Effects of nutritional state, aging and high chronic intake of sucrose on brain protein synthesis in rats: modulation of it by rutin and other micronutrients

Abstract

Little is still known about brain protein synthesis. In order to increase our knowledge of it, we aimed to modulate brain protein synthesis rates through aging, variations in nutritional state (fed state vs. fasted state), high sucrose diet and micronutrient supplementation. Four groups of 16 month-old male rats were fed for five months with a diet containing either 13% or 62% sucrose (wheat starch was replaced with sucrose), supplemented or not with rutin (5 g kg⁻¹ diet), vitamin E (4×), A (2×), D (5×), selenium (10×) and zinc (+44%) and compared with an adult control group. We measured cerebellum protein synthesis and hippocampus gene expression of antioxidant enzymes, inflammatory cytokines and transcription factors. We showed that cerebellum protein synthesis was unchanged by the nutritional state, decreased during aging (−8%), and restored to the adult level by micronutrient supplementation. Sucrose diet did not change protein synthesis but reduced the protein content. Micronutrient supplementation had no effect in sucrose fed rats. Hippocampus gene expressions were affected by age (an increase of TNF-α), sucrose treatment (an increase of IL-1β and IL-6), and micronutrient supplementation (a decrease of heme oxygenase, catalase, glutathione peroxidase, TNF-α, and Nrf2). We noted that cerebellum protein synthesis and hippocampus TNF-α gene expression were modulated by the same factors: they were affected by aging and micronutrient supplementation and unchanged by feeding and by high sucrose diet.