Abstract: AIM: To study the effect of simvastatin on cardiac function and mitochondrion of rats with diastolic heart failure (DHF) and its mechanism.METHODS: 50 SD rats were randomly divided into 5 groups: control group, DHF group, simvastatin 1mg group (S1 group), simvastatin 2mg group(S2 group) and simvastatin 4 mg group (S4 group).DHF model was produced by abdominal aortic coarctation in rats of the operating group.The rats in simvastatin groups were given with simvastatin (1, 2, 4 mg°kg^-1 °d^-1) by intragastric administration for 4 weeks, the others were treated with equal isotonic Na chloride.After 4 weeks, the cardiac function and hemorheology were assessed by echocardiography and catheterization.The level of malonaldehyole (MDA), superoxidedismutase (SOD) and glutathioneperoxidase(GSH-Px) were detected by spectrophotometer.Ultra structure changes in myocardium were observed under electron microscope.RESULTS: In DHF group, the left ventricular posterior wall (LVPW), interventricular septum (IVS), left ventricular cardiac index (LVM), E A ratio, left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP) and MDA were increased, the left ventricular relaxation time (Tau) was prolonged, the LV-dp dt_max, SOD and GSH-Px were decreased.The myocardium damage including abnormality of myofilament arrangement, mitochondrial swelling and vacuolization were showed.Compared with DHF group, the cardiac function and hemorheology were improved in the treatment groups.The myocardium damage was ameliorated in the simvastatin group too.The protective effect of simvastatin on heart was increased according to the dose of simvastatin.CONCLUSION: Simvastatin improves cardiac diastolic function in rats with DHF by ameliorating the damage of myocardial cell and mitochondrion.

Key words: simvastatin, diastolic heart failure, myocardial cell, mitochondrion