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Type: Artigo de periódico
Title: Polyphenol-enriched Cocoa Protects The Diabetic Retina From Glial Reaction Through The Sirtuin Pathway
Author: Duarte D.A.
Rosales M.A.
Papadimitriou A.
Silva K.C.
Amancio V.H.O.
Mendonca J.N.
Lopes N.P.
Lopes de Faria J.B.
Lopes de Faria J.M.
Abstract: Cocoa is rich in flavonoids, which are potent antioxidants with established benefits for cardiovascular health but unproven effects on neurodegeneration. Sirtuins (SIRTs), which make up a family of deacetylases, are thought to be sensitive to oxidation. In this study, the possible protective effects of cocoa in the diabetic retina were assessed. Rat Mu¨ller cells (rMCs) exposed to normal or high glucose (HG) or H2O2 were submitted to cocoa treatment in the presence or absence of SIRT-1 inhibitor and small interfering RNA The experimental animal study was conducted in streptozotocin-induced diabetic rats randomized to receive low-, intermediate-, or high-polyphenol cocoa treatments via daily gavage for 16weeks (i.e., 0.12, 2.9 or 22.9mg/kg/day of polyphenols). The rMCs exposed to HG or H2O2 exhibited increased glial fibrillary acidic protein (GFAP) and acetyl-RelA/p65 and decreased SIRT1 activity/expression. These effects were cancelled out by cocoa, which decreased reactive oxygen species production and PARP-1 activity, augmented the intracellular pool of NAD+, and improved SIRT1 activity. The rat diabetic retinas displayed the early markers of retinopathy accompanied by markedly impaired electroretinogram. The presence of diabetes activated PARP-1 and lowered NAD+ levels, resulting in SIRT1 impairment. This augmented acetyl RelA/p65 had the effect of up-regulated GFAP. Oral administration of polyphenol cocoa restored the above alterations in a dose-dependent manner. This study reveals that cocoa enriched with polyphenol improves the retinal SIRT-1 pathway, thereby protecting the retina from diabetic milieu insult.
Editor: Elsevier Inc.
Rights: fechado
Identifier DOI: 10.1016/j.jnutbio.2014.09.003
Date Issue: 2014
Appears in Collections:Unicamp - Artigos e Outros Documentos

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