Redox status, inflammation, necroptosis and inflammasome as indispensable contributors to high fat diet (HFD)-induced neurodegeneration; Effect of N-acetylcysteine (NAC)

Abstract

Adequate dietary intake has a crucial effect on brain health. High fat diet (HFD) rich in saturated fatty acids is linked to obesity and its complications as neurodegeneration via inducing oxidative stress and inflammation. The present study aimed to evaluate the effect of HFD on cerebral cortex in addition to shedding the light on the modulatory role of N-acetylcytsteine (NAC) and its possible underlying biochemical and molecular mechanisms. Twenty eight male Wistar rats were equally and randomly divided into four groups. Group III, and group IV were fed on HFD (45% kcal from fat) for 10 weeks. Group II and group IV were treated with NAC in a dose of 150 mg/kg body weight via intraperitoneal route. Body weight, blood glucose, serum insulin, insulin resistance index, cerebral cortex redox and inflammatory status were evaluated. Cerebral cortex receptor-interacting serine/threonine-protein kinase3 (RIPK3), mixed-lineage kinase domain-like protein (MLKL), nod like receptor protein 3 (NLRP3), interleukin (IL)-18 levels were determined by immunoassay. In addition, apoptosis-associated speck-like proteins (ASC) expression by real-time PCR; inducible nitric oxide synthase (iNOS), glial fibrillary activating protein (GFAP) and matrix metalloproteinase-9 (MMP-9) expression by immunohistochemistry were evaluated. NAC supplementation protected against HFD-induced gain of weights, hyperglycemia, and insulin resistance. Furthermore, NAC improved redox and inflammatory status; decreased levels of RIPK3, MLKL, NLRP3, IL-18; down-regulated ASC, iNOS, GFAP and MMP-9 expression; and decreased myeloperoxidase activity in cerebral cortex. NAC could protect against HFD-induced neurodegeneration via improving glycemic status and peripheral insulin resistance, disrupting oxidative stress/neuroinflammation/necroptosis/inflammasome activation axis in cerebral cortex. NAC may represent a promising strategy for conserving brain health against metabolic diseases-induced neurodegeneration.