Interaction of Diet and Ozone Exposure on Oxidative Stress Parameters within Specific Brain Regions of Male Brown Norway Rats

Joseph Valdez,Joyce Royland,Judith Schmid,Andrew Johnstone,Prasada Kodavanti,Judy Richards

doi:10.3390/ijms20010011

Abstract

Oxidative stress (OS) contributes to the neurological and cardio/pulmonary effects caused by adverse metabolic states and air pollutants such as ozone (O3). This study explores the interactive effects of O3 and diet (high-fructose (FRUC) or high–fat (FAT)) on OS in different rat brain regions. In acute exposure, there was a decrease in markers of reactive oxygen species (ROS) production in some brain regions by diet and not by O3. Total antioxidant substances (TAS) were increased in the cerebellum (CER) and frontal cortex (FC) and decreased in the striatum (STR) by both diets irrespective of O3 exposure. Protein carbonyls (PC) and total aconitase decreased in some brain regions irrespective of exposure. Following subacute exposure, an increase in markers of ROS was observed in both diet groups. TAS was increased in the FC (FAT only) and there was a clear O3 effect where TAS was increased in the FC and STR. Diet increased PC formation within the CER in the FAT group, while the hippocampus showed a decrease in PC after O3 exposure in controls. In general, these results indicate that diet/O3 did not have a global effect on brain OS parameters, but showed some brain region- and OS parameter-specific effects by diets.

Highlights

Over the past few decades, there has been an increase in both diabetes and obesity throughout the world, with steeper trends seen in more developed countries that have adopted the Western diet rich in refined sugars and saturated fats (SF) [1,2]
Acute Exposure: In order to measure the production of reactive oxygen species (ROS), NQO1 and ubiquinone reductase (UBIQ-RD) activities were assessed
Ubiquinone reductase (UBIQ-RD) is the first complex of the electron transport chain found in the inner membrane of the mitochondria and is crucial for ATP production [25] and plays a role in neurodegenerative diseases [26,27,28,29]

Summary

Introduction

Over the past few decades, there has been an increase in both diabetes and obesity throughout the world, with steeper trends seen in more developed countries that have adopted the Western diet rich in refined sugars and saturated fats (SF) [1,2]. Research into the effects of consuming these diets has revealed a strong correlation with severe metabolic disorders such as type 2 (non-insulin-dependent) diabetes and obesity [3]. A diet rich in fat has been shown to lead to OS within the hepatic tissue of rats [9]. It is well established that the SNS can exacerbate and possibly causes physiological symptoms associated with obesity, metabolic syndrome, and diabetes by causing insulin resistance, increased heart rate and blood pressure, and increased lipolysis in visceral fat [12,13]

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