Analysis of an inductive interaction between lens and neural retina in rats of different ages.

Lens epithelial cells from neonatal rats cultured with neural retinas or neural retina-conditioned medium (RCM), undergo fibre differentiation. This is characterized by cell elongation, increased alpha-crystallin synthesis and the initiation of beta and gamma-crystallin synthesis. To determine if this tissue interaction continues in later life we developed an ELISA method to analyse patterns of alpha and beta-crystallin accumulation in epithelia from 3-day-, 10-day- and 21-day-old rats. Culture of lens epithelia with RCM resulted in the formation of multilayers of elongated fibres and the accumulation of alpha and beta-crystallins. The patterns of crystallin accumulation were essentially similar whether expressed as microgram crystallin per explant, or crystallin per DNA (ng per ng). alpha- and beta-Crystallins accumulated rapidly in explants after 2 days of culture in RCM, whereas explants grown in control medium showed no change in the crystallin levels from day 0 to day 10. Patterns of alpha- and beta-crystallin accumulation showed that there were no significant differences between the ability of lens epithelia from 3-day-, 10-day or 21-day-old rats to undergo fibre differentiation in response to RCM. Therefore we conclude that the inductive interaction between lens and neural retina is not restricted to embryonic or neonatal stages, but continues on throughout life maintaining normal patterns of fibre differentiation in the lens.