Figure 6. Effects of embryonic age and retinal conditioned medium on the TER of RPE.

A small, but significant, increase of TER was observed between E7 and E10, but a large increase was observed between E10 and E14. These age-related differences were preserved after stimulation with conditioned medium.

(a) The TER of RPE isolated on E7 (squares), E10 (diamonds) and E14 (circles) was graphed as a function of days in culture. Cultures were maintained in growth medium (closed symbols, blue lines) or stimulated with E14 retinal conditioned medium (open symbols, green lines). Standard error bars were sometimes smaller than the symbol.

(b) Data is summarized for the cultures described in Figure 5. The measurements were acquired just before the permeability measurements. Conditioned medium from E14 retinas stimulated the TER of all ages about 2 fold. As illustrated by the two experiments in panels A and B, there was some variability in the strength of different preparations of conditioned medium. Confidence levels: # p < 0.05, * p < 0.001.