Exposure to fine particulate matter partially counteract adaptations on glucose metabolism, oxidative stress, and inflammation of endurance exercise in rats

Abstract

Background: Long-term exposure to air pollution triggers metabolic alterations along with oxidative stress and inflammation, while exercise interventions are widely used to improve those parameters. Objective: Our study aimed to determine the effects of subchronic exposure to particulate matter 2.5 (PM_2.5) and endurance exercise training on glucose metabolism, oxidative stress, and inflammation of the heart and gastrocnemius muscle of rats. Material and methods: Thirty-two male Wistar rats were assigned to 4 experimental groups: Untrained; Endurance training (ET); Untrained + PM_2.5; Endurance training + PM_2.5. Rats exposed to air pollution received 50 µg of PM_2.5 via intranasal instillation daily for 12 weeks. Exercised groups underwent endurance training, consisting in running on an electronic treadmill (70% of maximal capacity, 5 days/week, 5 times/week) for 12 weeks. Glucose metabolism markers, redox state, and inflammatory variables were evaluated in the heart and gastrocnemius muscle. Results: ET and ET + PM_2.5 group had lower body mass gain and higher exercise capacity, and higher glycogen concentration in the heart and gastrocnemius muscle. In the heart, ET and ET + PM_2.5 groups had higher levels of GSH, and lower TBARS and TNF-α concentrations. In the gastrocnemius muscle, the ET group showed higher leptin and lower TBARS and IL-1β concentrations, ET and ET + PM_2.5 showed higher superoxide dismutase activity and ROS content. Conclusion: PM_2.5 exposure partially blunts metabolic and inflammatory adaptations in heart and gastrocnemius muscle tissues induced by exercise training.

Keywords:

• Air pollution
• physical training
• cytokines
• redox state
• glucose metabolism
• muscle

Acknowledgments

Bruna Marmett, is supported by doctoral fellowship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Gilson Pires Dorneles is supported by postdoctoral fellowship from (CAPES) and Alessandra Peres and Pedro Roosevelt Torres Romão are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the PQ productivity scholarship.

Ethics approval and consent to participate

This study was approved by UFCSPA's Ethics Commission on Animal Use (protocol number: 159/15).

Author contribution

BM and GPD drafted the first version of the manuscript, designed the scope of the study, and developed the methodology of this study. All authors contributed to the writing of this paper. All authors approved the submission of this version for publication.

Disclosure statement

The authors report there are no competing interests to declare.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.