Citation:

Kodavanti, P., A. Johnstone, J. Valdez, D. Freeborn, P. Phillips, Judy Schmid, AND M. Valdez. MITOCHONDRIAL BIOENERGETICS FOLLOWING OZONE EXPOSURE IN SEDENTARY VERSUS ACTIVE LIFESTYLE OF FEMALE LONG-EVANS RATS. 57th Annual Meeting of Society of Toxicology, San Antonio, Texas, March 11 - 15, 2018.

Impact/Purpose:

These preliminary results will be presented at the annual SOT meeting in San Antonio, TX. This study is a part of a large project to understand the interaction between chemical exposure and sedentary or active lifestyle. These results indicate that brain mitochondrial bioenergetics were altered to some extent in actively trained rats and O3 exposure had effects only on active rats but not those on sedentary ones suggesting an interaction of lifestyle and O3 effects on brain mitochondrial bioenergetics parameters.

Description:

Mitochondria are key regulators of cellular energy homeostasis and may play a key role in the mechanisms of neurodegenerative disorders and chemical induced neurotoxicity. However, mitochondrial bioenergetic parameters have not been systematically evaluated within multiple brain regions in sedentary versus active lifestyle following environmental pollutant exposures. In the present study, we measured complex I, complex II and complex IV enzymes in the frontal cortex (FC), cerebellum (CER), hypothalamus (HYP), and hippocampus (HIP) in female Long-Evans rats (N = 5 per group) that were sedentary or active with continuous access to running wheels starting at postnatal day (PND) 22 until the age of PND 100 and subjected to Ozone (O3) exposure (0, 0.25, 0.5 or 1.0 O3 for 5 h/day for two consecutive days). Immediately following O3 exposure, rats were sacrificed, brain regions were dissected on ice, quick frozen on dry-ice, and stored at -80oC until analysis. Complex 1 enzyme activity (NADH dehydrogenase, EC 1.6.5.3) in CER and FC was not significantly altered by O3 exposure, however, there was an increase of activity in active animals following 0.5 ppm O3 (p<0.05) exposure. A similar effect was observed in HIP, but it was not significant (p=0.0561). Complex II enzyme activity (succinate dehydrogenase, EC 1.3.5.1) was increased in the FC of active animals but was not significant (p=0.05627). The HIP showed a significant reduction in Complex II activity at 0.25 ppm (p=0.0041) in active versus sedentary animals. Complex IV enzyme activity (cytochrome c oxidase, EC 1.9.3.1) was reduced at 1 ppm in the FC in the running wheel group but was not significant (p=0.062). These results indicate that brain mitochondrial bioenergetics were altered to some extent in actively trained rats and O3 exposure had effects only on active rats but not those on sedentary ones suggesting an interaction of lifestyle and O3 effects on brain mitochondrial bioenergetics parameters. (This abstract does not necessarily reflect USEPA policy).

Record Details: