Fig. 5.

PR survival in vitro is modulated by FGF-2 and EGF. Relative percentages of surviving PR isolated from 5-d-old rat retinas were calculated by comparing the number of live PRs at a given time with the number after 24 hr in vitro. In the control after 3 d in vitro, 52.1% represents 24,000 live PRs per coverslip. After 24 hr in vitro, PR culture serum-supplemented medium was replaced with CDM with or without FGF-2 (20 ng/ml) or EGF (10 ng/ml), and aliquots of growth factors or the same volume of CDM were added again after 3 and 5 d. FGF-2-treated PR survived significantly better than EGF-treated or nontreated PRs, particularly after 5 d in vitro. EGF-treated PRs degenerated faster than control PRs. Between 5 and 7 d in vitro, PRs degenerated rapidly in both treated and nontreated wells. Error bars are SEM (n= 8). *p < 0.01; **p < 0.001.