Direct intracellular injections for studying human myometrial gap junctions prior to labor

Direct intracellular microinjection of a fluorescent dye (Lucifer Yellow) was performed on ex-situ muscle strips from term pregnant women not in labor. The aim was to characterize the intracellular distribution of LY to obtain criteria for an intracellular injection in whole mounts and ultimately to study the gap junctional communication between myometrial cells in those tissues. Fifteen injections performed on biopsies from ten cases showed a well-bordered fusiform shape and were considered to be intracellular. The intercellular spread of the dye into an adjacent cell was observed in three injections (three cases). The average cell dimension was 284 +/- 95 microns for length and 5 +/- 1.5 microns for width (n = 17). The intracellular injection was confirmed by light microscopy of cross sections. It is concluded that limited coupling exists between myometrial cells of women prior to labor.