Melatonin improves the antioxidant capacity in cardiac tissue of Wistar rats after exhaustive exercise

Abstract

We investigated the effects of melatonin on the onset and resolution of the oxidative stress in the cardiac muscle in melatonin-treated and nontreated rats subjected to an exhaustive exercise session. Forty male rats were divided into: melatonin-treated (20 mg/kg supplemented for 10 d) and control. On the 10th day, each group was subdivided according to euthanasia moments: control or melatonin-treated not exercised (C0h and M0h); immediately after the exercise (CIA and MIA); and 2 h after exercise (C2h and M2h). The heart of animals was removed and the levels of oxidative stress index (OSI) and the formation of thiobarbituric acid reactive substances (TBARS), protein carbonyl, and the activities of aconitase, catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were evaluated. Total antioxidant status (TAS), total oxidant status (TOS), and the protein expression of CAT, GPx, and SOD was also measured. Our data revealed significant differences on: (i) OSI (p=.029), CAT activity (p=.016), CAT content (p<.001), GPx content (p=.014), reduced glutathione levels (p<.001), and aconitase activity (p<.001) for interaction of melatonin; (ii) GPx activity (p=.005), reduced glutathione (p=.004), protein carbonyl (p=.035), and TBARS levels (p=.028) between groups, and (iii) TBARS levels (p=.016) for significance between moments. Although the exhaustive exercise protocol imposed mild oxidative stress on the cardiac tissue of rats, melatonin induced antioxidant responses that rebalanced the redox status of the cardiac tissue, especially after exhaustive exercise.

Keywords:

• Melatonin
• exhaustive exercise
• oxidative stress
• antioxidant
• heart
• redox homeostasis

Acknowledgments

We are indebted for the technical support of Edenilson da Silva Junior and Clarissa Tavares Dias. Also, we would like to thank the anonymous reviewers for their valuable time and the immensurable contribution they offered to this manuscript.

Ethical approval

This experimental project was approved by the ethics committee of the Federal University of São Paulo, filed under CEUA: 5928110418. The experiments were carried out in accordance with the Brazilian Guideline for the Care and Use of Animals for Scientific and Didactic Purposes (DBCA) of the National Council for the Control of Animal Experimentation (CONCEA).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge CAPES, CNPq, and FAPESP for financial support. This work was supported by grants from the Brazilian foundation: Coordination for the Improvement of Higher Education Personnel – Social Demand (CAPES-DS, register number 33009015070P2).