Effect of fluorodeoxyuridine on neurons and non-neuronal cells in cerebral explants.

Fetal rat brain neurons are reported to show enhanced neurite development when treated with the mitotic inhibitors fluorodeoxyuridine (FUdR) or cytosine arabinoside (AraC). For AraC-treated rat cerebral explants, increased neurite growth occurs along with a change in the composition of the non-neuronal cell population and diminished non-neuronal cell proliferation. FUdR-treated rat cerebral explants were therefore cultured in an attempt to determine whether FUdR encourages neurite outgrowth by changing the composition and number of non-neuronal cells. Quantitative morphological analyses revealed a significant decrease in the incidence of non-neuronal cells, and an increase in neurite outgrowth for the FUdR-treated explants. These explants also exhibited an increased proportion of protoplasmic astrocytic-epithelial cells and a decreased proportion of fibroblastic-reactive microglial cells. Thus, FUdR may encourage neurite outgrowth through a curtailment of non-neuronal cell proliferation (primarily by fibroblastic-reactive microglial cells) and through the creation of a non-neuronal cell environment consisting almost entirely of protoplasmic astrocytes.