STRUCTURAL RELATIONSHIP BETWEEN MICROLYMPHATIC AND MICROVASCULAR BLOOD VESSELS IN THE RABBIT VENTRICULAR MYOCARDIUM

Abstract

We investigated the distribution andrelationship between draining lymphaticvessels, lymphatic capillaries, and microvascularblood vessels in rabbit ventriculartissue. The left and right ventricular tissuefrom 15 healthy adult rabbits was obtained,processed, and sectioned for analysis. 5’-nucleotidase-alkaline phosphatase (5’-Nase-Alpase) double staining was first used toidentify lymphatic and blood vessels. Dualfluorescent immunohistochemical techniquewas then utilized with lymphatic endothelialcell marker podoplanin and blood vascularmarker PAL-E. In addition, five ventricularsamples were examined for ultrastructureusing transmission electron microscopy (TEM).Draining lymphatic vessels and both lymphaticand blood capillaries were observed in theventricular tissue. The lumens of draininglymphatic vessels were larger and irregularwhile the lymphatic capillaries were small indiameter and abundant. All lymphatic vesselswere located among blood capillaries in themyocardium and aligned with the longitudinalaxis of myocardial cells. The immunofluorescencedouble staining demonstrated thatdraining lymphatic vessels, lymphaticcapillaries, and microvascular blood vesselswere adjacent to each other and the cardiacmyocyte with a ratio of lymphatic to microvascularblood vessels of approximately 1:1.This study suggests that lymphatic and bloodcapillaries exist in abundance and in nearlyidentical numbers in the ventricular myocardiumand that they interweave with each otherto comprise a complicated vessel network.