Effect of hibiscus sabdariffa linn methanolic extract on heart hypertrophy index and PGC-1α in overtrained rat

Objective: Studies have shown that prolonged physical exercise increases ventricular wall mass. Physiologically, this increase is followed by an increase of mitochondrial biogenesis. However, increases of ventricular mass in some cardiovascular diseases are not followed by an increase of PPARγ coactivator-1α (PGC-1α), a marker of mitochondrial biogenesis. No data regarding cardiac PGC-1α during an excessive physical exercise program that causes pathological conditions (overtraining) are available. Thus, we aimed to determine the effect of overtraining on cardiac hypertrophy index and PGC-1α level. Furthermore, we aimed to elucidate the cardio protective effect of Hibiscus sabdariffa Linn. (HSL) administration on these cardiac parameters. Methods: Twenty-five male adult Wistar rats aged 8–10 w were randomly divided into five groups: Control (C), control-HSL (C-HSL), aerobic training (A), overtraining (OT), and overtraining-HSL (OT-HSL). Treatments were conducted five times a week, for 11 w. Differences in heart mass were determined by measuring ratios of ventricular weight to body weight (hypertrophy index). PGC-1α levels were measured using an ELISA method. Results: We found that overtraining increased ventricular wall mass; however, it did not increase cardiac PGC-1α levels, whereas mild-aerobic exercise robustly increased cardiac levels of PGC-1α. Furthermore, administration of a methanol extract of HSL did not show any significant effect on cardiac mass or PGC-1α level. Conclusion: Thus, our study showed that ventricular hypertrophy elicited by overtraining conditions was not followed by an increase in cardiac PGC-1α, and administration of H. sabdariffa extract did not ameliorate this condition.