Quantitative Analysis of Intracellular Calcium and Mitochondrial Kinetic Fluorescence Changes in GSNO-induced Thymocyte Early Apoptosis

摘要

A fluorescence microscopy imaging technique was applied to observe the single-cell kinetic changes of intracellular Ca2+ concentration ([Ca2+]_i) and mitochondrial membrane potential (ΔΨ_m) during the early stage of S-nitrosoglutathione (GSNO)-induced thymocytes apoptosis. The kinetic features of [Ca2+]_i and ΔΨ_m were quantitatively analyzed and compared by fitting the fluorescence intensity data. The mathematical parameter, inflection point which indicated the time point when [Ca2+]_i or ΔΨ_m changed the most rapidly, was proposed to analyze the fitting curve. The results revealed that the inflection point of [Ca2+]_i always appeared prior to that of ΔΨ_m during apoptosis induced by a certain GSNO concentration. Both the [Ca2+]_i and ΔΨ_m changed in a GSNO concentration-dependent manner. Another parameter, half-max effect point was also employed and displayed the similar results. Such quantitative analyses of real-time observations at the single-cell level are useful for interpreting the sequence of the biological events operating in GSNO-induced thymocyte apoptosis.