Objective： To identify the underlying mechanisms of the protective effects of Dingxin Recipe （定心方, DXR）, a Chinese compound prescription that has been used clinically in China for more than 20 years, on ischemia/reperfusion （I/R）-induced arrhythmias in rat model. Methods： A total of 30 rats were randomly divided into three groups： sham group, I/R group, and DXR-pretreated I/R （DXR-I/R） group. Rats in the DXR- I/R group were intragastrically administrated with DXR （12.5 g/kg per day） for consecutive 7 days, while rats in the sham and I/R groups were administrated with normal saline. Arrhythmias were introduced by I/R and electrocardiograms （ECG） were recorded. Two-dimensional （2-D） polyacrylamide gel electrophoresis and matrix- assisted laser desorption ionization time-of-flight mass spectrometry （MALDI-TOF MS） were used to identify differentially expressed proteins. Immunohistochemistry, real-time quantitative polymerase chain reaction （RQ- PCR）, Western blot, and enzyme-linked immunosorbent assay （ELISA） were performed to analyze proteins obtained in the above experiments. Results： DXR significantly reduced the incidence and mean duration of ventricular tachycardia and ventricular fibrillation and dramatically decreased the mortality, as well as arrhythmia score, compared with those of the I/R group. Among successfully identified proteins, prohibitin （PHB） and heart fatty acid binding protein （hFABP） were up-regulated in DXR-pretreated I/R rats compared with those of the I/R rats. In addition, compared with the I/R group, the level of glutathione （GSH） was elevated accompanied by reduced expressions of interleukin-6 （IL-6） and neutrophil infiltration in I/R rats with DXR pretreatment. Conclusions： DXR could alleviate I/R-induced arrhythmias, which might be related to increased expression of PHB. The enhanced expression of PHB prevented against the depletion of GSH and consequently inhibited apoptosis of cardiomyocytes. Furthermore, up-regulation
Objective:To investigate the protective action of tanshinone IIA (TSN) on myocardial apoptosis induced by hydrogen peroxide (H2O2) and its effect on prohibitin (PHB) expression to probe the role of PHB in the oxidation stress of myocardial cells. Methods: Primary cultured neonate rat myocardial cells were cultured with TSN (1×10-4 mol/L) for 24 hours, and then the medium was supplemented with 200 μmol/L hydrogen peroxide for 2 h to initiate myocardial cell oxidative stress injury. PHB in myocardial cells was knocked down by small interfering RNA (siRNA), and the expression level of PHB was determined by western blot analysis. Flow cytometry was used to detect the apoptosis rate, intracellular calcium ion concentration ([Ca2+]i) and mitochondrial membrane potential (MMP). Results: The PHB expression, [Ca2+]i and the apoptotic rate significantly increased, and the MMP significantly decreased in the oxidative stress group compared with the control. The PHB expression, apoptosis rate and [Ca2+]i decreased, and MMP increased significantly in the TSN group compared with the oxidative stress group. Compared with the siRNA negative control group, the PHB expression level in myocardial cells was down-regulated, and the apoptosis rate and [Ca2+]i increased, and MMP decreased significantly in the siRNA group. Conclusion: TSN can reduce PHB expression in oxidative stress-injured myocardial cells hence protecting the myocardial cells.
