Promotion of neurite outgrowth and cell survival in dissociated fetal rat retinal cultures by a fraction derived from a brain extract

Abstract

We have reported previously that a fraction (BE) derived from a pig brain extract stimulated neurite outgrowth and cell survival from fetal rat retinal explants. The BE effects were dose dependent and could not be altered by NGF or its antiserum. In the present study we have observed that under similar culture conditions BE was also capable of stimulating neurite outgrowth and cell survival from fetal rat dissociated retinal cells. More specifically, the neurite-promoting activity of BE was found to be dose dependent over a concentration range of 0–50 μg/ml with a half-maximal response between 5 and 10 mg/ml. The ability of BE to stimulate neurite outgrowth was also age-related. There was a progressive decrease in the BE-mediated response between fetal day 17 and the second neonatal day. Viable process bearing cells could also be maintained in culture for at least two weeks in the presence of BE (25 μg/ml). In contrast, after 1 day in culture control cells began to rapidly degenerate and by days 3–5 no process-bearing cells were observed. The BE was found to exert its action primarily through a soluble factor(s) in the culture medium. However, we also report evidence for a substrate bound component of the BE which may aid in the attachment and/or neurite outgrowth phenomena.