Objective: To evaluate the usage of fluorescent microscope in analyzing cellular apoptosis.
Methods: VP16 (the inhibitor of Top-II) and Azard Sodium(NaN3, the chemical toxic agent) were used to induce cellular apoptosis and necrosis respectively. The cellular changes were analyzed continually and quantitatively by transmission electromicroscope and fluorescent microscope stained by Hoechst 33258.
Results: Under the observation of fluorescent microscope and electromicroscope, HL60 cells showed pyknosis, chromatin aggregation and karyorrhexis (the features of apoptosis) in the induction of VP16; whereas the cells in the induction of NaN3 presented necrotic changes of karyolysis and chromatin diffusion. This indicated that there were different features in cellular apoptosis and necrosis under fluorescent microscope. In a time course observation of fluorescent microscope, the pyknosis began at 4 h after induction and peaked at 8 h, whereas karyorrheix reached 80% at 24 h, suggesting that the pyknosis preceded the karyorrheix.
Conclusion: The fluorescent microscopic observation is a technique in continual and quantitative analysis of apoptosis, which may be used to distinguish the cellular apoptosis and necrosis.