Tissue printing of astroglial interlaminar processes from human and non-human primate cerebral cortex

Astroglial interlaminar processes are unique features of the cerebral cortex of adult primates, including man. The functional role of these processes in the primate cerebral cortex is largely unknown. The development and standardization of procedures that could maximize the utilization of primate brain samples is required for the experimental analysis of the individual and collective dynamic properties of interlaminar glial processes. With this aim and in order to assess the relative stability of these glial processes in ex vivo conditions, "tissue printing" procedures were applied. "Tissue printing" allows for the acute transfer of cellular elements from fresh tissue onto an artificial substrate. Human, monkey (Cebus apella), and rat brain samples were subjected to "tissue printing" procedures followed by cell culture and immunohistochemistry. For the purpose of comparing the efficiency of this procedure on the transfer of other long glial processes, "tissue prints" of radial glial processes from neonatal rats and of Bergmann glia from cerebellar samples of adult rats were included. Nitrocellulose (with and without added fibronectin or laminin) produced the best attachment results. Interlaminar processes were not modified following 24-h incubation in a cell culture medium, with the addition of agents known to modify astroglial morphotypes in vitro (cyclic adenosine monophosphate, 40 mM K(+), or fetal calf serum). It is concluded that glia with interlaminar processes can be detached from fresh tissue using "tissue printing" procedures, can be maintained for at least 24 h in standard culture conditions, and showed a stable morphological phenotype.