Increase of myocardial performance by Rhodiola-ethanol extract in diabetic rats

Ethnopharmacological relevance: Rhodiola rosea (also known as golden root or roseroot) is a perennial plant of the Crassulaceae family that grows in the Arctic and in the mountainous regions of Europe, Asia, and North America. The rhizome and roots of this plant have been long used as traditional medicine in Eastern Europe and Asia for enhancing physical and mental performance.

Aim of the study: The present study is designed to investigate the cardiac action of Rhodiola-ethanol extract in streptozotocin-induced diabetic rats (STZ-diabetic rats) with heart failure.

Materials and methods: Diabetes was induced in Wistar rats by injection of streptozotocin. We measured the changes of body weight, water intake, and food intake in three groups of age-matched rats; the normal control received vehicle, STZ-diabetic rat received Rhodiola-ethanol extract or vehicle. Cardiac output, heart rate, blood pressure, and hemodynamic dP/dt in addition to plasma insulin and glucose level were also determined. The mRNA and protein levels of PPARδ were measured using real-time PCR and Western blotting, respectively.

Results: Food intake, water intake and blood glucose were raised in STZ-diabetic rats showing lower body weight and plasma insulin, as compared with the control. Also, cardiac output, heart rate, blood pressure and hemodynamic dP/dt were markedly reduced in STZ-diabetic rats indicating the heart failure physiologically. After a 21-day treatment with Rhodiola-ethanol extract, cardiac output was raised in STZ-rats while the diabetic parameters were not modified. The PPARδ expression of both mRNA and protein was markedly elevated in the heart of STZ-rats receiving treatment with Rhodiola-ethanol extract. Also, the increased phosphorylation level of cardiac troponin-I was restored by this treatment with Rhodiola-ethanol extract. Otherwise, increase of cardiac output by Rhodiola-ethanol extract was blocked by antagonist of PPARδ in STZ-diabetic rats.

Conclusions: Our results suggest that ethanol extract of Rhodiola has an ability to increase the cardiac output in STZ-diabetic rats showing heart failure. Also, increase of PPAR-δ is responsible for this action of Rodiola-ethanol extract.