Relationship between reestablishment of sarcolemma-glycocalyx ultrastructures and restoration of transmembrane potentials in cultured rat heart cells

Abstract

Simultaneous studies on sarcolemma-glycocalyx ultrastructures and electrophysiological properties of the trypsin-released rat heart cells were carried out in order to define the relationship between sarcolemmal membrane repair and transmembrane potential recovery in the long-term cultured heart cells. Based on electron microscopic observations of the trypsinized heart cells maintained in the long-term culture, serial alterations of sarcolemma-glycocalyx complex could be divided into three successive stages. A defective stage of the sarcolemma-glycocalyx complex was present in the cultured cells between day 3 and day 6 of incubation. A repaired stage of the sarcolemma-glycocalyx complex was observed in the cells from day 7 to day 9 of incubation. A well-organized stage of the sarcolemma-glycocalyx complex was seen in the cells after ten days of incubation. Sequential measurements of electrophysiological parameters of the cultured heart cells showed a diphasic evolution of maximum diastolic potential and action potential amplitude, with an initial decrease from day 3 to day 9 of incubation and a later return to normal range after ten days of incubation. There seemed a good correlation between electrophysiological properties and sarcolemma-glycocalyx ultrastructures. Thus, we conclude that restoration of the electrophysiological properties of the cultured cells is closely related to the reorganization of the defective sarcolemmal membrane.