OBJECTIVETo explore the effect of Qiangxin Fumai Granule (QFG, a Chinese herbal preparation for treatment of sick sinus syndrome) contained serum (QFG-S) on sinoatrial node cells during Ca2+ overloading induced by simulated ischemia/reperfusion.

METHODSModel Ca2+ overloading cells were established on sinoatrial node cells from newborn rats, with deprivation of oxygen and glucose to simulate ischemia and with restoration of them to simulate reperfusion. Cells were divided into 5 groups, those in the normal and model control groups were modeled directly and those in the treated groups were pre-cultured with UMEM containing respective medicines in aerobic environment for 30 mm before ischemia/reperfusion simulation. Cell Ca2+ concentration and morphology were observed by invert microscope and fluorescence spectrophotometer.

RESULTSMost cells in the model control group revealed cell edema and deformation, even abscission. By HE staining, many minimal vacuole appeared in cytoplasm, with crumpled nuclear membrane, partially damaged. While cells in the QFG-S treated group, either high-dose or low-dose, were attached grew well, with basically smooth and complete membrane and nuclear membrane, normal in size and shape. The intracellular Ca2+ concentration raised significantly after modeling, but it was much lower in the QFG-S treated group than in the model control group (P < 0.01) and it was not changed obviously in the atropine treated group.

CONCLUSIONQFG-S could diminish the injury of cell induced by simulated ischemia/reperfusion, the acting mechanism for treatment of sick sinus syndrome might be related to its effect in relieving Ca2+ overloading and thus protecting cells from injury.