Article

Role of oxidative stress on beta-amyloid neurotoxicity elicited during impairment of energy metabolism in the hippocampus: protection by antioxidants.

Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México AP 70-253, México DF 04510, México.
Experimental Neurology (Impact Factor: 4.65). 09/2006; 200(2):496-508. DOI: 10.1016/j.expneurol.2006.02.126
Source: PubMed

ABSTRACT Age-associated oxidative stress has been implicated in neuronal damage linked with Alzheimer's disease (AD). In addition to the role of beta-amyloid peptide (Abeta) in the pathogenesis of AD, reduced glucose oxidative metabolism and decreased mitochondrial activity have been suggested as associated factors. However, the relationship between Abeta toxicity, metabolic impairment, and oxidative stress is far from being understood. In vivo neurotoxicity of Abeta25-35 peptide has been conflicting. However, in previous studies, we have shown that Abeta25-35 consistently induces synaptic toxicity and neuronal death in the hippocampus in vivo, when administered during moderate glycolytic or mitochondrial inhibition. In the present study, we have investigated whether enhancement of Abeta neurotoxicity during these conditions involves oxidative stress. Results show increased lipoperoxidation (LPO) when Abeta is administered in the hippocampus of rats previously treated with the glycolysis inhibitor, iodoacetate. Neuronal damage and LPO are efficiently prevented by vitamin E, while the spin trapper, alpha-phenyl-N-tert-butyl nitrone, shows partial protection. Abeta stimulates LPO in synaptosomes, but toxicity is only observed in the presence of metabolic inhibitors. Damage and LPO are efficiently prevented by vitamin E. The present results suggest an interaction between oxidative stress and metabolic impairment in the Abeta neurotoxic cascade.

0 Bookmarks
 · 
115 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Alzheimer's disease (AD) is the most common form of dementia and is characterized by the presence of senile plaques and neurofibrillary tangles, along with synaptic loss. The underlying mechanisms of AD are not clarified yet, but oxidative stress and mitochondrial dysfunction are important factors. Overactivation of poly(adenosine diphosphate ribose) polymerase-1 (PARP-1) enzyme has been known to cause neuroinflammation and cell death in neurodegenerative processes. The aim of the present study was to investigate the protective effects of the PARP-1 inhibitors, 3-aminobenzamide (3-AB) and nicotinamide (NA), against amyloid β peptide (1–42) (Aβ(1–42))-induced oxidative damage and mitochondrial reduction capacity on isolated synaptosomes. Rats were injected intraperitoneally with 3-AB (30–100 mg kg−1), NA (100–500 mg kg−1) or with saline for 7 days. Synaptosomes were incubated with 10–30 μM Aβ(1–42) or saline for 6 h at 37 °C. Ex vivo Aβ(1–42) treatment significantly induced oxidative stress and mitochondrial dysfunction in synaptosomes of the saline group, while synaptosomes of 3-AB and NA groups showed significant decreases in lipid peroxidation, reactive oxygen species production and protein oxidation. Moreover, both NA and 3-AB were able to improve the mitochondrial reduction capacity against Aβ(1–42). These data suggest that NA and 3-AB may have protective effects in neurodegenerative processes because of the reduced levels of oxidative stress and the improvement of mitochondrial function. Copyright © 2014 John Wiley & Sons, Ltd.
    Cell Biochemistry and Function 08/2014; · 1.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Alzheimer's disease (AD) results in memory impairment and neuronal cell death in the brain. Previous studies demonstrated that intracerebroventricular administration of streptozotocin (STZ) induces pathological and behavioral alterations similar to those observed in AD. Agmatine (Agm) has been shown to exert neuroprotective effects in central nervous system disorders. In this study, we investigated whether Agm treatment could attenuate apoptosis and improve cognitive decline in a STZ-induced Alzheimer rat model. We studied the effect of Agm on AD pathology using a STZ-induced Alzheimer rat model. For each experiment, rats were given anesthesia (chloral hydrate 300 mg/kg, ip), followed by a single injection of STZ (1.5 mg/kg) bilaterally into each lateral ventricle (5 μL/ventricle). Rats were injected with Agm (100 mg/kg) daily up to two weeks from the surgery day. Agm suppressed the accumulation of amyloid beta and enhanced insulin signal transduction in STZ-induced Alzheimer rats [experimetal control (EC) group]. Upon evaluation of cognitive function by Morris water maze testing, significant improvement of learning and memory dysfunction in the STZ-Agm group was observed compared with the EC group. Western blot results revealed significant attenuation of the protein expressions of cleaved caspase-3 and Bax, as well as increases in the protein expressions of Bcl2, PI3K, Nrf2, and γ-glutamyl cysteine synthetase, in the STZ-Agm group. Our results showed that Agm is involved in the activation of antioxidant signaling pathways and activation of insulin signal transduction. Accordingly, Agm may be a promising therapeutic agent for improving cognitive decline and attenuating apoptosis in AD.
    Yonsei medical journal 05/2014; 55(3):689-99. · 0.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Vitamin E (vit-E) is a lipophilic antioxidant, and its anti-inflammatory activity is still not full characterized. Thus, our goal was to investigate the anti-inflammatory effect of repeated vit-E treatment in the arthritis induced by the intraplantar injection of complete Freund's adjuvant (CFA). We observed an increase in arthritis scores, interleukin-1β and H2O2 levels, neutrophil and macrophage infiltration, thermal hyperalgesia, mechanical allodynia, and loss of function induced by intraplantar CFA injection. These effects were unaltered after 1 day, partially reversed after 3 days, and inhibited after 9 days after vit-E treatment. Furthermore, the concentration of vit-E was reduced and that of tumor necrosis factor-alpha was increased in the CFA-injected paw. Both effects were reversed from 1 to 9 days after vit-E treatment. However, vit-E treatment did not alter CFA-induced edema at any time. Thus, vit-E treatment produced an anti-inflammatory effect of slow onset in CFA, which demonstrates a disease-modifying drug profile.
    Inflammation 08/2014; · 2.46 Impact Factor