Abstract:

BACKGROUND: Whether transplanted cardiac stem cells (CSCs) can improve ventricular fibrillation threshold (VFT) and whether severe malignant ventricular arrhythmia is induced in the myocardial infarction model are still unclear.
OBJECTIVE: To clarity the electrophysiological characteristics and VFT in rats with myocardial infarction by treatment with allogenic CSCs.
METHODS: Left anterior descending coronary arteries of SD rats were ligated to induce myocardial infarction. Two weeks later, animals were randomized to receive 5×10⁶ CSCs labeled with PKH26 in phosphate buffer solution (PBS) or PBS alone as a placebo by injection into the ischemic zone in the anterior ventricular free wall. Six weeks after the CSCs or PBS injection, electrophysiological characteristics and VFT were measured at the infarct area. Labeled CSCs were observed in 5 µm cryostat sections from each harvested heart.
RESULTS AND CONCLUSION: Compared with the PBS group, the unipolar electrograms activation recovery time dispersions were shorter in the CSCs group, malignant ventricular arrhythmias were significantly less inducible in the CSCs group, the VFTs were greatly improved in the CSCs group. Labeled CSCs were identified in the infarct marginal zone and expressed Connexin-43 and α-sarcomeric actin. CSCs can modulate the electrophysiological abnormality and improve the VFT in rats with myocardial infarction treated with allogenic CSCs and CSCs express muscle and connexin markers in vivo.