Effect of high-fructose and high-fat diets on pulmonary sensitivity, motor activity, and body composition of brown Norway rats exposed to ozone

Abstract

Diet-induced obesity has been suggested to lead to increased susceptibility to air pollutants such as ozone (O3); however, there is little experimental evidence. Thirty day old male and female Brown Norway rats were fed a normal, high-fructose or high-fat diet for 12 weeks and then exposed to O3 (acute - air or 0.8 ppm O3 for 5 h, or subacute - air or 0.8 ppm O3 for 5 h/d 1 d/week for 4 weeks). Body composition was measured non-invasively using NMR. Ventilatory parameters and exploratory behavior were measured after the third week of subacute exposure. Bronchoalveolar lavage fluid (BALF) and blood chemistry data were collected 18 h after acute O3 and 18 h after the fourth week of subacute O3. The diets led to increased body fat in male but not female rats. O3-induced changes in ventilatory function were either unaffected or improved with the fructose and fat diets. O3-induced reduction in exploratory behavior was attenuated with fructose and fat diets in males and partially in females. O3 led to a significant decrease in body fat of males fed control diet but not the fructose or fat diet. O3 led to significant increases in BALF eosinophils, increase in albumin, and reductions in macrophages. Female rats appeared to be more affected than males to O3 regardless of diet. Overall, treatment with high-fructose and high-fat diets attenuated some O3 induced effects on pulmonary function, behavior, and metabolism. Exacerbation of toxicity was observed less frequently.

Beta-2 Adrenergic and Glucocorticoid Receptor Agonists Modulate Ozone-Induced Pulmonary Protein Leakage and Inflammation in Healthy and Adrenalectomized Rats

“…The changes in lavageable macrophages after ozone exposure are likely influenced by the temporality of the assessment (Kumarathasan et al, 2015;Laskin et al, 1998). Increased adhesion of activated alveolar macrophages might reduce the efficiency of recovery during lavage procedure (Bhalla et al, 1996;Gordon et al, 2016). While the decrease in alveolar macrophages after ozone exposure on D þ 1 was prevented by AD, it is noteworthy that CLENþDEX treatment increased alveolar macrophages but only in ozone-exposed rats (SH > AD).…”

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

“…In this study, we attempt to understand the combined effects of O 3 exposure and different diets on oxidative stress (OS) parameters in different brain regions of rats. The diets (FRUC and FAT) chosen are thought to be associated with adverse metabolic states and are also of concern in compounding effects to environmental toxicant exposure [20]. In short, juvenile rats were given either a control, high-fat, or high-fructose diet and exposed to either air (control) or 0.8 ppm O 3 in acute or subacute exposure paradigms.…”

“…In male Brown Norway rats, tidal volume and breathing frequency (high-fat only, subacute) were somewhat improved, while Penh (a metric of ventilatory resistance) and minute ventilation were exacerbated (both high-fat and high-fructose, subacute only). Vertical and horizontal exploratory (subacutely) behaviors where improved in both high-fat and high-fructose diets, while high-fructose diet alone gave some metabolic improvement in cholesterol and triglyceride serum levels [20]. O 3 treatment alone led to significant increases in pulmonary pathology [20] with an increase in bronchoalveolar lavage fluid eosinophil counts (high-fat and high-fructose, subacute).…”

“…There are few, if any, studies related to the possible interaction between diet and O 3 , especially on brain neurochemistry. Studies using the same cohort of rats showed that treatment with high-fructose and high-fat diets attenuated some O 3 -induced effects on pulmonary function, neurobehavior, and metabolism [20]. The purpose of this study is to further understand this interaction by exploring the potential for high-fat or high-fructose effects on OS within specific brain regions of animals exposed to O 3 either acutely or subacutely.…”

Active vs. sedentary lifestyle from weaning to adulthood and susceptibility to ozone in rats

“…Overall, rats were studied in blocks of 20 each day over a 1-wk period with all animals exposed to ozone, tested for ventilatory function and glucose tolerance, and terminated. We chose a maximum ozone concentration of 1.0 ppm with the expectation that this concentration in other rat strains would evoke profound pulmonary inflammatory responses as we have shown in previous studies using concentrations of 0.8 -1.0 ppm (11,12). The lower concentrations were selected to develop a doseresponse.…”