Abstract
The lymphatic system plays a major role in material
and fluid transport in tissues and organs to maintain,
like blood-microcirculation, homeostasis. The
rhythmical contraction of lymph vessels has been
observed frequently in mammalian species; however,
the mechanisms of lymphatic contraction and
lymph transport are not well known. In order to
analyze the rhythmical contraction of lymph vessels
in rat mesentery in vivo, microscopic image processing
technique and effective algorithm for image
analysis were developed in this study. They served
to automatically extract indistinct edge lines of
lymph vessel walls and to measure the vessel diameter
from video images. Continuous measurement
of diameter changes at equi-distant positions along
the lymph vessel was carried out frame by frame.
The results of diameter measurement showed high
correlation with those of direct visual measurement
on the video display. Graphic description of the
lymphatic diameter changes related to time and
position was obtained for further analysis with a
contractile mode of lymph vessel. Lymph volume
change was also calculated using a cylindrical model
of lymph vessel. Periodic contraction of collecting
lymphatics mostly occurred every 4 to 8 sec in rat
mesentery, and was independent of heartbeat, respiration
or skeletal muscle contraction. The results
indicated that the rhythmical contraction of lymph
vessel must be regulated by an active control system.
