Erythropoietin Suppresses the Hepatic Fibrosis Caused by Thioacetamide: Role of the PI3K/Akt and TLR4 Signaling Pathways

Erythropoietin (EPO) is recognized for its function in erythropoiesis; however, its potential antifibrotic effect against liver fibrosis remains unknown. This study examined whether EPO affects thioacetamide (TAA)-induced liver fibrosis by concentrating on the Toll-like receptor 4 (TLR4) cascade and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway as possible pathways. Male Wistar rats were randomized into four groups, which included: the negative control group, the TAA group (intraperitoneal; TAA 100 mg/kg three times per week for 2 weeks), and EPO-treated groups (150 and 300 IU/kg, i.p.) for 2 weeks after TAA injections. EPO attenuated hepatic fibrosis in a dosage-dependent way, as manifested by the diminution in serum alanine aminotransferase and aspartate aminotransferase activities, as well as the increase in albumin level. EPO inhibited the increase in tissue levels of tumor necrosis factors-α, interleukin-1β, transforming growth factor-β1, and TLR4 and raised tissue levels of PI3K and p-PI3K. EPO antioxidant properties were demonstrated by restoring hepatic glutathione and superoxide dismutase by preventing the accumulation of hepatic malondialdehyde. Further, EPO increased the protein expression of PI3K and Akt and decreased TLR4 protein expression. Immunohistochemically, EPO treatment altered tissue histology and downregulated mitogen-activated protein kinase protein expression. Overall, the research suggested that EPO could prevent TAA-induced hepatic fibrosis through upregulating the PI3K/Akt signaling cascade and downregulation the TLR4 downstream axis.

Ginkgo biloba extract (EGb 761) mitigates methotrexate-induced testicular insult in rats: Targeting oxidative stress, energy deficit and spermatogenesis

Methotrexate (MTX) is commonly used as a therapeutic agent in the treatment of malignancies and autoimmune disorders. Risk of subsequent infertility following MTX administration has been reported as a significant side effect due to testicular toxicity. The aim of the study was to evaluate the modulatory effects of Ginkgo biloba (standardized extract, EGb 761) on MTX-induced testicular oxidative stress, energy deficits and spermatogenic status in rats. All groups received intraperitoneal injection of MTX (0.5 mg/kg) twice weekly for four weeks except the control group that received the corresponding vehicles. Other groups received oral EGb761, at doses 25, 50 or 100 mg/kg/day, for four weeks, concurrently with MTX. Blood and semen sampling followed by testis dissection were performed 24 h after last EGb 761 treatment. Semen was examined for sperm progressive motility, percent of normal spermatozoa and sperm cell concentration as well as seminal plasma essential and non-essential amino acids. Serum LH, FSH and testosterone were detected as well as testicular MDA, GSH, GSSG, TNF-α, IL-1β, IL-6, NF-κB and the nuclear, cytoplasmic and mRNA expression levels of Nrf-2 besides the testicular cell energy; AMP, ADP and ATP. Histopathological studies of interstitial fibrosis and the severity of germ cell degeneration were also conducted. MTX induced significant decline in sperm quality along with decreased essential and non-essential amino acids in seminal plasma. MTX reduced serum FSH, LH and testosterone as well as testicular ATP, GSH and Nrf2, while increased levels of testicular ADP, AMP, MDA, GSSG and TNF-α. Results were confirmed by prominent interstitial fibrosis and severe germ cell degeneration in MTX group. Concurrent treatment with EGb 761 alleviated MTX-induced testicular insult evidenced by amelioration of oxidative stress biomarkers, energy functions, seminal sperms abnormalities and spermatogenesis status. The present study suggests a beneficial role of EGb 761 in MTX-induced testicular injury and subsequent distortion of spermatogenesis.

Thioacetamide-induced acute hepatic encephalopathy: central vs peripheral effect of Allicin

Hepatic encephalopathy (HE) is a debilitating and life-threatening disease. Results from acute or chronic liver failure and is characterized by abnormal cerebral and neurological alterations. This study aimed at investigating the effect of allicin, the major functional component in freshly crushed garlic extract, on thioacetamide (TAA)-induced HE in rats. Induction of HE by a single dose of TAA (300 mg/kg; I.P.) was associated with a marked elevation in the serum levels of alanine aminotransferase, aspartate aminotransferase, bilirubin, albumin, total protein, blood urea nitrogen and serum ammonia besides reduction in the serum level of albumin. Moreover, it was accompanied with an increase in the hepatic and brain levels of inflammatory mediators; TNF-α and IL-1β as well as elevation of the hepatic and brain levels of oxidative stress biomarkers; reduced glutathione and lipid peroxidation evidenced by malondialdeyde. Oral administration of allicin (50, 100 and 200 mg/kg; P.O.) for 6 days prior to TAA injection restored the serum liver function, hepatic and brain levels of inflammatory mediators as well as oxidative stress biomarkers in a dose-dependent manner. From our results, it can be concluded that allicin has a protective effect on TAA-induced HE in rats in a dose-dependent manner due to its powerful antioxidant and anti-inflammatory properties.

Rosuvastatin and simvastatin attenuate cisplatin-induced cardiotoxicity via disruption of endoplasmic reticulum stress-mediated apoptotic death in rats: targeting ER-Chaperone GRP78 and Calpain-1 pathways

Cisplatin (CP) is a powerful antineoplastic chemotherapeutic agent with broad-spectrum properties. Acute and cumulative cardiotoxicity are major limiting factors for CP therapy. Various pathogenic pathways have been suggested to CP-induced cardiotoxicity; oxidative damage, ER stress, and programmed cell death/apoptosis. The present study aimed to assess the signaling mechanisms related to the advantageous effects of rosuvastatin (RSV) and simvastatin (SMV) against CP-related cardiac ER stress dependent apoptotic death in rats. Acute cardiotoxicity was induced by a single dose of CP (10 mg/kg, i.p.) on the 10th day of the experiment. RSV (10 mg/ kg/day) and SMV (10 mg/kg/day) were orally administered for 15 days. CP-treated rats showed significant alterations in electrocardiographic recordings and elevation in serum cardiac function biomarkers; troponin T content, lactate dehydrogenase and creatine kinase-MB levels as well as boost in the cardiac oxidative stress biomarkers. In addition, CP exposure resulted in GRP78 induction; an ER stress and elevation marker at calpain-1 content as well as activation of activated caspase-3 (ACASP3) and caspase-12 were reflected on CP-triggered apoptosis evidenced by elevation in the Bax/Bcl-2 ratio. However, RSV and SMV administration mitigate those adverse CP effects. Statins administration prominently alleviated CP-induced cardiac abnormalities exerting improvement in the ECG pattern and cardiac enzyme biomarkers. Interestingly, statins; RSV and SMV, disrupted CP-induced ER stress and the consequent apoptotic cell death evidenced by downregulation of ER-chaperone GRP78, calpain-1, ACASP3 and caspase-12 as well as decline in the Bax/Bcl-2 ratio. From all the previous findings, it can be suggested that statins namely; RSV and SMV, play protective role against CP-induced cardiac injury by regulating ER stress-mediated apoptotic pathways.

Beneficial effects of benfotiamine, a NADPH oxidase inhibitor, in isoproterenol-induced myocardial infarction in rats

BACKGROUND

Acute myocardial infarction (AMI) remains the most common cause of morbidity and mortality worldwide. The present study was directed to investigate the beneficial effects of benfotiamine pre- and post-treatments in isoproterenol (ISO)-induced MI in rats.

METHODS

Myocardial heart damage was induced by subcutaneous injection of ISO (150 mg/kg) once daily for two consecutive days. Benfotiamine (100 mg/kg/day) was given orally for two weeks before or after ISO treatment.

RESULTS

ISO administration revealed significant changes in electrocardiographic recordings, elevation of levels of cardiac enzymes; creatinine kinase (CK-MB) and troponin-I (cTn-I), and perturbation of markers of oxidative stress; nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and markers of inflammation; protein kinase C (PKC), nuclear factor-kappa B (NF-κB) and metalloproteinase-9 (MMP-9). The apoptotic markers (caspase-8 and p53) were also significantly elevated in ISO groups in addition to histological alterations. Groups treated with benfotiamine pre- and post-ISO administration showed significantly decreased cardiac enzymes levels and improved oxidative stress, inflammatory and apoptotic markers compared to the ISO groups.

CONCLUSION

The current study highlights the potential role of benfotiamine as a promising agent for prophylactic and therapeutic interventions in myocardial damage in several cardiovascular disorders via NADPH oxidase inhibition.

Neuroprotective effect of Crocus sativus against cerebral ischemia in rats

The present study aimed to investigate the role of vascular endothelial growth factor (VEGF) in the neuroprotective effect of Crocus sativus (saffron) against cerebral ischemia/reperfusion injury (I/R) in rats. Four groups of a total forty I/R rats with 60-min occlusion followed by 48 h reperfusion or sham surgery were used. The sham and left-brain I/R control groups where treated with normal saline. The rats of the other two groups received saffron extract (100 or 200 mg/kg, ip, respectively) for 3 successive weeks prior to left-brain I/R. Other four doses of saffron extract were received by the rats of the last 2 groups 60 min prior to operation, during the surgery, and on days 1 and 2 following reperfusion. I/R group showed marked neurobehavioral, neurochemical and histopathological alterations. The results revealed a significant reduction in neurological deficit scores in the saffron-treated rats at both doses. Saffron significantly attenuated lipid peroxidation, decreased NO and brain natriuretic peptide (BNP) contents in I/R-brain tissue. On the other hand, saffron reversed the depletion of GSH in the injured brain. Moreover, saffron treatment evidently reduced apoptosis as revealed by a decrease in caspase-3 and Bax protein expression with a marked decrease in the apoptotic neuronal cells compared to I/R group. In addition, saffron administration effectively upregulated the expression of VEGF in I/R-brain tissue. In conclusion, saffron treatment offers significant neuroprotection against I/R damage possibly through diminishing oxidative stress and apoptosis and enhancement of VEGF.

Ficus deltoidea extract down-regulates protein tyrosine phosphatase 1B expression in a rat model of type 2 diabetes mellitus: a new insight into its antidiabetic mechanism

Ficus deltoidea var. deltoidea Jack (FD) is a well-known plant used in Malay folklore medicine to lower blood glucose in diabetic patients. For further research of the antihyperglycemic mechanisms, the protein tyrosine phosphatase 1B (PTP1B)-inhibitory effect of FD was analysed both in vitro and in vivo. To optimise a method for FD extraction, water, 50, 70, 80, 90 and 95 % ethanol extracts were prepared and determined for their total phenolic and triterpene contents, and PTP1B-inhibition capacity. Among the tested extracts, 70 % ethanol FD extract showed a significant PTP1B inhibition (92·0 % inhibition at 200 µg/ml) and high phenolic and triterpene contents. A bioassay-guided fractionation of the 70 % ethanol extract led to the isolation of a new triterpene (3β,11β-dihydroxyolean-12-en-23-oic acid; F3) along with six known compounds. In vivo, 4 weeks' administration of 70 % ethanol FD extract (125, 250 and 500 mg/kg/d) to streptozotocin-nicotinamide-induced type 2 diabetic rats reversed the abnormal changes of blood glucose, insulin, total Hb, GLUT2, lipid profile, and oxidative stress in liver and pancreas. Moreover, FD reduced the mRNA expression of the key gluconeogenic enzymes (phosphoenolpyruvate carboxykinase and glucose 6-phosphatase) and restored insulin receptor and GLUT2 encoding gene (Slc2a2) expression. In addition, FD significantly down-regulated the hepatic PTP1B gene expression. These results revealed that FD could potentially improve insulin sensitivity, suppress hepatic glucose output and enhance glucose uptake in type 2 diabetes mellitus through down-regulation of PTP1B. Together, our findings give scientific evidence for the traditional use of FD as an antidiabetic agent.

Regulation of PKB/Akt-pathway in the chemopreventive effect of lactoferrin against diethylnitrosamine-induced hepatocarcinogenesis in rats

BACKGROUND

Abnormal activation of protein kinase B (PKB) is associated with many cancers. This makes inhibition of PKB signaling pathway a promising strategy for cancer therapy. Lactoferrin (Lf) has been reported for its inhibition of tumor growth and metastasis, however, the mechanism is not completely understood. Its anti-hepatocarcinogenic activity has not taken the deserved recognition despite the additional advantages of Lf as an antiviral against hepatitis C virus, the main cause of hepatocellular carcinoma (HCC), and as a targeting ligand for delivering chemotherapeutics to hepatoma cells.

METHODS

This study evaluated the anti-hepatocarcinogenic effect of Lf, and the role of PKB in this effect using diethylnitrosamine (DENA)-induced HCC rat model, and a primary cell culture prepared from the induced hepatic lesions (DENA-HCC cell culture).

RESULTS

Up-regulation of activated PKB in the hepatocytes of rats with DENA-induced HCC was observed, as measured biochemically in the liver homogenate, and localized immunohistochemically. This was accompanied by increment of hepatocytes proliferation, and expression of vascular endothelial growth factor and endothelial nitric oxide synthase. Involvement of PKB in DENA-induced HCC was confirmed by the observed decrease in cell proliferation in DENA-HCC cell culture that was treated with PKB inhibitor. In Lf-treated rats, a dose-dependent chemopreventive effect was observed, with decreased expression and activation of PKB, amelioration of the other DENA-induced alterations, and stimulation of apoptosis. In vitro, Lf blocked PKB activator-induced cell proliferation.

CONCLUSION

These findings support the chemopreventive activity of Lf against HCC, and suggest regulation of PKB-pathway as a potential mechanism underlying this effect.

The Carcinogenic Agent Diethylnitrosamine Induces Early Oxidative Stress, Inflammation and Proliferation in Rat Liver, Stomach and Colon: Protective Effect of Ginger Extract

Background: Diethylnitrosamine (DENA), a well-known dietary carcinogen, related to cancer initiation of various organs. The present study investigated the deleterious mechanisms involved in the early destructive changes of DENA in different organs namely, liver, stomach and colon and the potential protective effect of GE against these mechanisms. Methods: Adult male albino rats were assigned into four groups. A normal control group received the vehicle, another group was injected with a single necrogenic dose of DENA (200 mg/kg, i.p) on day 21. Two groups received oral GE (108 or 216 mg/kg) daily for 28 days. Sera, liver, stomach and colon were obtained 7 days after DENA injection. Serum aspartate transaminase and alanine transaminase were detected as well as reduced glutathione (GSH), malondialdehyde, nitric oxide metabolites, interleukin 1β, tumor necrosis factor (TNF-α), alpha-fetoprotein (AFP) and nuclear factorerythroid 2-related factor2 (Nrf2) in liver, stomach and colon. Histopathological studies and immunohistochemical examination of cyclooxygenase-2 (COX2) were conducted. Results: DENA induced elevation in liver function enzymes with significant increase in oxidation and inflammation biomarkers and AFP while decreased levels of Nrf2 in liver, stomach and colon were detected. Histologically, DENA showed degenerative changes in hepatocytes and inflammatory foci. Inflammatory foci displayed increased expression of COX2 in immunohistochemical staining. GE-pretreatment improved liver function and restored normal GSH with significant mitigation of oxidative stress and inflammatory biomarkers compared to DENA-treated group. AFP was reduced by GE in both doses, while Nrf2 increased significantly. Histology and immunostaining of hepatic COX-2 were remarkably improved in GE-treated groups in a dose dependent manner. Conclusion: GE exerted a potential anti-proliferative activity against DENA in liver, stomach and colon via Nrf2 activation, whilst suppression of oxidation and inflammation.

Genistein Ameliorates Cyclophosphamide - Induced Hepatotoxicity by Modulation of Oxidative Stress and Inflammatory Mediators

AIM:

The present study investigated the protective effect of the phytoestrogen, genistein (GEN), against (CP)-induced acute hepatotoxicity in rats.

MATERIAL AND METHODS:

Male adult rats were randomly assigned into five groups. Normal control group received the vehicles; CP group received a single dose of CP (200 mg/kg, i.p). The other three groups received subcutaneous GEN at doses of 0.5, 1 and 2 mg/kg/day, respectively, for 15 consecutive days prior CP injection. Sera and liver tissues were collected forty-eight hours after CP injection for assessment of liver function enzymes (ALT and AST) in rat sera, the hepatic oxidative/nitrosative biomarkers (GSH, MDA and NOx), hepatic interleukin-1β, and myeloperoxidase activity. Immunohistochemistry of cyclooxygenase-2 and histopathological examination of liver tissues were also conducted.

RESULTS:

The CP-induced acute liver damage was evidenced by elevated serum ALT and AST accompanied by increased hepatic oxidative stress and inflammatory biomarkers. Immunohistochemical outcomes revealed hepatic cyclooxygenase-2 expression in CP group with distortion of liver architecture. GEN-pretreatment significantly ameliorated the deterioration of liver function and exerted significant anti-oxidant and anti-inflammatory activity with a marked decline in hepatic cyclooxygenase-2 expression in a dose dependent-manner.

CONCLUSION:

The present study demonstrated that the antioxidant and anti-inflammatory activities of GEN might contribute to its protective effects against CP-induced liver damage.