Objective Previous investigations have shown that N-acetylcysteine （NAC） could regulate diverse cell type＇s apoptosis. The purpose of this study was to evaluate the mechanism of NAC reversed apoptosis of cardiomyocytes induced by hypoxia-reoxygenation （H/R）. Methods Cardiomyocytes were treated with hypoxia 6 h and reoxygenation 72 h in the absence and presence of NAC （100/2mol/ L）. The ROS was assayed by using Image-iTTM LIVE green reactive oxygen species detection kit. The viability of cell was assayed with trypan blue. Early stages ofapoptosis were assessed by flow cytometry using Annexin V, and late stages of apoptosis were assessed using TUNEL system. Bcl2 and bax mRNA levels were determined by real-time quantitative PCR. Bcl2, bax, p38 and pp38 protein levels were determined by western blot. Results We found that H/R could markedly increase ROS generation and induce the apoptosis of cardiomyocytes （P〈0.01）. NAC （10012 mol/L） significantly reduced the generation of ROS and apoptosis （P all 〈0.01）. NAC also significantly reduced the protein ratio of pp38 and p38 and increased the RNA and protein ratio of bcl2 and bax （P all 〈0.01）. Conclusion The results showed that NAC significantly reduced apoptosis through inhibiting the phosphorylation of p38 signal pathway, which has potential value for clinical cardiac diseases （J Geriatr Cardio12009; 6：168-172）.
Feng-Xiang Zhang Ming-Long Chen Bing Yang Ke-Jiang Cao
Background Radiofrequency catheter ablation （RFCA） necessarily produces an area of myocardial necrosis. However, the difference of the extent of myocardial injury between circumferential pulmonary vein isolation （CPVI） and complex fractionated atrial electrograms （CFAE） ablation in patients with atrial fibrillation （AF） has not been investigated before. Methods Twenty-nine consecutive male patients （n=29） with either paroxysmal or persistent AF were selected for CPVI or CFAE ablation. The CPVI or CFAE ablation was performed with a three-dimensional electroanatomical mapping system （CARTO）. Serum cardiac biomarkers, for example, cardiac troponin T （cTnT）, aspartate transaminase （AST）, lactate dehydrogenase （LDH）, creatine kinase （CK）, and creatine kinase myocardial bound （CKMB） were determined by the Elecsys STATE immunoassay. Cardiac structure and function were measured with echocardiography. Results Echocardiography showed that there was no significant difference of atrioventricular structure or function parameters between the CPVI group and the CFAE ablation group. Serum cTnT showed a significant increase in the CFAE ablation group over the CPVI group at 12 and 24 hours after the procedure （P〈0.05, respectively）, and then it was reduced to a normal level after 48 hours. Serum AST showed a significant increase in the CFAE ablation group over the CPVI group at post-procedure, 4 and 12 hours after the procedure （P 〈0.05, respectively）, and then it reached to a normal level after 24 hours. There was no significant difference in LDH, CK, or CKMB levels between the CFAE ablation group and the CPVI group at any time point （P〉0.05）. Conclusions cTnT and AST other than LDH, total CK or CKMB activity significantly increased more in the CFAE ablation group than the CPVI group. However, the difference of the serum levels of cTnT, AST between two groups was temporary.
ZHANG Feng-xiang YANG Bing CHEN Hong-wu JU Wei-zhu CAO Ke-jiang CHEN Ming-long
