Oxidative stress is regarded as a mediator of nerve cell death in several neurodegenerative disorders, such as Parkinson's disease. Sesamin, a lignan mainly found in sesame oil, is currently under study for its anti-oxidative and possible neuroprotective properties. We used 1-methyl-4-phenyl-pyridine (MPP+) ion, the active metabolite of the potent parkinsonism-causing toxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine, to produce oxidative stress and neurodegeneration in neuronal PC12 cells, which express dopamine, as well as neurofilaments. Our results show that picomolar doses of sesamin protected neuronal PC12 cells from MPP+-induced cellular death, as revealed by colorimetric measurements and production of reactive oxygen species. We also demonstrated that sesamin acted by rescuing tyrosine hydroxylase levels from MPP+-induced depletion. Sesamin, however, did not modulate dopamine transporter levels, and estrogen receptor-alpha and -beta protein expression. By examining several parameters of cell distress, we found that sesamin also elicited a strong increase in superoxide dismutase activity as well as protein expression and decreased catalase activity and the MPP+ stimulated inducible nitric oxide synthase protein expression, in neuronal PC12 cells. Finally, sesamin possessed significant anti-inflammatory properties, as disclosed by its potential to reduce MPP+-induced interleukin-6 mRNA levels in microglia. From these studies, we determined the importance of the lignan sesamin as a neuroprotective molecule and its possible role in complementary and/or preventive therapies of neurodegenerative diseases.

Vicky Lahaie-Collins

Julie Bournival

Marilyn Plouffe

Julie Carange

Maria-Grazia Martinoli

Sesamin Modulates Tyrosine Hydroxylase, Superoxide Dismutase, Catalase, Inducible No Synthase and Interleukin-6 Expression in Dopaminergic Cells Under Mpp+-Induced Oxidative Stress

Previously, we have shown that the window of opportunity for nicotinamide (NAM) therapy (50 mg/kg) following cortical contusion injuries (CCI) extended to 4–8 hrs post-CCI when administered over a six day post-CCI interval. The purpose of the present study was to determine if a more chronic NAM treatment protocol administered following CCI would extend the current window of opportunity for effective treatment onset. Groups of rats received either unilateral CCI's or sham procedures. Initiation of NAM therapy (50 mg/kg, ip) began at either 15-min, 4-hrs, 8-hrs or 24-hrs post-injury. All groups received daily systemic treatments for 12 days post-CCI at 24 hr intervals. Behavioral assessments were conducted for 28 days post injury and included: vibrissae forelimb placing, bilateral tactile adhesive removal, forelimb asymmetry task and locomotor placing testing. Behavioral analysis on both the tactile removal and locomotor placing tests showed that all NAM-treated groups facilitated recovery of function compared to saline treatment. However, on the vibrissae-forelimb placing and forelimb asymmetry tests only the 4-hr and 8-hr NAM-treated groups were significantly different from the saline-treated group. The lesion analysis showed that treatment with NAM out to 8 hrs post-CCI significantly reduced the size of the injury cavity. The window of opportunity for NAM treatment is task-dependent and in some situations can extend to 24 hrs post-CCI. These results suggest that a long term treatment regimen of 50 mg/kg of NAM starting at the clinically relevant time points may prove efficacious in human TBI.

Michael R Hoane

Jeremy L Pierce

Nicholas A. Kaufman

Jason E. Beare

Variation  in Chronic Nicotinamide Treatment after Traumatic Brain Injury Can Alter Components of Functional Recovery Independent of Histological Damage

Arsenic is a naturally occurring element that is ubiquitously present in the environment. High concentration of naturally occurring arsenic in drinking water is a major health problem in different parts of the world. Despite arsenic being a health hazard and a well documented carcinogen, no safe, effective and specific preventive or therapeutic measures are available. Among various recent strategies adopted, administration of an antioxidant has been reported to be the most effective. The present study was designed to evaluate the therapeutic efficacy of monoisoamyl dimercaptosuccinic acid (MiADMSA), administered either individually or in combination with taurine post chronic arsenic exposure in rats. Arsenic exposed male rats (25 ppm, sodium arsenite in drinking water for 24 weeks) were treated with taurine (100 mg/kg, i.p., once daily), monoisoamyl dimercaptosuccinic acid (MiADMSA) (50 mg/kg, oral, once daily) either individually or in combination for 5 consecutive days. Biochemical variables indicative of oxidative stress along-with arsenic concentration in blood, liver and kidney were measured. Arsenic exposure significantly reduced blood δ-aminolevulinic acid dehydratase (ALAD) activity, a key enzyme involved in the heme biosynthesis and enhanced zinc protoporphyrin (ZPP) level. Clinical hematological variables like white blood cells (WBC), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC) showed significant decrease with a significant elevation in platelet (PLT) count. These changes were accompanied by significant decrease in superoxide dismutase (SOD) activity and increased catalase activity. Arsenic exposure caused a significant decrease in hepatic and renal glutathione (GSH) level and an increase in oxidized glutathione (GSSG). These biochemical changes were correlated with an increased uptake of arsenic in blood, liver and kidney. Administration of taurine significantly reduced hepatic oxidative stress however co-administration of a higher dose of taurine (100 mg/kg) and MiADMSA provided more pronounced effects in improving the antioxidant status of liver and kidney and reducing body arsenic burden compared to the individual treatment of MiADMSA or taurine. The results suggest that in order to achieve better effects of chelation therapy, co-administration of taurine with MiADMSA might be preferred.

Swaran J. S. Flora

Swapnila Chouhan

Gurusamy M. Kannan

Megha Mittal

Harimohan Swarnkar

Combined Administration of Taurine and Monoisoamyl Dmsa Protects Arsenic Induced Oxidative Injury in Rats

We have developed and evaluated an in vitro culture method for assessing ischemic injury in primary mouse renal tubular epithelial cells (RTEC) in which to explore the pathobiology underlying acute kidney injury. RTEC were predominately of proximal tubule origin which is most susceptible to ischemic injury as compared to other nephron segments. Oxidative stress was induced by chemically depleting ATP using Antimycin A and 2-Deoxy-D-Glucose and by exposing cells to a 1% oxygen environment. Necrotic injury was assessed by measuring LDH released into culture supernatants. Optimal dose and time of exposure to each injury agent was determined for induction of mild, moderate and severe ischemic injury defined as LDH release of &#x02264;20%, 21&#x02013;49% and &#x02265;50% above baseline respectively. Antimycin A and 2-Deoxy-D-Glucose produced a progressive increase in LDH release which was time dependent but chemical concentration independent. A 1% oxygen environment also induced cell injury over time but only if glucose was absent from the culture media. Antimycin A was most effective at inducing oxidative stress causing a mean LDH release of 61% at 48 hr compared to 19% and 50% LDH release induced by 2-Deoxy-D-Glucose and by exposure to 1% oxygen respectively at the same 48 hour time point.The cell culture method described provides several advantages including the use of serum free media and the ability to grow primary cells without matrix support. The LDH assay for injury assessment is reproducible, cost effective, objective and minimizes background cell death. A simple method for the culture and injury of primary mouse renal tubular epithelial cells has thereby been established and provides a useful tool for future investigations of ischemic kidney injury.

Anne C. Breggia

Jonathan Himmelfarb

Primary Mouse Renal Tubular Epithelial Cells Have Variable Injury Tolerance to Ischemic and Chemical Mediators of Oxidative Stress

Spermatogenesis is a highly complicated process in which functional spermatozoa (haploid, 1n) are generated from primitive mitotic spermatogonia (diploid, 2n). This process involves the differentiation and transformation of several types of germ cells as spermatocytes and spermatids undergo meiosis and differentiation. Due to its sophistication and complexity, testis possesses intrinsic mechanisms to modulate and regulate different stages of germ cell development under the intimate and indirect cooperation with Sertoli and Leydig cells, respectively. Furthermore, developing germ cells must translocate from the basal to the apical (adluminal) compartment of the seminiferous epithelium. Thus, extensive junction restructuring must occur to assist germ cell movement. Within the seminiferous tubules, three principal types of junctions are found namely anchoring junctions, tight junctions, and gap junctions. Other less studied junctions are desmosome-like junctions and hemidesmosome junctions. With these varieties of junction types, testes are using different regulators to monitor junction turnover. Among the uncountable junction modulators, nitric oxide (NO) is a prominent candidate due to its versatility and extensive downstream network. NO is synthesized by nitric oxide synthase (NOS). Three traditional NOS, specified as endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS), and one testis-specific nNOS (TnNOS) are found in the testis. For these, eNOS and iNOS were recently shown to have putative junction regulation properties. More important, these two NOSs likely rely on the downstream soluble guanylyl cyclase/cGMP/protein kinase G signaling pathway to regulate the structural components at the tight junctions and adherens junctions in the testes. Apart from the involvement in junction regulation, NOS/NO also participates in controlling the levels of cytokines and hormones in the testes. On the other hand, NO is playing a unique role in modulating germ cell viability and development, and indirectly acting on some aspects of male infertility and testicular pathological conditions. Thus, NOS/NO bears an irreplaceable role in maintaining the homeostasis of the microenvironment in the seminiferous epithelium via its different downstream signaling pathways.

Nikki P. Y. Lee

C. Yan Cheng

Nitric Oxide and Cyclic Nucleotides: Their Roles in Junction Dynamics and Spermatogenesis

R. John Aitken

Shaun D. Roman

Antioxidant Systems and Oxidative Stress in the Testes

For a number of disease entities, oxidative stress becomes a significant factor in the etiology and progression of cell dysfunction and injury. Therapeutic strategies that can identify novel signal transduction pathways to ameliorate the toxic effects of oxidative stress may lead to new avenues of treatment for a spectrum of disorders that include diabetes, Alzheimer's disease, Parkinson's disease and immune system dysfunction. In this respect, metabotropic glutamate receptors (mGluRs) may offer exciting prospects for several disorders since these receptors can limit or prevent apoptotic cell injury as well as impact upon cellular development and function. Yet the role of mGluRs is complex in nature and may require specific mGluR modulation for a particular disease entity to maximize clinical efficacy and limit potential disability. Here we discuss the potential clinical translation of mGluRs and highlight the role of novel signal transduction pathways in the metabotropic glutamate system that may be vital for the clinical utility of mGluRs.

Kenneth Maiese

Zhao Zhong Chong

Yan Chen Shang

Jinling Hou

Therapeutic Promise and Principles: Metabotropic Glutamate Receptors

About this journal

Oxidative Medicine and Cellular Longevity publishes research involving cellular and molecular mechanisms of oxidative stress in the nervous system and related organ systems in relation to aging, immune function, vascular biology, and metabolism.

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Chief Editor&nbsp;Dr Vasquez-Vivar has experience in free radical and redox biology research including the discovery of the role of tetrahydrobiopterin in the regulation of superoxide generation by endothelial and neuronal nitric oxide synthase.

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Oxidative Medicine and Cellular Longevity - Table of contents 2008

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Oxidative Medicine and Cellular Longevity publishes research involving cellular and molecular mechanisms of oxidative stress in the nervous system and related organ systems in relation to aging, immune function, vascular biology, and metabolism.

Oxidative Medicine and Cellular Longevity