NGF IMPROVES NEURITE FASCICULATION OF EMBRYONIC RAT CEREBRAL CORTICAL NEURAL STEM CELLS ON EVAL SUBSTRATES UNDER SERUM FREE CONDITIONS

Abstract

The behaviors of multipotential neural stem cells are regulated by several factors, including culture substrates, soluble factors, and cell-cell interactions. The purpose of this study was to explore the effects of cell-cell and cell-substrate interactions on developmental potential of neural stem cells from embryonic rat cerebral cortex at neurosphere level in the presence of nerve growth factors (NGF). The results suggested that, in combination with NGF, EVAL substrates could induce neurite fasciculation of differentiated forming-neurosphere cells under serum free conditions. Quantitative analysis of process growth reveals that, under serum free conditions, when NGF was present the process breadth was significantly larger than that of neurospheres cultured without NGF. In contrast, when serum were added in the medium, regardless of the addition of NGF or not, the neurospheres were induced into typically an extensive cellular substratum of protoplasmic cells upon which process-bearing cells spread. It indicated that, when serum was present, the differentiated GFAP-positive astrocytes layer could serve as a supported architectural for growth and survival of process-bearing cells. At this time, neurites were failed to fasciculate. Here, we proposed that the mediation of cell-biomaterial interaction by cell-cell interaction should be taken into account for regulation of neurites fasciculation. Moreover, the pattern of neural stem cell growth on EVAL subtrates with or without NGF in the absence or presence of serum in this studies suggested that neurons are more adherent to glail cells than to other neurons but are more adherent to other neurons than to EVAL substrates.