Hepatoprotective effect of sitagliptin against methotrexate induced liver toxicity

Sinapic acid mitigates methotrexate-induced hepatic injuries in rats through modulation of Nrf-2/HO-1 signaling

The present research has been investigated to study the protective outcomes of sinapic acid (SA) against methotrexate (MTX) encouraged liver damage in rats by modulating the Nrf2/HO-1 and NF-κB signaling pathways. The animals were arbitrarily allocated into four groups: group I rats administered a 0.5% carboxymethyl cellulose (CMC) vehicle orally for 15 consecutive days with a single intravenous standard saline injection (0.9% NaCl) on day seven. Groups II, III, and IV were injected intraperitoneally with 20 mg MTX/kg on 7th day. Animals in group III and IV were treated orally for 14 days with 20 mg of SA/kg dissolved daily in 0.5% CMC respectively. In all experimental groups, liver function, biochemical, histopathological and molecular changes were evaluated. MTX-induced changes in liver function indices like ALT, AST, and ALP are substantially restored with SA pretreatment. Moreover, antioxidant defense mechanisms (GSH, SOD, and CAT) and oxidative/nitrostative stress (MDA and NO) and inflammatory cytokine (TNF-α, IL-β and MPO) were also substantially restored. Furthermore, the conclusions indicate that SA prevents the hepatic damage caused by MTX through apoptosis inhibition and stimulation of Nrf2/HO-1-medial antioxidant enzymes by NF-κB inhibition. Histological findings have shown that SA therapy has greatly protected liver damage caused by MTX.

Ameliorative effect of metformin on methotrexate-induced genotoxicity: An in vitro study in human cultured lymphocytes

Methotrexate is a folic acid antagonist that has been shown to be genotoxic to normal healthy cells. Metformin is an insulin-sensitizing agent, with multiple potential pharmacodynamic profiles. The aim of the present study was to evaluate the genotoxic effect of methotrexate on DNA and the potential ameliorative effect of metformin on chromosomal damage induced by methotrexate. The present study was performed in vitro, and the frequency of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) in human cultured lymphocytes were measured. Blood samples from five non-smoking healthy men aged 20-35 years were donated and used in the present study. Treatment of cultured blood cells with methotrexate significantly increased the number of cells with CAs (P<0.0001) and the frequency of SCEs (P<0.0001). The chromosomal injury induced by methotrexate was significantly reduced by pretreatment of the samples with metformin (P<0.0001). Importantly, the treatment of the cells with metformin alone did not affect the frequency of SCEs compared with the control group (P>0.05). Additionally, methotrexate and metformin alone, and combined, induced significant decreases in the proliferative index compared with the control group (P<0.05). In conclusion, metformin ameliorated the genotoxicity induced by methotrexate in cultured human lymphocytes.

Hepatotoxic potentials of methotrexate: Understanding the possible toxicological molecular mechanisms

Methotrexate (MTX) is one of the most effective and widely used drugs in the management of autoimmune and dermatological diseases. Rheumatoid arthritis and psoriasis patients who are under long term MTX-therapy are at high risk of developing a liver injury. Accumulation of intracellular MTX-polyglutamate (MTX-PG), a metabolite of MTX triggers oxidative stress, inflammation, steatosis, fibrosis, and apoptosis in hepatocytes. MTX-PG causes oxidative stress in the liver by inducing lipid peroxidation thereby releasing reactive oxygen species and suppressing antioxidant response elements. MTX-PG induces several pro-inflammatory signaling pathways and cytokines such as tumor necrosis factor-α, nuclear factor kappa B and interleukin 6 (IL-6), IL- β1, IL-12. MTX-PG depletes hepatic folate level and decreases RNA and DNA synthesis leading to hepatocyte death. MTX-PG inhibits 5-aminoimidazole-4-carboxamide ribonucleotide transformylase enzyme and thereby causes accumulation of intracellular adenosine, which causes activation of hepatic stellate cells, extracellular matrix accumulation and hepatic fibrosis. MTX-PG induces hepatocytes apoptosis by activation of caspase 3 via the intrinsic pathway. Clinically, aggravation of underlying fatty liver to non-alcoholic steatohepatitis with fibrosis seems to be an important mechanism of liver injury in MTX-treated RA patients. Therefore, there is a need for monitoring liver injury in RA, psoriatic and cancer patients with NAFLD and fibrosis risk factors during MTX treatment. This review summarizes the possible molecular mechanism of MTX-induced hepatotoxicity. It may pave the way for early detection of liver injury and develop novel strategies for treating MTX mediated hepatotoxicity.

The Protective Effect of Cilostazol in Genotoxicity Induced by Methotrexate in Human Cultured Lymphocytes

BACKGROUND

Methotrexate is an antagonist of folic acid that has been shown to be genotoxic to healthy body cells via induction of oxidative stress. Cilostazol is a phosphodiesterase III inhibitor and a potent antioxidant drug.

OBJECTIVE

To evaluate the potential protective effect of cilostazol on methotrexate genotoxicity.

METHODS

The genotoxic effect of methotrexate by measuring the frequency of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) in human cultured lymphocytes was studied.

RESULTS

Methotrexate significantly increased the frequency of CAs and SCEs (p < 0.0001) as compared to control cultures. This chromosomal damage induced by methotrexate was considerably decreased by pretreatment of the cells with cilostazol (P < 0.01). Moreover, the results showed that methotrexate resulted in a notable reduction (P < 0.01) in cells kinetic parameters, the mitotic index (MI) and the proliferative index (PI). Similarly, cilostazol significantly reduced the mitotic index, which could be related to the anti-proliferative effect (P < 0.01).

CONCLUSION

Methotrexate is genotoxic, and cilostazol could prevent the methotrexate-induced chromosomal damage with no modulation of methotrexate-induced cytotoxicity.

Apigenin alleviates methotrexate-induced liver and kidney injury in mice

Methotrexate (MTX) is a drug used in the treatment of various types of cancer and inflammatory diseases, but its clinical use has been restricted due to its toxicity. Apigenin (API) is an effective flavonoid with antioxidant and anti-inflammatory properties. The aim of this study was to determine the protective effect of API against MTX-induced liver and kidney toxicity. Four groups with 12 male mice each were used. The control and API groups were received 0.9% saline (ip) and API (3 mg/kg ip) for 4 days, respectively. The MTX group were given a single dose of MTX (20 mg/kg ip) on the fourth day. The MTX + API group were administered API for 7 days and then MTX on fourth day. Blood, liver and kidney were collected to evaluate tissue injury markers, oxidative stress biomarkers, and histopathological and immunohistochemical assessments. In MTX-treated group, significant increases in aminotransferases activities, creatinine and malondialdehyde (MDA) levels and significant decreases in catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase1 (SOD1) activities and glutathione (GSH) levels were determined compared to the control group. Furthermore, histopathological changes and significant increases in caspase-3, C-reactive protein (CRP), granulocyte colony-stimulating factor (G-CSF), and inducible nitric oxide synthase (iNOS) expressions were detected in both liver and kidney tissues of MTX-treated mice. Pretreatment with API alleviates liver and kidney toxicity by attenuating oxidative stress and tissue injury markers, histopathological alterations, and apoptosis and inflammation. These results suggest that API has a protective effect against oxidative stress and liver-kidney toxicity induced by MTX.

Naringin alleviates methotrexate-induced liver injury in male albino rats and enhances its antitumor efficacy in HepG2 cells

Methotrexate (MTX) is an efficient chemotherapeutic and immunosuppressant drug, but the hepatotoxicity of MTX limits its clinical use. Naringin (Nar) is a flavonoid derived from Citrus paradise, and has been shown to possess several pharmacological activities, including free-radical scavenging and antioxidant properties. In the present study, we first tested the possible protective effects of multiple doses of Nar against MTX-induced acute hepatotoxicity in rats, and then we investigated the growth inhibition and apoptotic effects of MTX and/or Nar against the HepG2 hepatocarcinoma cell line. Our in vivo results showed that Nar significantly reduced MTX-induced increases in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin levels. Nar also reduced MTX-induced oxidative stress by significantly reducing liver malondialdehyde (MDA) and nitric oxide (NO) content and increasing superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH). In addition, Nar significantly counteracted MTX-induced increases in hepatic interleukin-6 and tumor necrosis factor-α (TNF-α). Further, Nar greatly protected hepatocyte ultrastructure against MTX-induced injury. In contrast, in vitro MTX and/or Nar treatment of HepG2 cells for 48 h exhibited a cytotoxic effect and induced apoptosis in a dose-dependent manner mediated by a significant increase in the Bax/Bcl-2 protein expression ratio. Noticeably, Nar potentiated the MTX effect on the Bax/Bcl-2 ratio. In conclusion, Nar decreased MTX-induced functional and ultrastructural liver damage in a tumor-free animal model. Also, our data introduce MTX and Nar as promising antiproliferative agents with a distinctive mode of action, inducing apoptosis in HepG2 tumor cells through activation of Bax and down-regulation of Bcl-2 protein expression.

Hepatoprotective effect of the tyrosine kinase inhibitor nilotinib against cyclosporine-A induced liver injury in rats through blocking the Bax/Cytochrome C/caspase-3 apoptotic signaling pathway

Cyclosporine-A (CsA) is a powerful immunosuppressive agent and hepatotoxicity results from CsA treatment. This study aimed to elucidate the effectiveness of tyrosine kinase inhibitor nilotinib against CsA-induced hepatotoxicity and the underlying molecular mechanisms. Male Sprague-Dawley rats were allocated into four groups and received drugs for 28 days as follows: Control group: received vehicle, Nilotinib group: received nilotinib (20 mg/kg orally), CsA group: received CsA by subcutaneous injection (20 mg/kg daily), CsA-nilotinib: received nilotinib and CsA. Serum lactate dehydrogenase (LDH), liver function biomarkers, hepatic levels of oxidative stress biomarkers, nuclear factor erythroid-2 like-2 (Nrf2), total antioxidant capacity (TAC), interleukin-2 (IL-2), IL-1β, IL-6, and cytochrome-C were assessed. Additionally, the protein levels and mRNA expression of Bcl2 associated X protein (Bax), caspase-3, nuclear factor-κB (NF-κB), hemoxygenase-1 (HO-1) were measured. Moreover, liver tissues were assessed histopathologically using hematoxylin-eosin and Masson trichrome stain. Nilotinib treatment decreased serum LDH, alanine aminotransferase, aspartate aminotransferase, and γ-glutamyltransferase (γ-GT), hepatic malondialdehyde, and cytochrome-C. It also increased superoxide dismutase, reduced glutathione, glutathione reductase, glutathione peroxidase, glutathione-S-transferase (GST), TAC, and Nrf2 compared to CsA-injected rats. In addition, nilotinib decreased NF-κB, IL-1β, IL-6, Bax, and caspase-3, while elevated IL-2 and immunoexpression of HO-1. Additionally, mRNA expression of Bax and caspase-3 was elevated and that of HO-1 and inhibitory protein κB-α was reduced in the nilotinib-treated group. Moreover, nilotinib significantly attenuated CsA-induced histopathological alterations. Nilotinib may have a promising role as a hepato-protective through its antiapoptotic, antioxidant, and anti-inflammatory effects.

Protective effects of apigenin on altered lipid peroxidation, inflammation, and antioxidant factors in methotrexate-induced hepatotoxicity

Methotrexate (MTX) is used as an effective chemotherapeutic agent against autoimmune diseases and tumors. Oxidative stress and inflammation are involved in the pathogenesis of MTX-induced damage. This study aimed at examining the ameliorating effects of apigenin (API) as a natural antioxidant on MTX-induced hepatotoxicity. The rats were classified into four groups: group I: normal saline-treated, group II: MTX-treated (20 mg/kg, ip, single dose at day 7), group III: MTX + API-treated (20 mg/kg, po), and group IV: API-treated. API was administrated for 9 days. Alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) were used as biochemical factors of MTX-induced hepatic injury. In hepatic tissues, the levels of malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), and activities of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) as oxidative stress markers along with inflammatory factors such as tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta (IL-1β) were assessed. Our results showed that MTX administration significantly increased ALP, ASP, ALT, MDA, NO, TNF-α, and IL-1β levels and significantly decreased antioxidant factors such as GSH, CAT, GPx, and SOD. The API pretreatment group showed a significant rise in hepatic antioxidant markers, besides significant reductions in the serum levels of AST, ALT, and ALP and hepatic content of MDA, TNF-α, NO, and IL-1β. In addition, the hepatoprotective effect of API was confirmed by histological evaluation of the liver. API can prevent MTX-induced hepatotoxicity through mitigation of oxidative stress and inflammation.

Carveol a Naturally-Derived Potent and Emerging Nrf2 Activator Protects Against Acetaminophen-Induced Hepatotoxicity

Acetaminophen (N-acetyl p-aminophenol or APAP) is used worldwide for its antipyretic and anti-inflammatory potential. However, APAP overdose sometimes causes severe liver damage. In this study, we elucidated the protective effects of carveol in liver injury, using molecular and in silico approaches. Male BALB/c mice were divided into two experimental cohorts, to identify the best dose and to further assess the role of carveol in the nuclear factor E2-related factor; nuclear factor erythroid 2; p45-related factor 2 (Nrf2) pathway. The results demonstrated that carveol significantly modulated the detrimental effects of APAP by boosting endogenous antioxidant mechanisms, such as nuclear translocation of Nrf2 gene, a master regulator of the downstream antioxidant machinery. Furthermore, an inhibitor of Nrf2, called all-trans retinoic acid (ATRA), was used, which exaggerated APAP toxicity, in addition to abrogating the protective effects of carveol; this effect was accompanied by overexpression of inflammatory mediators and liver = 2ltoxicity biomarkers. To further support our notion, we performed virtual docking of carveol with Nrf2-keap1 target, and the resultant drug-protein interactions validated the in vivo findings. Together, our findings suggest that carveol could activate the endogenous master antioxidant Nrf2, which further regulates the expression of downstream antioxidants, eventually ameliorating the APAP-induced inflammation and oxidative stress.

Activation of autophagy by sitagliptin attenuates cadmium-induced testicular impairment in rats: Targeting AMPK/mTOR and Nrf2/HO-1 pathways

AIMS

Cadmium (Cd) is a prevalent environmental contaminant that incurs deleterious health effects, including testicular impairment. Sitagliptin, a selective dipeptidyl peptidase-4 (DPP-4) inhibitor, has demonstrated marked cardio-, hepato-, and reno-protective actions, however, its impact on Cd-triggered testicular dysfunction has not been formerly investigated. Hence, the present study aimed to explore the probable beneficial impact of sitagliptin against Cd-evoked testicular impairment which may add to its potential clinical utility. The underlying mechanisms pertaining to the balance between testicular autophagy and apoptosis were explored, including the AMPK/mTOR and Nrf2/HO-1 pathways.

MATERIALS AND METHODS

The testicular tissues were examined using histopathology, immunohistochemistry, Western blotting, and ELISA. Sitagliptin (10 mg/kg/day, by gavage) was administered for 4 consecutive weeks.

KEY FINDINGS

Sitagliptin attenuated the testicular impairment via improvement of the relative testicular weight, sperm count/motility, sperm abnormalities, and serum testosterone. Additionally, sitagliptin counteracted Cd-induced histologic aberrations/disrupted spermatogenesis. Interestingly, sitagliptin augmented the defective autophagy as demonstrated by upregulating Beclin 1 protein expression and lowering p62 SQSTM1 protein accumulation. These effects were mediated via the activation of testicular AMPK/mTOR pathway as proven by increasing p-AMPK (Ser485, Ser491)/total AMPK and diminishing p-mTOR (Ser2448)/total mTOR protein expression. Additionally, sitagliptin suppressed the testicular apoptotic events via downregulating Bax and upregulating Bcl-2 protein expression. In tandem, sitagliptin suppressed the oxidative stress through lowering lipid peroxides and activating Nrf2/HO-1 pathway via upregulating the protein expression of Nrf2, and the downstream effectors HO-1 and GPx.

SIGNIFICANCE

Sitagliptin attenuated Cd-induced testicular injury via boosting the autophagy/apoptosis ratio through activation of AMPK/mTOR and Nrf2/HO-1 pathways.

Carvone suppresses oxidative stress and inflammation in the liver of immobilised rats

OBJECTIVE

The investigation of the effect of carvone (a natural monoterpene) on liver damage caused by chronic immobilisation.

METHODS

Male Wistar rats were divided into four groups: control, carvone, stress, and stress-carvone. To induce stress, rats were placed in a restrainer (6 h/21 day) and carvone was treated by gavage at a dose of 20 mg/kg.

RESULTS

Alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase activities were significantly increased in sera of immobilised rats. Chronic immobilisation also increased malondialdehyde levels and decreased reduced glutathione content, as well as increased TNF-α, IL-1β, IL-6, and NF-κB mRNA expression and also led to the infiltration of inflammatory cells in the liver parenchyma. Carvone's 21-day treatment prevented all of these changes in immobilised rats.

CONCLUSION

It is concluded that carvone has effectively prevented chronic immobilisation-induced liver injury, most probably through its antioxidant and anti-inflammatory capabilities.

Antitumor activity of sitagliptin and vitamin B12 on Ehrlich ascites carcinoma solid tumor in mice

This study was carried out to investigate the potential effects of vitamin B12 and sitagliptin, and their possible synergistic effect with doxorubicin (DOX) on the Ehrlich solid tumor model. B12, sitagliptin, and their combination with DOX were administered to tumor-bearing mice for 21 days. Treatment with B12, sitagliptin, as well as their combinations with DOX caused a significant inhibition of tumor growth and increased the survival time. Malondialdehyde levels and the relative expression of tumor necrosis factor-α and nuclear factor kappa B were significantly decreased, whereas the total antioxidant capacity was significantly increased in all treated groups, except the DOX-treated one, when compared with the positive control group. Moreover, increased apoptosis was also observed by increased cleaved caspase-3 immunostaining and histopathological examination. In conclusion, the antitumor activity of B12 and sitagliptin could be attributed to their ability to induce apoptosis and suppress oxidative stress and inflammation.

Hepatoprotective effect of rebamipide against methotrexate-induced hepatic intoxication: role of Nrf2/GSK-3β, NF-κβ-p65/JAK1/STAT3, and PUMA/Bax/Bcl-2 signaling pathways

OBJECTIVES

The fact that methotrexate (MTX) is hepatotoxic is an important reason to limit its clinical use. Rebamipide (REB) has antioxidant and anti-inflammatory properties and is useful for the treatment of gastro-duodenal ulcers. This study investigated the impact and protective mechanisms of REB against MTX-induced hepatotoxicity in rats.

MATERIALS AND METHODS

Animals were divided into four groups of six rats each: a control group, REB group (REB 100 mg/kg/day, orally), MTX control group (20 mg/kg, single i.p.), and MTX + REB group.

RESULTS

The administration of MTX induced marked hepatic injury in the form of hepatocyte inflammatory swelling, degeneration, apoptosis, and focal necrosis. In parallel, our biochemical investigations revealed a marked hepatic dysfunction associated with the disturbance of the oxidant/antioxidant balance in the group treated with only MTX. Moreover, MTX led to the down-regulation of the hepatic Nrf2 and Bcl-2 expressions along with a marked elevation in the hepatic NF-κβ-p65, GSK-3β, JAK1, STAT3, PUMA, and Bax expressions. On the other hand, co-treatment with REB significantly ameliorated the aforementioned histopathological, biochemical, and molecular defects caused by MTX treatment.

CONCLUSION

the outcomes of the present study showed REB's ability to protect from hepatic injury induced by MTX, possibly through its antioxidant, anti-inflammatory, and anti-apoptotic properties. These effects could be attributed to REB's ability to modulate, at least in part, the Nrf2/GSK-3β,NF-κβ-p65/JAK1/STAT3, and PUMA/Bax/Bcl-2signaling pathways.

Sitagliptin and tofacitinib ameliorate adjuvant induced arthritis via modulating the cross talk between JAK/STAT and TLR-4/NF-κB signaling pathways

AIMS

Rheumatoid arthritis is an autoimmune systemic disorder causing pain, swelling, stiffness, and disability in various joints. This work was designed to evaluate the effect of sitagliptin and tofacitinib on Janus kinase (JAK)/signaling transducer and activator of transcription (STAT) and toll like receptor (TLR-4)/nuclear factor kappa B (NF-κB) signaling pathways in adjuvant induced arthritis in rats.

MATERIALS AND METHODS

Severity of arthritis was evaluated and serum was analyzed for inflammatory mediators. The mRNA and protein expression level of the most important members of the two signaling pathways were determined. Lipid profile, transaminases and renal function parameters were assessed.

KEY FINDINGS

Sitagliptin and tofacitinib significantly decreased the level of inflammatory parameters, the mRNA and protein expression level of the members of JAK/STAT and TLR-4/NF-κB pathways with more prominent effect of sitagliptin on TLR-4/NF-κB pathway and more expected obvious effect of tofacitinib on JAK/STAT pathway. The combination offered additional anti-inflammatory effect by inhibiting the cross talk between these pathways as inhibition of NF-κB activation decreased the serum level of IL-6 preventing the activation of STAT-3 in tibiotarsal tissues.

SIGNIFICANCE

The combination of tofacitinib and sitagliptin normalized serum lipids and blood glucose level which could offer protection against cardiovascular diseases and caused partial reversal of serum transaminases and creatinine levels which can protect against tofacitinb's related hepato and nephrotoxicity. We could conclude that the combination of Sitagliptin with tofacitinib can offer synergistic anti-inflammatory effect and more protective action against side effects of tofacitinib.

Zingerone protects liver and kidney tissues by preventing oxidative stress, inflammation, and apoptosis in methotrexate-treated rats

The clinical use of drugs used in the treatment of diseases is limited due to the toxic side effects, and many studies have been conducted to benefit from herbal adjuvant therapies recently to eliminate these effects. In this study, the protective effect of zingerone against liver and kidney damage generated in rats through methotrexate (MTX). Histopathological investigations were performed to determine tissue damage caused by MTX and the healing effect of zingone and liver function markers such as serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and renal function markers such as urea, creatine, and aquaporin-1 (AQP-1) were measured. The effects of MTX and protective properties of zingerone on oxidative stress were investigated through the measurement of malondialdehyde and reduced glutathione (GSH) levels, catalase (CAT), and glutathione peroxidase (GPx) enzyme activities. The anti-inflammatory effect of zingerone was determined by measuring the cytokine levels causing inflammation such as nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), and its effects on apoptosis were determined by immunohistochemical analysis of caspase-3 and B-cell lymphoma-2 (Bcl-2) expression levels. According to the results obtained within the scope of the study, it was determined that zingerone treatment prevented the increase in MTX-induced liver and kidney function markers, showed healing effects on antioxidant parameters degraded in both tissues, and decreased the inflammation parameters. It was determined that it also prevented apoptosis and possessed a protective effect on disrupted tissue architecture by decreasing the increased caspase-3 expression and increasing the decreased Bcl-2 level.

Effects of hydrogen-rich water prepared by alternating-current-electrolysis on antioxidant activity, DNA oxidative injuries, and diabetes-related markers

Hydrogen-rich water is conventionally prepared by direct current-electrolysis, but has been not or scarcely prepared by alternating current (AC)-electrolysis. The AC preparations from tap water for 20-30 minutes exhibit a dissolved hydrogen concentration of 1.55 mg/L, which was close to the theoretical maximum value of 1.6 mg/L. These preparations also displayed an oxidation-reduction potential of -270 mV (tap water: +576 mV) and pH of 7.7-7.8, being closer to physiological values of body fluids than general types of direct current-electrolytic hydrogen-rich water. We examined whether AC-electrolytic hydrogen-water is retained for hydrogen-abundance after boiling or for antioxidant abilities, and whether the oral administration of this water is clinically effective for diabetes and prevention against systemic DNA-oxidative injuries. 5,5-Dimethyl-1-pyrroline-N-oxide spin trapping and electron spin resonance revealed that the hydrogen-rich water generated by AC-electrolysis exhibited hydroxyl-radical-scavenging activities. Laser nanoparticle tracking method revealed that nanoparticle suspensions as abundant as 5.4 × 107/mL were efficiently retained (up to 3.5 × 107/mL) even after boiling for 10 minutes, being thermodynamically contrary to Henry's law. Oral intake of hydrogen-rich water, 1500 mL per day, lasted for 8 weeks in nine people with the diabetes-related serum markers beyond the normal ranges. The subjects exhibited significant tendencies for the decreased fasting blood glucose and fructosamine, and for the increased 1,5-anhydro-D-glucitol, concomitantly with significant decreases in urinary 8-hydroxy-2-deoxyguanosine contents and its rate of generation. Hydrogen-rich water prepared by AC-electrolysis may be effective in improving diverse diabetes-related markers and systemic DNA oxidative injuries through the formation of abundant heat-resistant nanobubbles and the increased hydrogen concentrations. The study protocol was officially approved by the Medical Ethics Committee of the Japanese Center for Anti-Aging Medical Sciences (approval No. 01S02) on September 15, 2009.

Hepatoprotective effect of limonene against chronic immobilization induced liver damage in rats

Prolonged immobilization may impair the physiological functions of various organs of the body, including the liver, brain, and heart. In this study, we investigated the hepatoprotective effect of limonene (a monoterpene) in male rats exposed to chronic immobilization. Rats were exposed to immobilization stress (6 h/21 days) and received limonene (10 mg/kg, oral gavage) during this period. Chronic immobilization increased the levels of liver enzymes alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in serum. Increased levels of malondialdehyde and decreased glutathione content were also observed in the liver tissue of immobilized rats. Expression of TNF-α, IL-1β, IL-6, and NF-κB mRNA was increased, and infiltrated cells were also observed in the liver parenchyma in rats exposed to chronic immobilization. Limonene prevented all these changes in immobilized rats. These results suggest that limonene, due to its antioxidant and anti-inflammatory effects, rescues the liver from damages caused by chronic immobilization.

The hepatoprotective effect of sitagliptin against hepatic ischemia reperfusion-induced injury in rats involves Nrf-2/HO-1 pathway

BACKGROUND

Oxidative stress and inflammation play a key role in the development of hepatic ischemia reperfusion (HIR)-induced injury. Nuclear factor-erythroid 2-related factor-2 (Nrf-2) is a main regulator of numerous genes, encoding cytoprotective molecules including heme oxygenase-1 (HO-1). Sitagliptin (Sit) is an incretin enhancer acting via inhibition of dipeptidyl peptidase-4 (DPP-4) enzyme. This study was undertaken to investigate the ability of Sit to prevent the hepatic pathological changes of HIR induced injury and to modify Nrf-2 and its target HO-1.

METHODS

Pringle's maneuver was used to induce total HIR in adult male rats that were randomly assigned into 4 groups. Group1 (sham-operated control), Group 2 (sham-operated + Sit-control group), Group 3 (HIR non-treated), and Group 4 (HIR + Sit). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities together with hepatic contents of malondialdhyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) and superoxide dismutase (SOD) activity were evaluated. Hepatic tissue mRNA of Nrf-2 and protein content of HO-1 along with histopathological examination and scoring of hepatic injury were performed.

RESULTS

Sit caused a significant reduction in ALT and AST activities together with attenuation of HIR-induced histopathological liver injury. Effect of Sit was associated with decreased hepatic level of MDA and NO with increased GSH level and SOD activity. Non-treated rats with HIR showed an increase in Nrf-2 mRNA expression and HO-1 content in hepatic tissue which was further increased by Sit treatment.

CONCLUSIONS

These results indicate that hepatoprotective activity of Sit against HIR is attributed at least in part to modulation of Nrf-2/ HO-1 signaling pathway.

Sitagliptin protects male albino rats with testicular ischaemia/reperfusion damage: Modulation of VCAM-1 and VEGF-A

Twisting of the spermatic cord is considered a popular problem in the urological field, which may lead to testicular necrosis and male infertility. Sitagliptin, a glucose-lowering agent, proved to have a vindicatory function in myocardial and renal ischaemia/reperfusion (I/R), but its role in testicular I/R has not yet been studied. The current work investigates its capability to recover the testicular I/R injury with shedding more light on the mechanism of its action. Four groups were used: sham, sham pretreated with sitagliptin, I/R and sitagliptin/I/R-pretreated groups. The outcomes proved that I/R significantly decreased the serum testosterone, with a major increase in oxidative, inflammatory and nitrosative stress, along with a reduction in testicular vascular endothelial growth factor-A level with marked germinal cell apoptosis. However, pretreatment with sitagliptin significantly reversed the profound testicular I/R damaging effects, on the basis of its antioxidant, anti-inflammatory and anti-apoptotic activities with the ability of recuperation of the testicular vascularity.

The impact of Crocus sativus stigma against methotrexate-induced liver toxicity in rats

Background

The adverse effects of methotrexate (MTX) mainly hepatotoxicity restrict its clinical use. This study was designed to investigate the protective effects of saffron (Crocus sativus) (CS) extract on MTX-induced hepatotoxicity.

Methods

Twenty-eight male Wistar rats randomly divided into four equal groups. Except for control, all groups received a single intraperitoneal (i.p.) injection of MTX on the 3rd day of study. The CS extract was given (80 mg/kg i.p.) to rats 3 days before MTX and continued for the next 7 days (Pre&Post-CS group) or administrated after MTX injection and lasted for 7 days (Post-CS group). On the 11th day, all rats were sacrificed and their plasma levels of liver enzymes including aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were determined. Also, liver histopathology and hepatic levels of malondialdehyde (MDA), nitric oxide (NO) and super oxidase dismutase (SOD) were evaluated.

Results

The results showed that MTX significantly incremented plasma levels of AST, ALT, ALP and LDH (all p<0.001) and hepatic MDA and NO levels; whereas, decreased SOD activity. Histological alterations such as early fatty changes were evident in the MTX group. Administration of CS extract at both methods could ameliorate liver enzyme elevation, oxidative/nitrosative stresses and morphological alterations of the liver. Pre-and-post treatment with CS extract showed better protective effects than only post-treatment.

Conclusion

The present findings provide showing CS could effectively alleviate MTX-induced hepatotoxicity in rats. Further investigations are recommended to determine the exact mechanisms underlying the hepatoprotective potential of saffron.

Activation of pCREB/Nrf-2 signaling mediates re-positioning of liraglutide as hepato-protective for methotrexate -induced liver injury (MILI)

Methotrexate (MTX) is commonly used to treat several types of cancer and autoimmune diseases. However, there is increasing concern over its organs toxicities particularly liver toxicity. Liraglutide, a glucagon like peptide-1 agonist, possesses antioxidant and anti-inflammatory features. This study aimed to explore the potential protective effect of liraglutide pre-treatment in ameliorating MTX-induced hepatotoxicity and to further investigate the underlying mechanisms. Rats received 1.2 mg/kg liraglutide intraperitoneal twice daily for 7 days before MTX. Results revealed that liraglutide significantly decreased activities of liver enzymes and oxidative stress in hepatocytes. Furthermore, NF-kB expression and related inflammatory markers (TNF-α, COX-2 and IL-6) were reduced in the pre-treatment group of liraglutide. These data validate the advantageous effects of liraglutide in MTX hepatotoxic animals. In addition, liraglutide increased the expression of the antioxidant transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf-2), along with the transcription of downstream phosphorylated cAMP response element-binding protein (pCREB) which increases the activity of Nrf-2. Additionally, caspase-3 expression/activity and BAX/Bcl-2 ratio were decreased following liraglutide pre-treatment. In conclusion, it was confirmed that liraglutide enhanced the antioxidant activity of liver cells by activating the Nrf-2 and pCREB signaling, thereby, reducing liver cell inflammation and apoptosis induced by MTX.

Hydrogen sulfide modulates IL-6/STAT3 pathway and inhibits oxidative stress, inflammation, and apoptosis in rat model of methotrexate hepatotoxicity

Methotrexate (MTX) is a commonly used anticancer and immunosuppressive agent. However, MTX can induce hepatotoxicity due to oxidative stress, inflammation, and apoptosis. Hydrogen sulfide (H₂S), the endogenous gaseous molecule, has antioxidant, anti-inflammatory, and anti-apoptotic effects. The present work explored the probable protective effect of H₂S against MTX hepatotoxicity in rats and also the possible mechanisms underlying this effect. MTX was given at a single intraperitoneal (i.p.) dose of 20 mg/kg. Sodium H₂S (56 µmol /kg/day, i.p.), as H₂S donor, was given for 10 days, starting 6 days before MTX administration. H₂S significantly reduced serum alanine aminotransferase, hepatic malondialdehyde, interleukin 6, nuclear factor κB p65, cytosolic cytochrome c, phosphorylated signal transducer and activator of transcription 3, and Bax/Bcl-2 ratio and significantly increased hepatic total antioxidant capacity and endothelial nitric oxide synthase (eNOS) in rats received MTX. In addition, H₂S minimized the histopathological injury and significantly decreased the expression of STAT3 in liver tissue of MTX-challenged rats. The effects of H₂S were significantly antagonized by administration of glibenclamide as K_ATP channel blocker, Nω-nitro-l-arginine, as eNOS inhibitor, or ruthenium red, as transient receptor potential vanilloid 1 (TRPV1) antagonist. It was concluded that H₂S provided significant hepatoprotection in MTX-challenged rats through its antioxidant, anti-inflammatory, anti-apoptotic effects. These effects are most probably mediated by the ability of H₂S to act as IL-6/STAT3 pathway modulator, K_ATP channel opener, eNOS activator, and TRPV1 agonist.

Ellagic acid as a potential antioxidant, alleviates methotrexate-induced hepatotoxicity in male rats

BACKGROUND

Hepatotoxicity is one of the most life-threatening side-effects of Methotrexate therapy. Former studies highlighted the significance of oxidative stress in promoting Methotrexate-induced hepatotoxicity (MIH). Hence, the current study investigated the protective effect of Ellagic acid (EA), a poly-phenolic antioxidant, against MIH.

METHODS

Twenty-eight male Wistar rats were grouped into four sets: group 1 (control), group 2 (injected intraperitoneally with 20 mg/kg of Methotrexate on the 9th day), group 3 (treated orally with 10 mg/kg/day of EA for 10 days and injected with Methotrexate on the 9th day) and group 4 (treated with EA for 10 days). Subsequently, biochemical and histopathological parameters were evaluated in serum samples and liver tissues.

RESULTS

Methotrexate significantly increased activities of aminotransferases and ALP enzymes as well as levels of oxidative stress parameters in liver tissue. Likewise, Methotrexate decreased hepatic reduced glutathione level and activities of antioxidant enzymes. EA pre-treatment markedly attenuated the activities of aminotransferases and ALP, levels of oxidative stress parameters and augmented activities of antioxidant enzymes. Similarly, the remarkable protective effect of EA on liver has been confirmed by histological examination.

CONCLUSION

In sum, the current study supports the hypothesis that EA may be used as a promising pre-therapy to prevent the MIH.

Pristimerin protects against doxorubicin-induced cardiotoxicity and fibrosis through modulation of Nrf2 and MAPK/NF-kB signaling pathways

Background/purpose

Pristimerin (Pris) is triterpenoid compound with many biological effects. Until now, nothing is known about its effect on doxorubicin (DOX)-induced cardiotoxicity. Hence, this study investigated the impact of Pris on DOX-induced cardiotoxic effects.

Materials and methods

Rats were treated with Pris 1 week before and 2 weeks contaminant with repeated DOX injection. Afterwards, electrocardiography (ECG), biochemical, histopathological, PCR, and Western blot assessments were performed.

Results

Pris effectively alleviated DOX-induced deleterious cardiac damage. It inhibited DOX-induced ECG abnormities as well as DOX-induced elevation of serum indices of cardiotoxicity. The histopathological cardiac lesions and fibrosis were remarkably improved in Pris-treated animals. Pris reduced hydroxyproline content and attenuated the mRNA and protein expression of the pro-fibrogenic genes. The antioxidant activity of Pris was prominent through the amelioration of oxidative stress parameters and enhancement of antioxidants. Furthermore, Pris enhanced the activation of nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway as it increased the mRNA and protein expression of Nrf2 and Nrf2-dependent antioxidant genes (GCL, NQO1, HO-1). Additionally, the anti-inflammatory effect of Pris was obvious through the inhibition of mitogen activated protein kinase (MAPK)/nuclear factor kappa-B (NF-kB) signaling and subsequent inhibition of inflammatory mediators.

Conclusion

This study provides evidence of the cardioprotective activity of Pris which is related to the modulation of Nrf2 and MAPK/NF-kB signaling pathways.

Modulating impacts of quercetin/sitagliptin combination on streptozotocin-induced diabetes mellitus in rats

BACKGROUND

Since many diabetic patients require combination therapy, the use of herbal remedies with anti-diabetic activity represents a vital option in diabetes mellitus (DM) management. It has been reported that quercetin has hypoglycemic alongside anti-inflammatory and antioxidant activities.

AIM

The present study aimed to investigate the effectiveness of combining quercetin with sitagliptin; a selective dipeptidyl peptidase-IV (DPP-IV) inhibitor, in the management of streptozotocin (STZ)-induced diabetic rats.

METHODS

DM was induced by a single injection of STZ (45 mg/kg, i.p.) in male adult albino Wistar rats. Diabetic rats were orally treated with sitagliptin (70 mg/kg), quercetin (50 mg/kg) or their combination daily for three consecutive weeks. Serum levels of glucose, C-peptide, total cholesterol, triglycerides, malondialdehyde (MDA), superoxide dismutase, (SOD), reduced glutathione (GSH), tumor necrosis factor alpha, (TNF-α), nuclear factor kappa-B, (NF-κB) and adiponectin were estimated. In addition, histopathological, morphometrical and immunohistochemical examinations of pancreatic tissues were conducted.

RESULTS

The combined administration of quercetin and sitagliptin normalized serum C-peptide, MDA, and significantly increased SOD, GSH and decreased NF-κB more than sitagliptin alone. Moreover, this combination normalized Islet number, β-cells' number, area and perimeter alongside restoring the immunostaining intensity of β-cells.

CONCLUSION

Our results suggest the use of quercetin/sitagliptin combination for treating DM based on the observed improvements in glycemic control, metabolic profile, oxidative and inflammatory status, islet structure as well as β-cells function compared with either treatment alone.

Neuroprotective influence of sitagliptin against cisplatin-induced neurotoxicity, biochemical and behavioral alterations in Wistar rats

Cisplatin has been extensively used as a chemotherapeutic agent since around 40 years, though its usage is limited due to severe adverse effects like neurotoxicity that might be because of oxidative stress. Hence, the present study was planned to investigate the possible protective role of sitagliptin against cisplatin-associated neurotoxic, biochemical, and behavioral alterations in male Wistar rats. Sitagliptin is a dipeptidyl peptidase-4 inhibitor that shows dual effects by improving the control on metabolism as well as decreasing the debility in cognitive function that is associated with increased insulin sensitivity and antioxidant property. For the in vitro assay, cultured rat pheochromocytoma (PC12) cells were exposed to different concentrations (10, 20, and 50 mM) of sitagliptin for 24 h. Cisplatin at 5 mM concentrations was added and cell viability was assessed using MTT assay. For in vivo study, animals were divided into four groups. Group I (Vehicle control): animals were administered 0.9% (w/v) of normal saline (1 mL/100 g; p.o.). Group II (Cisplatin): animals were treated with cisplatin (2 mg/kg; i.p.). Group III (Cisplatin + sitagliptin): animals were administered cisplatin along with sitagliptin. Group IV (Sitagliptin): animals were given sitagliptin (10 mg/kg; p.o.). All the treatments were administered for 8 weeks. On last day of treatment, behavioral evaluations including locomotor and rotarod studies were performed. In addition, several antioxidant enzymes were also estimated from cerebellum tissues; such as levels of thiobarbituric acid reactive substance (TBARS) were determined as a marker of lipid peroxidation, reduced glutathione (GSH) and catalase (CAT) were also estimated. Histological study of cerebellum tissue was also performed after performing the behavioral study. Exposure to cisplatin decreased cell viability in PC12 cells which were significantly increased by co-treatment with sitagliptin. In in vivo study, cisplatin significantly elevated the level of TBARS and reduced the level of antioxidant enzymes such as GSH and CAT which were significantly restored in sitagliptin + cisplatin group of rats. In addition, cisplatin impaired performance on the locomotor and rotarod activities, whereas sitagliptin significantly improved the performance of both activities. These results suggested the neuroprotective influence of sitagliptin by protecting cerebellum part of brain against cisplatin-induced toxicity.

Sitagliptin attenuates intestinal ischemia/reperfusion injury via cAMP/PKA, PI3K/Akt pathway in a glucagon-like peptide 1 receptor-dependent manner

AIMS

This study investigated the effect of sitagliptin prophylactic treatment on intestinal I/R rat model and explored the possible underlying mechanism.

MAIN METHODS

Forty-five male Sprague-Dawley rats were randomly assigned to 3 groups: Sham group (operation without clamping), I/R group (operation with clamping) and sitagliptin pretreated group (300 mg/kg/day; p.o.) for 2 weeks before I/R insult. Intestinal I/R was performed by clamping the superior mesenteric artery for 30 min, followed by 60 min reperfusion after removal of clamping. At the end of the experimental period, all rats were sacrificed for histopathological, biochemical, PCR and western blot assessment.

KEY FINDINGS

Pretreatment with sitagliptin remarkably alleviated the pathological changes induced by I/R in the jejunum, suppressed upregulated NF-κB, TNF-α, IL-1βand MPO caused by I/R. Moreover, sitagliptin decreased the Bax/Bcl-2 ratio and accordingly suppressed apoptotic tissue damage as reflected by a caspase-3 level reduction in rat intestine subjected to I/R injury. Interestingly, sitagliptin could obviously increase the active GLP-1 level and GLP-1 receptor mRNA expression in the jejunum of I/R rats. This was associated with the augmentation of the cAMP level and enhancement of PKA activity. Simultaneously, sitagliptin treatment was able to increase the protein expression levels of phosphorylated PI3K and Akt.

SIGNIFICANCE

Sitagliptin has shown protective effects against intestinal I/R injury in rats through reduction of intestinal inflammation and apoptosis. The molecular mechanisms may be partially correlated with activation of cAMP/PKA and PI3K/Akt signaling pathway by the GLP-1/GLP-1 receptor.

Dipeptidyl Peptidase-4 Is a Pro-Recovery Mediator During Acute Hepatotoxic Damage and Mirrors Severe Shifts in Kupffer Cells

Dipeptidyl peptidase-4 (DPP-4 or clusters of differentiation [CD]26) is a multifunctional molecule with established roles in metabolism. Pharmacologic inhibition of DPP-4 is widely used to improve glycemic control through regulation of the incretin effect. Colaterally, CD26/DPP-4 inhibition appears to be beneficial in many inflammatory conditions, namely in delaying progression of liver pathology. Nevertheless, the exact implications of CD26/DPP-4 enzymatic activity in liver dysfunction remain unclear. In this work, we investigated the involvement of CD26/DPP-4 in experimental mouse models of induced hepatocyte damage that severely impact Kupffer cell (KC) populations. Liver dysfunction was evaluated in CD26 knockout (KO) and B6 wild-type mice during acute liver damage induced by acetaminophen, chronic liver damage induced by carbon tetrachloride, and KC-depleting treatment with clodronate-loaded liposomes. We found that necrosis resolution after hepatotoxic injury was delayed in CD26KO mice and in B6 mice treated with the CD26/DPP-4 inhibitor sitagliptin, suggesting that DPP-4 enzymatic activity plays a role in recovering from acute liver damage. Interestingly, the severe KC population reduction in acute and chronic liver injury was concomitant with increased CD26/DPP-4 serum levels. Remarkably, both chronic liver damage and noninflammatory depletion of KCs by clodronate liposomes were marked by oscillation in CD26/DPP-4 serum activity that mirrored the kinetics of liver KC depletion/recovery. Conclusion:CD26/DPP-4 enzymatic activity contributes to necrosis resolution during recovery from acute liver injury. Serum CD26/DPP-4 is elevated when severe perturbations are imposed on KC populations, regardless of patent liver damage. We propose that serum CD26/DPP-4 is a potential systemic surrogate marker of severe impairments in the KC population imposed by clinical and subclinical liver conditions.

Hepatoprotective effect of rhein against methotrexate-induced liver toxicity

The purpose of this study was to investigate the protective effect of rhein, a major metabolite of diacerein, on methotrexate (MTX)-induced hepatotoxicity and clarify the pharmacological mechanism. Rhein significantly reduced the elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) caused by MTX in rat serum and improved liver morphological damage induced by MTX. Moreover, rhein increased the cell survival rate and reduced the number of apoptosis cells in MTX-treated normal human hepatocyte (L02 cells). Rhein treatment in rats up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2), B-cell lymphoma-2 (Bcl-2), heme oxygenase 1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC), and down-regulated Bcl-2 associated x (Bax) in mRNA and protein levels. Furthermore, rhein treatment further decreased protein expression of nuclear factor-kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) and cysteine aspartic acid specific protease 3 (Caspase-3), increased protein expression of B-cell lymphoma-extra large (Bcl-xl), and reduced mRNA expression of Bcl-2 homologous antagonist/killer (Bak) in MTX-treated rat liver in vivo. However, the protein expression changes of Nrf2, HO-1, GCLC, Bcl-2, Bcl-xl and Bax could be abrogated by Nrf2 antagonist brusatol. In addition, protective effect of rhein against MTX-mediated liver damage could also be suppressed by Nrf2 siRNA in L02 cells. Taken together, these findings suggested that rhein ameliorated liver damage mediated by MTX through acting on Nrf2-HO-1 pathway. NF-κB, TNF-α, Caspase-3 and Bcl-2 family were also participated in the protection. As effectively hepatoprotective ability of rhein, it would raise an important issue for patients orally receiving MTX treatment together with diacerein/rhein.

Acute Liver Injury Induced by Sitagliptin: Report of Two Cases and Review of Literature

We present two cases of acute liver injury associated with sitagliptin. The first case was a 58-year-old male with a history of poorly controlled type 2 diabetes mellitus and hyperlipidemia. Sitagliptin was added for better control of diabetes. After initiation of sitagliptin, the patient's serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels increased gradually over a period of six months. The second case was a 44-year-old female with type 2 diabetes mellitus, and she experienced a more than ten-fold elevation in ALT and AST levels after starting sitagliptin therapy. Both patients did not have any history of alcohol abuse, acetaminophen use, or chronic liver disease. In the literature review, the reported magnitude of liver enzyme derangement with sitagliptin is generally mild and transient (two-fold upper limit of normal). We believed that the acute derangement of ALT and AST in our patients was due to sitagliptin since the ALT and AST normalized shortly after sitagliptin was discontinued and remained at baseline after resuming all other medications. Further research is needed to understand the mechanism of dipeptidyl peptidase 4 (DPP-4) inhibitors associated liver injury.

Alpha lipoic acid exerts antioxidant effect via Nrf2/HO-1 pathway activation and suppresses hepatic stellate cells activation induced by methotrexate in rats

Hepatic injury is a major side effect associated with methotrexate (MTX) therapy resulting from inflammatory reactions and oxidative stress induction. Therefore, liver fibrosis incidence is augmented with long-term MTX therapy. Alpha lipoic acid (ALA) is a naturally occurring compound with potent antioxidant activity. This study explored the hepatoprotective mechanisms of ALA against MTX-induced hepatic injury in rats. Hepatic injury was induced in MTX group by 20 mg/kg body weight ip. injection of MTX. ALA group was pretreated with ALA 60 mmol/kg body weight ip. for five days followed by a single dose of MTX in the sixth day. Blood samples and liver tissues were then obtained to assess several biochemical parameters as serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), reduced glutathione (GSH), total antioxidant capacity (TAC) and lipid peroxidation. Nuclear factor E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway was studied by determining the extent of mRNA Nrf2 expression and the level of HO-1. Hepatic stellate cells (HSCs) activation was evaluated by estimating the expression of α-smooth muscle actin (α-SMA) and hydroxyproline content. Also, tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and caspase-3 were assessed by ELISA in addition to histopathological examination of liver samples. Results showed that ALA pretreatment improved liver function since serum ALT, AST and ALP levels were reduced. Additionally, ALA restored GSH and TAC levels when compared to MTX group and decreased lipid peroxidation. ALA exerted its antioxidant effect via Nrf2/HO-1 pathway as well as it showed anti-inflammatory and antiapoptotic effects by reducing TNF-α, iNOS, COX-2 and caspase-3 levels in liver tissue homogenate. Finally, ALA suppressed HSCs activation by decreasing α-SMA expression and hydroxyproline content in liver. It was concluded that ALA has hepatoprotective effects against MTX-induced hepatic injury mediated by Nrf2/HO-1 pathway as well as anti-inflammatory and antiapoptotic properties.

TAT-mediated intracellular delivery of carboxypeptidase G2 protects against methotrexate-induced cell death in HepG2 cells

Side effects of methotrexate (MTX) especially hepatotoxicity limits clinical applications of this anticancer agent. Carboxypeptidase G2 (CPG2) is administrated for the treatment of elevated plasma concentrations of MTX. In this study, we have investigated the intracellular delivery of CPG2 fused to the transactivator transduction domain (TAT) and its protective effects against MTX-induced cell death of HepG2 cells. We have observed that both native and denatured forms of the enzyme transduced into the HepG2 cells efficiently in a concentration and time-dependent manner. The denatured protein transduced with higher efficiency than the native form and was functional inside the cells. MTX exposure significantly decreased HepG2 cell viability in a dose- and time-dependent manner. The cell viability after 24 and 48 h of incubation with 100 μM MTX was reduced to 44.37% and 17.69%, respectively. In cells pretreated with native and denatured TAT-CPG2 protein the cell viability was 98.63% and 86.31% after 24 and 48 h, respectively. Treatment with MTX increased the number of apoptotic HepG2 cells to 90.23% after 48 h. However, the apoptosis percentage in cells pretreated with native and denatured TAT-CPG2 was 21.49% and 22.28%, respectively. Our results showed that TAT-CPG2 significantly prevents MTX-induced oxidative stress by decreasing the formation of ROS and increasing the content of glutathione (GSH) and catalase activity. Our finding indicates that both native and denatured TAT-CPG2 strongly protect HepG2 cells against MTX-induced oxidative stress and apoptosis. Hence, intracellular delivery of CPG2 might provide a new therapeutic strategy for protecting against MTX mediated cytotoxicity.

Ameliorative potential of sitagliptin and/or resveratrol on experimentally-induced clear cell renal cell carcinoma

The aim of this study was to assess the effect of sitagliptin with or without resveratrol on carcinogen-induced clear cell renal cell carcinoma. Sixty male Wistar rats were divided into 6 equal groups as follows: control; clear cell renal cell carcinoma group; clear cell renal cell carcinoma+sitagliptin group; clear cell renal cell carcinoma+resveratrol group; clear cell renal cell carcinoma+carboxymethyl cellulose group and clear cell renal cell carcinoma+sitagliptin+resveratrol group. Blood urea, serum creatinine, creatinine clearance, urinary N-acetyl beta-d-glucosaminidase (NAG), gamma glutamyl transpeptidase (GGT) and urinary albumin excretion rate (UAER) were determined. Renal tissue antioxidant enzymes, lactate dehydrogenase (LDH), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase-1 (HO-1), transforming growth factor beta-1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and signal transducers and activators of transcription-3 (STAT3) were determined. Parts of the kidneys were subjected to histopathological and immunohistochemical examination for nuclear factor kappa B (p65). Sitagliptin and/or resveratrol induced significant improvement of the renal functions with significant increase in tissue antioxidant defenses and Nrf2/HO-1 content associated with significant decrease in tissue LDH, TGF-β1, TNF-α, IL-6 and STAT3 and alleviated the histopathological and immunohistochemical changes compared to the untreated clear cell renal cell carcinoma group. These effects were significant in sitagliptin/resveratrol combination group compared to the use of each of these drugs alone. In conclusion, sitagliptin/resveratrol combination might represent a beneficial therapeutic modality for amelioration of experimentally-induced clear cell renal cell carcinoma.