Phytic acid attenuates acetaminophen-induced hepatotoxicity via modulating iron-mediated oxidative stress and SIRT-1 expression in mice.

Introduction: Administration of high doses of acetaminophen (APAP) results in liver injury. Oxidative stress and iron overload play roles in the pathogenesis of APAP-induced hepatotoxicity. The present study assessed the potential hepatoprotective effects of phytic acid (PA), a natural antioxidant and iron chelator, on APAP-induced hepatotoxicity and the possible underlying mechanism through its effects on CYP2E1 gene expression, iron homeostasis, oxidative stress, and SIRT-1 expression levels. Methods: Twenty-four adult male albino mice were used in this study. Mice were divided into four groups (six mice in each group): control, APAP-treated, PA-treated and APAP + PA-treated groups. Liver function tests, serum and liver tissue iron load were evaluated in all the study groups. Hepatic tissue homogenates were used to detect oxidative stress markers, including malondialdehyde (MDA) and reduced glutathione (GSH). Histological hepatic evaluation and immunohistochemistry of SIRT-1 were performed. Quantitative real-time PCR was used for the assessment of CYP2E1 and SIRT-1 gene expressions. APAP-induced biochemical and structural hepatic changes were reported. Results: PA administration showed beneficial effects on APAP-induced hepatotoxicity through improvements in liver functions, decreased CYP2E1 gene expression, decreased serum and liver iron load, decreased MDA, increased GSH, increased SIRT-1 expression level and improvement in hepatic architecture. Conclusion: Conclusively, PA can be considered a potential compound that can attenuate acetaminophen-induced hepatotoxicity through its role as an iron chelator and antioxidant, as well as the up-regulation of SIRT-1 and down-regulation of CYP2E1.

Effects of Stevia rebaudiana Bertoni extracts in the rat model of epilepsy induced by pentylenetetrazol: Sirt-1, at the crossroads between inflammation and apoptosis.

The current study investigated the effects of stevia extracts on a PTZ-induced epileptic rat model and its potential mechanism. Thirty male Sprague-Dawley rats were equally subdivided into 3 groups; (1) normal control (NC) group, (2) PTZ-group: received PTZ (50 mg/kg, i.p. every other day) for 2 weeks, and (3) PTZ+ Stevia group: received PTZ and stevia (200 mg/kg orally daily) for 4 weeks (2 weeks before the start of PTZ treatment and 2 weeks with PTZ administration). The first jerk latency and the seizure score were assessed in rats. Also, brain tissue samples were collected by the end of the experiment, and oxidative stress markers (catalase, MDA, and total antioxidant capacity (TAC)) were measured by biochemical analysis in hippocampal brain homogenates. Also, in the hippocampus, the expression of IL6 and Bcl-2 at the mRNA level and expression of Sirt-1, P53, caspase-3, GFAP, and NF-kB in CA3 hippocampal region by immunohistochemistry was investigated. PTZ substantially increased the seizure score and decreased the seizure latency. Also, PTZ significantly increased MDA, GFAP, IL-6, NF-kB, caspase-3, and p53 and significantly reduced Sirt-1, TAC, and Bcl-2 in hippocampal tissues compared to the control group (p < 0.01). However, Stevia Rebaudiana Bertoni (Stevia R.) significantly attenuated the PTZ-induced seizures, improved oxidative stress markers, downregulated GFAP, IL-6, NF-kB, caspase-3, and p53, and upregulated Sirt-1 and Bcl-2 in the CA3 hippocampal region (p < 0.01). In conclusion, Stevia R. exhibits neuroprotective and antiepileptic actions in PTZ-induced epilepsy due to its antioxidant, anti-apoptotic, and anti-inflammatory effects. Additionally, the Sirt-1 pathway might be involved in the antiepileptic and neuroprotective effects of stevia in PTZ-kindled epileptic rat model.

Effects of long-acting erythropoietin analog darbepoetin-α on adriamycin-induced chronic nephropathy.

OBJECTIVES: To study the effects of darbepoetin-α (DPO-α) (erythropoietin analog) on adriamycin (ADR)-induced chronic nephropathy in rats. METHODS: Sixty-nine male Sprague-Dawley rats divided into 3 groups (23 rats each): negative control group: normal rats received saline as a vehicle; positive control (ADR) group: rats received 2 iv injection of ADR via penile vein at 14-day interval without treatment; and DPO-α group: as ADR group but rats received sc DPO-α (0.3 µg/kg bw) once weekly for 12 weeks. By the end of experiment hemoglobin (Hb) content, serum creatinine, BUN, albumin, triglycerides and cholesterol, urinary protein excretion and kidney injury molecule-1 (KIM-1). GSH, malondialdehyde, caspase-3 expression histopathological and electron microscopic examinations for kidney tissues were done. RESULTS: DPO-α significantly improved the animal survival rate and body weight, Hb, serum BUN, triglycerides, cholesterol, and albumin and urinary protein excretion and KIM-1 in urine. Also, administration of DPO-α improved the morphological damage in glomeruli and renal tubules as well as caspase-3 expression and markers of oxidative stress in kidney tissues. CONCLUSION: Administration of DPO-α alleviates ADR nephropathy and this might due to improvement of Hb content, hyperlipidemia, enhancement of endogenous antioxidants, reduction of apoptosis and tubulointerstitial injury and maintaining the integrity of glomerular membrane.

Effects of combined erythropoietin and epidermal growth factor on renal ischaemia/reperfusion injury: a randomized experimental controlled study.

OBJECTIVE: To investigate effects of combination of erythropoietin (EPO) and epidermal growth factor (EGF) on renal ischaemia and on reactive oxygen species in a rat model. MATERIALS AND METHODS: In all, 90 male Sprague-Dawley rats were allocated into five groups of 18, designated: Sham; treated with right nephrectomy only; Control, subjected to left renal ischaemia for 45 min with no treatment; EPO-treated, as the control but with EPO pretreatment; EGF-treated, as the control but with EGF pretreatment; EPO + EGF-treated, as the control but with EPO and EGF pretreatment. Renal function, histopathology and malondialdehyde (MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) levels in kidneys were assessed at 1, 2 and 7 days after ischaemia. RESULTS: All rats except the controls had a significant improvement in serum creatinine, creatinine clearance and fractional excretion of Na(+) ; all three were significantly better in EPO + EGF group than in all other groups Histopathological examination showed marked structural damage in control rats. The tubular damage was least in the EPO + EGF group. The control group had a significant increase in MDA level and a significant decrease in SOD and GSH, while the EPO + EGF group had a marked significant reduction in MDA and increase in GSH and SOD. CONCLUSION: The protection against ischaemia/reperfusion injury might be maximal when EPO and EGF are administered concomitantly, and their protective effect might be partly due to their antioxidant effects.

Original Article: Investigation of Bcl-2 and PCNA in Hepatocellular Carcinoma: Relation to Chronic HCV.

BACKGROUND AND OBJECTIVE: Bcl-2 family members can be functionally divided into anti-apoptotic and proapoptotic groups. The balance between these two groups may determine the fate of tumor cells. In hepatocellular carcinoma (HCC), this balance is often tilted towards the anti-apoptotic members in tumor cells, leading to resistance to cell death and rapid proliferation. MATERIAL AND METHODS: In the current study, we investigated Bcl-2 and proliferating cell nuclear antigen (PCNA) immunohistochemically, using specific monoclonal antibodies in liver tissues obtained from two patient groups. The first group included fifty patients infected with hepatitis C virus (HCV) without hepatocellular carcinoma, the other group included twenty five HCVinfected patients but with confirmed HCC. Serum Bcl-2 was assayed using enzyme immunoassay. RESULTS: Results showed serum Bcl-2 was elevated in 82% versus 100% in HCC-free and HCC patients, respectively. Moreover, cytoplasmic staining of Bcl-2 was found in only 16% of chronic HCV patients without HCC, versus 8% in HCC patients. On the other hand, nuclear staining of PCNA was detected in 100% of HCC patients, but in none of the HCV patients without HCC. CONCLUSION: The results collectively suggest that in HCV-infected patients with and without HCC, apoptosis is dysregulated and proliferation activity perturbed. There may be prognostic and/or diagnostic potential in estimating Bcl-2 and PCNA proteins in these patient groups. KEY WORDS: Bcl-2 - PCNA - Apoptosis - HCC - HCV.