Mitochondrial superoxide anions induced by exogenous oxidative stress determine tumor cell fate: an individual cell-based study / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

OBJECTIVE@#Reactive oxygen species (ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli.@*METHODS@#Modified microfluidics and imaging techniques were used to determine O2 •- levels and construct an O2 •- reaction network. To elucidate the consequences of increased O2 •- input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca2+ levels, mitochondrial Ca2+ uptake, auto-amplification of intracellular ROS and the intrinsic apoptotic pathway.@*RESULTS AND CONCLUSIONS@#Results from a modified microchip demonstrated that 1 mmol/L H2O2 induced a rapid increase in cellular O2 •- levels (>27 vs. >406 amol in 20 min), leading to increased cellular oxidizing power (evaluated by ROS levels) and decreased reducing power (evaluated by glutathione (GSH) levels). In addition, we examined the dynamics of cytosolic Ca2+ and mitochondrial Ca2+ by confocal laser scanning microscopy and confirmed that Ca2+ stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca2+ bursts. It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate. The stress response involves the transfer of Ca2+ signals between organelles, ROS auto-amplification, mitochondrial dysfunction, and a caspase-dependent apoptotic pathway.

Effects of nitroglycerine of different concentrations on rat cardiac preservation for 8h / 上海第二医科大学学报

Objective To investigate the effects of Thomas solution in combination with nitroglycerine of different concentrations on rat cardiac preservation for 8 h. Methods Thirty Wistar rats were selected,and Langendorff heart perfusion models were established.Rats were randomly divided into Thomas solution group,Thomas solution+4?10-6 mol/L nitroglycerine group and Thomas solution+4?10-5 mol/L nitroglycerine group(n=10).After hypothermic preservation(4 ℃)for 8 h,the cardiac function of each group was determined.Tissues of left ventricular wall were obtained,and changes of myocardial ultrastructure were observed by electron microscopy. Results Compared with Thomas solution group,the cardiac function was significantly improved and the myocardial ultrastructure injury was less severe in Thomas solution+4?10-5 mol/L nitroglycerine group after hypothermic preservation(4 ℃)for 8 h,while there was no significant difference in myocardial ultrastructure injury and cardiac function between Thomas solution group and Thomas solution+4?10-6 mol/L nitroglycerine group. Conclusion Thomas solution in combination with 4?10-5 mol/L nitroglycerine can significantly improve the preservation effects for isolated hearts in rats.