Structural complexity of primary cultures of astrocytes as revealed by transverse sections

The tissue architecture of low-, medium-, and high-density primary mouse astroglial cultures was examined in horizontal and transverse planes using the electron microscope. It was found that the low-density (colony) cultures consisted of a true monolayer, whereas the medium- and high-density (confluent) cultures consisted of anywhere from two to seven overlapping sheets enclosing a substantial intercellular space. The presence of these multiple overlapping sheets in confluent astrocyte cultures should therefore be taken into consideration when interpreting data of cell-membrane-related phenomena such as ion fluxes.