REACTIVE ASTROGLIA SUPPORT PRIMARY DENDRITIC BUT NOT AXONAL OUTGROWTHFROM MOUSE CORTICAL-NEURONS IN-VITRO

Reactive astrocytes are thought to be impediments to axon regrowth fol lowing injury to the mammalian central nervous system. Axon and dendri te growth, however, appear to be differently controlled by normal astr ocytes in vitro. To determine whether reactive astrocytes differ in th eir ability to support axons or dendrites, embryonic (E18) mouse corti cal neurons were cocultured with P4 and P12 rat astroglial cells deriv ed from normal or lesioned cortex. After 5 days in vitro, axon and den drite outgrowth from isolated neurons was quantified with double-label ing immunohistochemical techniques. Reactive astrocytes were able to m aintain primary dendrite growth, principally primary dendrite number. Axon elongation, however, was significantly reduced on both neonatal a nd more mature reactive astrocytes, These results indicate that reacti ve astrocytes may exhibit separate mechanisms to control dendrite and axon growth. (C) 1996 Academic Press, Inc.