Reactive astrocytes in explant cultures of glial scars derived from lesioned rat optic nerve: an ultrastructural study.

Explant cultures of glial scars generated by surgical removal of the retina in 3-60-day-old rats were used to determine if reactive astrocytes survive in vitro and how closely reactive astrocytes in culture resemble their in vivo counterparts. Characterization of the composition of age matched glial scars in vivo and in vitro showed that reactive astrocytes survived in glial scar explants even after several weeks in culture. Reactive astrocytes in both neonatal and adult glial scars retained ultrastructural features characteristic of reactive astrocytes in vivo. However, fewer reactive astrocytes survived in culture when explants were prepared from adult rat glial scars. The results of this study demonstrate that tissue culture is a viable model for the study of reactive astrocytes. A critical factor in the survival of reactive astrocytes in culture was the complete removal of myelin debris prior to the establishment of the culture. This outcome suggests that it will be important to clarify why myelin debris persists in culture and how it affects the survival of reactive astrocytes.