Introduction including Alzheimer’s disease [17], Parkinson’s disease
Brain Research 885 2000 62–69 www.elsevier.com locate bres
Research report
Dietary restriction attenuates the neuronal loss, induction of heme oxygenase-1 and blood–brain barrier breakdown induced by impaired
oxidative metabolism
1
Noel Y. Calingasan , Gary E. Gibson
Weill Medical College of Cornell University , Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA
Accepted 29 August 2000
Abstract
Experimental thiamine deficiency TD is a model of impaired oxidative metabolism associated with region-selective neuronal loss in the brain. Oxidative stress is a prominent feature of TD neuropathology, as evidenced by the accumulation of heme oxygenase-1 HO-1,
ferritin, reactive iron and superoxide dismutase in microglia, nitrotyrosine and 4-hydroxynonenal in neurons, as well as induction of endothelial nitric oxide synthase within the vulnerable areas. Dietary restriction DR reduces oxidative stress in several organ systems
including the brain. DR increases lifespan and reduces neurodegeneration in a variety of models of neuronal injury. The possibility that DR can protect vulnerable neurons against TD-induced oxidative insults has not been tested. The current studies tested whether
approximately 3 months of DR 60 of ad libitum intake altered the response to TD. Six month-old ad libitum-fed or dietary restricted C57BL 6 mice received a thiamine-deficient diet either ad libitum, or under a DR regimen respectively for eleven days. The TD mice also
received daily injections of the thiamine antagonist pyrithiamine. Control ad libitum-fed or DR mice received an unlimited amount, or 60 of ad libitum intake, respectively, of thiamine-supplemented diet. As in past studies, TD produced region-selective neuronal loss
260, HO-1 induction, and IgG extravasation in the thalamus of ad libitum-fed mice. DR attenuated the TD-induced neuronal loss 230, HO-1 induction and IgG extravasation in the thalamus. These studies suggest that oxidative damage is critical to the
pathogenesis of TD, and that DR modulates the extent of free radical damage in the brain. Thus, TD is an important model for studying the relationship between aging, oxidative stress and nutrition.
2000 Elsevier Science B.V. All rights reserved.
Theme : Disorders of the nervous system
Topic : Degenerative disease: other
Keywords : Dietary restriction; Heme oxygenase-1; Neurodegeneration; Oxidative stress; Thiamine
1. Introduction including Alzheimer’s disease [17], Parkinson’s disease
[28], and Wernicke–Korsakoff syndrome [5]. As in these Experimental thiamine deficiency TD models the
human diseases, oxidative stress is a prominent feature of molecular and cellular mechanisms by which chronic
TD-induced neurodegeneration in animals. TD induces aberrations in oxidative metabolism associated with well-
indicators of oxidative stress including heme oxygenase-1, defined biochemical lesions i.e., reduction of thiamine-
HO-1 [10], superoxide dismutase [33], ferritin, and dependent enzyme activities lead to selective neurode-
reactive iron [9] in microglia. TD also increases the generation in brain. Reductions in thiamine-dependent
nitration product of peroxynitrite, nitrotyrosine [9] and the enzymes also occur in many neurodegenerative disorders
lipid peroxidation product, 4-hydroxynonenal [10] in neu- rons within the vulnerable areas. Our recent studies
suggest that early stages of TD induce intercellular adhe-
Corresponding author. Tel.: 11-914-597-2291; fax: 11-914-597-
sion molecule-1 ICAM-1 and endothelial nitric oxide
2757.
synthase eNOS, indicating that oxidative stress to mi-
E-mail address : ggibsonmed.cornell.edu G.E. Gibson.
1
crovessels in the thalamus is a critical initial event in the
Present address: Otsuka America Pharmaceutical, Inc., 9900 Medical Center Drive, Rockville, MD 20850, USA.
pathogenesis of TD [8]. Furthermore, TD elevates the
0006-8993 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 0 0 6 - 8 9 9 3 0 0 0 2 9 3 3 - 4
N .Y. Calingasan, G.E. Gibson Brain Research 885 2000 62 –69
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concentration of reactive oxygen species in the thalamus 0.1 ml of saline 10 g body weight; Sigma, St. Louis, MO.
[22]. Thus, although the mechanism underlying the region- Dietary restricted controls DR C; n55 received a
specific neurodegeneration during TD is unknown, evi- thiamine-supplemented diet and intraperitoneal saline in-
dence for the role of oxidative stress is mounting. jection 0.1 ml 10 g body weight. The thiamine-deficient
Dietary restriction DR is a well-established means of and thiamine-supplemented diets for the DR TD and DR
prolonging the lifespan of mammals [3,34]. DR may act by C groups, respectively, were fed at 60 of the ad libitum
modulating or reducing oxidative stress in several organ intake.
systems [20]. This hypothesis is further strengthened by For the ad libitum group, TD was induced in 5 animals
recent investigations suggesting that DR increases the AL TD as in the DR group except that the thiamine-
resistance of neurons to a variety of oxidative insults. For deficient diet was not restricted. Ad libitum controls AL
example, DR protects neurons against MPTP-induced C; n55 received an unlimited amount of thiamine-sup-
toxicity [14], excitotoxicity, and metabolic injury [4]. DR plemented diet, and intraperitoneal saline injection.
also protects hippocampal neurons in mice against the deleterious presenilin-1 mutation that is linked to early
2.3. Tissue preparation and immunocytochemistry onset of Alzheimer’s disease [36].
If increased oxidative damage is a key underlying Mice were euthanized with halothane after 11 days of
mechanism for the sensitivity of selective neurons and the TD, and perfused transcardially with 0.9 NaCl solution
blood–brain barrier to TD, then it would be predicted that followed by 4 paraformaldehyde in 0.1 M sodium
the dietary restricted, thiamine-deficient mice would be phosphate buffer PB; pH 7.4. Brains were removed and
less sensitive than the ad libitum fed, thiamine-deficient sectioned 35 mm thick.
group. The current studies tested whether DR affords Free-floating sections to be analyzed for neuronal loss
protection against selective neurodegeneration and blood– were immunostained with an antibody against an excellent
brain barrier breakdown during TD. neuronal marker, neuron-specific nuclear protein, NeuN
[29]. This method eliminates the problem of distinguishing between small interneurons and glial cells, which is