# Temporal Exercise Conditioning Confers Dual-Phase Cardioprotection Against Isoproterenol-Induced Injury in a Rat Model

## TL;DR

Moderate exercise before and after heart damage in rats reduces injury and improves heart function by lowering oxidative stress.

## Contribution

The study demonstrates that timed moderate exercise provides dual-phase cardioprotection against isoproterenol-induced injury.

## Key findings

- Exercise before and after ISO reduced infarct size and improved left ventricular function.
- HO-1 levels increased and MPO activity decreased with exercise, indicating reduced oxidative stress.
- Echocardiography showed improved stroke volume and ejection fraction in exercised groups.

## Abstract

Exercise training has demonstrated potential benefits in addressing the adverse effects of cardiovascular diseases, particularly myocardial infarction (MI). This study analyzed the cardioprotective effects of moderate exercise before and after MI in rats subjected to isoproterenol (ISO)-induced heart damage. Wistar rats were assigned to five groups: controls (CTRL), isoproterenol-treated (ISO), swimming before ISO (PRE + ISO), swimming after ISO (ISO + POST), and swimming both before and after ISO (PRE + ISO + POST). Cardiac function was assessed through echocardiography, while oxidative stress markers, Heme Oxygenase-1 (HO-1) and Myeloperoxidase (MPO), were quantified using biochemical assays and enzyme-linked immunosorbent assay (ELISA). Statistical analyses were conducted by one-way analysis of variance (ANOVA), accompanied by Tukey’s post hoc test. Exercise performed post-MI and both pre- and post-MI significantly reduced ISO-induced infarct size and improved left ventricular function (stroke volume (SV), ejection fraction (EF), and Tei index). HO-1 protein concentration and HO enzyme activity were restored, while swim training reduced the activity of MPO compared to the ISO group. Moderate exercise training, when appropriately timed, provides cardioprotection against ISO-induced myocardial damage by reducing oxidative stress and cardiac dysfunction.