Objective: To explore sarcoplasmic reticulum ryanodine receptor2 (RyR 2) expression and calcium releasing function in chronic heart failure (CHF) rabbits and to study the impact of long term valsartan treatment in relevant animals. Methods: HF model was established by volume overloading with pressure overloading in experimental rabbits. 27 rabbits were divided into 3 groups: Sham group, HF group and HF+valsartan group. n=9 in each group and the animals were treated for 7 weeks. Left ventricular structure, hemodynamic parameters, expression and functional changes of myocardiocyte sarcoplasmic reticulum RyR 2 were observed and compared among different groups. Results: Compared with Sham group, HF group had increased left ventricular mess index (LVMI), left ventricular end diastolic pressure (LVEDP) and decreased left ventricular shortening fraction, LVEF, all P<0.05. Compared with HF group, HF+valsartan group showed decreased LVMI, LVEDP and increased left ventricular shortening fraction, LVEF, all P<0.05. Sarcoplasmic reticulum RyR 2 expression and calcium releasing function were lower in HF group than Sham group, P<0.05; while they were both higher in HF+valsartan group than HF group, P<0.05. Conclusion: Long term application of valsartan could improve the cardiac function which might be related to increased myocardial sarcoplasmic reticulum RyR 2 expression and calcium releasing function in experimental CHF rabbits.

Objective: To explore the changes of protein expression and activity of calcium/calmodulin-dependent protein kinase-II (CaMK-II) in myocardium nucleus and sarcoplasmic reticulum in experimental rabbits with heart failure (HF).
Methods: A total of 16 rabbits were divided into 2 groups: Sham group and HF group, the HF model was established by volume overload plus pressure overload.n=8 in each group and all animals were treated for 7 weeks. Left ventricular structure, hemodynamic parameters and protein expression and activity of CaMK-II in myocardium nucleus and sarcoplasmic reticulum were examined and compared between 2 groups.
Results: Compared with Sham group, HF group presented increased left ventricular mass index (LVMI) (1.32 ± 0.06) g/kg vs (3.61 ± 0.09) g/kg, LVEDP (-1.50 ± 0.50) mmHg vs (23.00 ± 2.37) mmHg, allP<0.05; while decreased left ventricular shorten fraction (37.83 ± 3.58) % vs (17.38 ± 3.13) % and LVEF (71.92 ± 4.56) % vs (38.50 ± 6.07) %, allP<0.05. The protein expression and activity of CaMK-II were both higher in HF group than Sham group, allP<0.05.
Conclusion: Increased protein expression and activity of CaMK-II in myocardium nucleus and sarcoplasmic reticulum might be one of the mechanisms for HF occurrence in experimental rabbits.