Omega-3 deficiency and neurodegeneration in the substantia nigra: Involvement of increased nitric oxide production and reduced BDNF expression Henriqueta Dias Cardoso a,1 , Eraldo Fonseca dos Santos Junior a,1 , David Filipe de Santana a , Catarina Gonçalves-Pimentel a , Monara Kaélle Angelim a , Alinny R. Isaac a , Cláudia Jacques Lagranha b , Rubem Carlos Araújo Guedes c , Eduardo Isidoro Beltrão d , Edgar Morya e , Marcelo Cairrão Araújo Rodrigues a , Belmira Lara da Silveira Andrade-da-Costa a, ⁎ a Departamento de Fisiologia e Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Recife, PE, Brazil b Núcleo de Educação Física e Ciências do Esporte, Centro Acadêmico de Vitória da Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brazil c Departamento de Nutrição, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, Recife, PE, Brazil d Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Recife, PE, Brazil e Instituto Internacional de Neurociência de Natal Edmond e Lily Safra, Natal, RN, Brazil abstract article info Article history: Received 28 June 2013 Received in revised form 1 December 2013 Accepted 16 December 2013 Available online 20 December 2013 Keywords: Brain-derived neurotrophic factor Lipoperoxidation Docosahexaenoic acid Dopamine Oxidative stress Striatum Background: Our previous study demonstrated that essential fatty acid (EFA) dietary restriction over two gener- ations induced midbrain dopaminergic cell loss and oxidative stress in the substantia nigra (SN) but not in the striatum of young rats. In the present study we hypothesized that omega-3 deficiency until adulthood would re- duce striatum's resilience, increase nitric oxide (NO) levels and the number of BDNF-expressing neurons, both potential mechanisms involved in SN neurodegeneration. Methods: Second generation rats were raised from gestation on control or EFA-restricted diets until young or adulthood. Lipoperoxidation, NO content, total superoxide dismutase (t-SOD) and catalase enzymatic activities were assessed in the SN and striatum. The number of tyrosine hydroxylase (TH)- and BDNF-expressing neurons was analyzed in the SN. Results: Increased NO levels were observed in the striatum of both young and adult EFA-deficient animals but not in the SN, despite a similar omega-3 depletion (~65%) in these regions. Increased lipoperoxidation and decreased catalase activity were found in both regions, while lower tSOD activity was observed only in the striatum. Fewer TH- (~40%) and BDNF-positive cells (~20%) were detected at the SN compared to the control. Conclusion: The present findings demonstrate a differential effect of omega-3 deficiency on NO production in the rat's nigrostriatal system. Prolonging omega-3 depletion until adulthood impaired striatum's anti-oxidant re- sources and BDNF distribution in the SN, worsening dopaminergic cell degeneration. General significance: Omega-3 deficiency can reduce the nigrostriatal system's ability to maintain homeostasis under oxidative conditions, which may enhance the risk of Parkinson's disease. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The vulnerability of nigrostriatal dopaminergic neurons to lesions has been a matter of discussion and investigation in early and recent studies, especially due to the relevance of these cells in the etiology of Parkinson's disease [1,2]. It is well established that under physiological conditions, the substantia nigra (SN) has unique biochemical features which leads to a higher vulnerability to oxidative stress (OS) when com- pared to other brain regions [3]. Moreover, inflammation, excitotoxicity and metabolic aspects specific to dopaminergic cells have also been cited as potential cellular mechanisms underlying degeneration of these cells under certain pathological conditions [2]. The SN exhibits a high concentration of microglia [4] and the over- activation of these cells can result in the release of cytokines and free radicals such as superoxide radicals and nitric oxide (NO) [5,6]. These bioactive molecules released from microglia have been thought to contribute to SN dopaminergic cell death induced by mitochondrial dys- function [7] or by lipopolysaccharide-induced inflammation [8]. An intrinsic neuronal population containing nitric oxide synthase (NOS) and nitrergic afferent neurons from the pedunculopontine teg- mental nucleus (PPTg) is also present in the SN [9]. The potential Biochimica et Biophysica Acta 1840 (2014) 1902–1912 ⁎ Corresponding author at: Departamento de. Fisiologia e Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego 1235, Cidade Universitária, Recife, Pernambuco CEP 50670-901, Brazil. Tel.: +55 81 21268530; fax: +55 81 21268976. E-mail addresses: bl@ufpe.br, belmira@gmail.com (B.L.S. Andrade-da-Costa). 1 Contributed equally to this work. 0304-4165/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.bbagen.2013.12.023 Contents lists available at ScienceDirect Biochimica et Biophysica Acta journal homepage: www.elsevier.com/locate/bbagen