CCD生体顕微鏡を用いた心外膜微小リンパ管の拍動変化および流動特性に関する解析

抄録

The aim of present study was to evaluate cardiac lymph dynamics during a cardiac cycle by our CCD intravital microscopes. In anesthetized open-chest dogs, India ink or suspension fluid (Levovist) was injected into the myocardium of the left ventricular apex. The epicardial lymphatics were visualized by India ink using a regular speed (30 frames/s) needle-lens CCD intravital microscope. Velocities of Levovist flowing were calculated by frame-to-frame analysis using a high-speed CCD (200 frames/s) microscope based on the moving distance of Levovist suspension per 5 ms. The diameters of epicardial lymphatics showed an increasing trend from end-diastole to end-systole (6 ± 15%) without statistical significance. Either augmented or decreased contractility did not affect the end-systolic diameter increment (8 ± 12% and 3 ± 9%, respectively), compared with control conditions. Cardiac lymph flow velocity was accelerated in early systolic phase (1.01 ±0.26 mm/s). The mid-systolic dip was followed by late systolic and then early diastolic forward flow. A reverse flow was observed in some cases during late diastolic phase. In conclusions, cardiac lymph flow was slow, but exhibited a clear biphasic systolic forward pattern followed by an occasional small end-diastolic reverse flow, reflecting phasic changes in myocardial strain, pressure and stiffness due to myocardial contraction/relaxation during a cardiac cycle.