mediated knockdown of Lect2 reduced liver damage, indicating its therapeutic potential. AAV-mediated Lect2-shRNA delivery mitigated hepatic IRI, offering a potential new treatment strategy to enhance clinical outcomes for patients undergoing liver-related surgeries or trauma.

The Impact of General Anesthesia on Redox Stability and Epigenetic Inflammation Pathways: Crosstalk on Perioperative Antioxidant Therapy

Worldwide, the prevalence of surgery under general anesthesia has significantly increased, both because of modern anesthetic and pain-control techniques and because of better diagnosis and the increased complexity of surgical techniques. Apart from developing new concepts in the surgical field, researchers and clinicians are now working on minimizing the impact of surgical trauma and offering minimal invasive procedures due to the recent discoveries in the field of cellular and molecular mechanisms that have revealed a systemic inflammatory and pro-oxidative impact not only in the perioperative period but also in the long term, contributing to more difficult recovery, increased morbidity and mortality, and a negative financial impact. Detailed molecular and cellular analysis has shown an overproduction of inflammatory and pro-oxidative species, responsible for augmenting the systemic inflammatory status and making postoperative recovery more difficult. Moreover, there are a series of changes in certain epigenetic structures, the most important being the microRNAs. This review describes the most important molecular and cellular mechanisms that impact the surgical patient undergoing general anesthesia, and it presents a series of antioxidant therapies that can reduce systemic inflammation.

Role of Zinc Supplementation on Ischemia/Reperfusion Injury in Various Organs

Ischemia-reperfusion (I/R) injury is a serious condition which is associated with myocardial infarction, stroke, acute kidney injury, trauma, circulatory arrest, sickle cell disease, and sleep apnea and can lead to high morbidity and mortality. Salts of zinc (Zn) are commonly used by humans and have protective effects against gastric, renal, hepatic, muscle, myocardial, or neuronal ischemic injury. The present review evaluates molecular mechanisms underlying the protective effects of Zn supplement against I/R injury. Data of this review have been collected from the scientific articles published in databases such as Science Direct, Scopus, PubMed, and Scientific Information Database from 1991 to 2019. Zn supplementation increased the decreased parameters including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione (GSH), metallothionein (MT), protein sulfhydryl (P-SH), and nuclear factor-erythroid 2-related factor-2 (Nrf2) expression and decreased the increased elements such as endoplasmic reticulum (ER) stress, mitochondrial permeability transition pore (mPTP) opening, malondialdehyde (MDA), serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and microRNAs-(122 and 34a), apoptotic factors, and histopathological changes. Zn also increases phosphatidylinositol 3-kinase (PI3K)/Akt and glycogen synthase kinase-3β (GSK-3β) phosphorylation and preserves protein kinase C isoforms. It is suggested that Zn can be administered before elective surgeries for prevention of side effects of I/R injury.

A systematic review on hepatoprotective activity of quercetin against various drugs and toxic agents: Evidence from preclinical studies

Quercetin is one of the most abundant flavonoids in human diet that has been reported to exhibit a wide range of pharmacological properties. The biochemical and molecular mechanisms involved in the hepatoprotective activity of quercetin were discussed in this review. Quercetin exhibited hepatoprotective activity against 2-butoxyethanol, acrylamide, acrylonitrile, aflatoxin B1, aroclor-1254, arsenic, sodium arsenite, azathioprine, cadmium chloride, carbon tetrachloride, chlorpyrifos, cyclosporine A, diazinon, dimethylnitrosamine, doxorubicin, epirubicin, ethanol, fenvalerate, isoniazide, rifampicin, lead acetate, lindane, D-galactosamine, methotrexate, methylmercury, nickel sulfate, paracetamol, perfluorooctanoic acid, polychlorinated biphenyls, pyrrolizidine alkaloid clivorine, rotenone, sodium fluoride, streptazotocin, tert-butyl hydroperoxide, thioacetamide, titanium dioxide, tumor necrosis factor-α, tripterygium glycoside, triptolide, ultraviolet A light, concavalin A, bisphenol, and ischemia-induced hepatotoxicity in various animal models due to its antioxidant, free radical-scavenging,anti-inflammatory, antiapoptotic, and cytochrome P450 2E1 (CYP2E1) inhibitory activities. In this review, we provide an overview of the possible mechanisms by which quercetin reduced the hepatotoxicity of different hepatotoxicants. This will help the toxicologists, pharmacologists, and chemists to develop new safer pharmaceutical products with quercetin and other hepatotoxicants.

The Effect of Zinc Sulfate on miR-122, miR-34a, Atioxidants, Biochemical and Histopathological Parameters Following Hepatic Ischemia/Reperfusion Injury in Rats

Liver ischemia-reperfusion (IR) injury is a situation which occurs in various conditions such as pringle maneuver and liver transplantation. The regulatory effect of zinc sulfate (ZnSO4) is an important trace element on several liver disorders well known, but its effects on microRNA_S (miR-122 and miR-34a) have not been evaluated. The goal of this study was to identify the protective effects of ZnSO4 on IR-induced liver injury, in particular, microRNA_S in rats. Thirty-two male Wistar rats were randomly assigned into four groups (eight each group): sham, IR, ZnSO4 pretreatment, and ZnSO4 + IR groups. In sham and ZnSO4 pretreatment groups, animals received normal saline (N/S, 2 ml/kg) and ZnSO4 (5 mg/kg) for 7 consecutive days intraperitoneally (ip), then only laparotomy was performed. In IR and ZnSO4 + IR groups, N/S and ZnSO4, respectively, were given with the same dose, time, and route, before induction of ischemia for 45 min followed by reperfusion for 60 min. Blood sample was taken for biochemical and microRNAs analysis. Tissue specimens also were obtained for the measurements of antioxidant activities and histopathological evaluations. Our results showed that ZnSO4 pretreatment ameliorated histopathological changes decreased the increased serum levels of liver enzymes, miR-122 and miR-34a, and enhanced the decreased activity of antioxidant enzymes following hepatic IR injury. The present study indicated that ZnSO4 had potential hepatoprotective action against IR-induced injury. Therefore, it has been suggested that it can be administered as an anti-miR before elective hepatic surgeries for prevention of this complication.

Vildagliptin Attenuates Hepatic Ischemia/Reperfusion Injury via the TLR4/NF-κB Signaling Pathway

The Toll-like receptor-4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway is vital in the pathogenesis of hepatic ischemia/reperfusion (HIR) injury. Dipeptidyl peptidase-4 (DPP4) inhibitors exert protective effects on IR injury of the kidney, heart, and lung; however, their effect on the liver is still unknown. Thus, the purpose of this study was to examine whether pretreatment with vildagliptin (Vilda), a DPP4 inhibitor, produces hepatic protection against IR injury and to investigate its influence on TLR4/NF-κB signaling in a rat model. Thirty male Wistar rats were divided into 3 groups: the sham group: subjected to a sham operation and received normal saline; the HIR group: subjected to HIR and received normal saline; and the Vilda + HIR group: subjected to HIR with pretreatment of 10 mg/kg/day Vilda for 10 days intraperitoneally. Hepatic ischemia lasted for 45 minutes followed by 3-hour reperfusion; then blood and liver samples were collected for biochemical and histopathological examination. The HIR group produced a significant increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA), nitric oxide (NO), and tumor necrosis factor alpha (TNF-α) levels and a significant reduction in the hepatic catalase level in comparison to the sham group. Moreover, a significant upregulation of gene and protein expressions of TLR4, NF-κB, and high-mobility group box-1 (HMGB1) along with caspase-3 protein expression was observed in the HIR group when compared with the sham group. Histopathological examination of the liver from the HIR group showed necrosis, sinusoidal congestion, hemorrhage, and hepatocyte degeneration. Administration of Vilda ameliorated the biochemical and histopathological changes caused by HIR. Vildagliptin showed for the first time a hepatoprotective effect in HIR injury through downregulation of TLR4/NF-κB/HMGB1 and caspase-3 hepatic expressions.

Protective effects of crocin and zinc sulfate on hepatic ischemia-reperfusion injury in rats: a comparative experimental model study

OBJECTIVES

The aim of this study was to investigate the comparative protective effects of separate and combined pretreatment with Cr and ZnSO4 on serum levels of miR-122, miR-34a, liver function tests, protein expression of Nrf2 and p53, and histopathological changes following IR-induced hepatic injury.

MATERIALS AND METHODS

Fifty-six male Wistar rats randomly assigned into seven groups (n=8). Sham (S), IR, crocin pretreatment (Cr), and crocin pretreatment+IR (Cr+IR), ZnSO4 pretreatment (ZnSO4), ZnSO4 pretreatment+IR (ZnSO4+IR) and their combination (Cr+ZnSO4+IR) groups. In sham, ZnSO4 and Cr groups, animals received normal saline (N/S, 2ml/day), Cr (200mg/kg) and ZnSO4 (5mg/kg) for 7 consecutive days (intraperitoneally; i.p), then only laparotomy was performed. In IR, Cr+IR, ZnSO4+IR and Cr+ZnSO4+IR groups, rats received N/S, Cr and ZnSO4 with same dose and time, then underwent a partial (70%) ischemia for 45min that followed by reperfusion for 60min. Blood sample was taken for biochemical and microRNAs assay, tissue specimens were obtained for antioxidants, protein expression, histopathological and immunohistochemical evaluations.

RESULTS

The results showed that Cr and ZnSO4 increased antioxidants activity and expression of Nrf2, decreased serum levels of liver enzymes, miR-122, miR-34a, p53 expression and also ameliorated histopathological abnormality. However, their combination caused more improvement on IR-induced liver injury.

CONCLUSION

This study demonstrated that Cr, ZnSO4 and their combination through increasing antioxidant activity and Nrf2 expression, decreasing the serum levels of liver enzymes, miR-122, 34a, p53 expression, and amelioration of histopathological changes, protected liver against IR-induced injury.

Protective effect of Momordica charantia water extract against liver injury in restraint-stressed mice and the underlying mechanism

Background: Momordica charantia is used in China for its jianghuo (heat-clearing and detoxifying) effects. The concept of shanghuo (the antonym of jianghuo, excessive internal heat) in traditional Chinese medicine is considered a type of stress response of the body. The stress process involves internal organs, especially the liver. Objective: We hypothesized that Momordica charantia water extract (MWE) has a hepatoprotective effect and can protect the body from stress. The aim of this study was to investigate the possible effects of MWE against liver injury in restraint-stressed mice. Design: The mice were intragastrically administered with MWE (250, 500 and 750 mg/kg bw) daily for 7 days. The Normal Control (NC) and Model groups were administered distilled water. A positive control group was intragastrically administered vitamin C 250 mg/kg bw. After the last administration, mice were restrained for 20 h. Results: MWE reduced the serum AST and ALT, reduced the NO content and the protein expression level of iNOSin the liver; significantly reduced the mitochondrial ROS content, increased the mitochondrial membrane potential and the activities of mitochondrial respiratory chain complexes I and II in restraint-stressed mice. Conclusions: The results indicate that MWE has a protective effect against liver injury in restraint-stressed mice. Abbreviations: MWE: Momordica charantia water extract; M. charantia: Momordica charantia L.; ROS: reactive oxygen species; NO: nitric oxide; iNOS: inducible nitric oxide synthase; IL-1β: interleukin-1 beta; TNF-α: tumor necrosis factor alpha; IL-6: interleukin 6; IFN-γ: interferon gamma; VC: vitamin C; ALT: alanine transaminase; AST: aspartate aminotransferase; GSH: glutathione; GSH-PX: glutathione peroxidase; MDA: malondialdehyde; BCA: bicinchoninic acid; TBARS: thiobarbituric acid reactive substances; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; JC-B: Janus Green B; DW: dry weight; FC: Folin-Ciocalteu; GAE: gallic acid equivalents; bw: body weight; NC: normal control group; Model: restraint stress model group; VC: positive control vitamin C group, 250 mg/kg bw; MWEL: Momordica charantia water extract low-dose group, 250 mg/kg bw; MWEM: Momordica charantia water extract middle-dose group, 500 mg/kg bw; MWEH: Momordica charantia water extract high-dose group, 750 mg/kg bw; HE: hematoxylin and eosin; ORAC: total oxygen radical absorbance capacity; ABAP: dihydrochloride; ATP: adenosine triphosphate.