Visualization of nanocontractions in cardiomyocytes by simultaneous detection of second- and third- harmonic generation and multiphoton excitation fluorescence microscopy

摘要

Dynamic imaging of cardiomyocytes was performed with a simultaneous detection second harmonic generation (SHG),third harmonic generation (THG) and multiphoton excitation fluorescence (MPF) microscope. The fast scanning systemof ~12 frames/second synchronized with multichannel detection provided the possibility of imaging three dimensionalstatic and two dimensional dynamic structures of cardiomyocytes. The SHG images highlighted the myofibrils of thecardiomyocytes while THG images revealed the locations of mitochondria. Dynamic data showed that during imaging,chaotic nanocontractions took place inside the cardiomyocytes. The time series of THG images reveled large intensityfluctuations ì flickeringî in the regions of mitochondria. The flickering in THG correlated with the flickering in MPF.Addition of the uncoupler FCCP inhibited flickering in THG and MPF, and also inhibited nanocontractions. Thesimultaneous imaging with SHG, THG and MPF proved to be a very powerful microscopy tool for investigation ofinteractions of different organelles inside a cell.