Age-related changes in fibre differentiation of rat lens epithelial cells in vitro.

Epithelial cells in explants from rat lenses differentiate into fibre cells when cultured with retina conditioned medium (RCM). This differentiation is characterised by cell elongation, the accumulation of alpha-crystallin and the onset of synthesis of the fibre specific beta- and gamma-crystallins. To determine the effect of donor age on the synthesis of beta- and gamma-crystallins in response to culture with RCM, we explanted lens epithelia from 3-, 10- and 21-day-old rats. Explants were trimmed to obtain a population of central epithelial cells and at the end of the culture period crystallin content was measured by ELISA methods and expressed per unit DNA. Explants from 3- and 10-day-old rats showed significant increases in the levels of beta-crystallin/DNA within four days after the addition of RCM. The synthesis of beta-crystallin in explants from 21-day-old rats was delayed until after day 4 of culture, but rose quickly to reach the same levels at 10 days as the explants from younger lenses. The ability of lens epithelia to synthesise gamma-crystallin in response to RCM showed a dramatic decline as the age of the donor rat increased. After 10 days of culture, explants from 10-day-old rats contained only 12% of the amount of gamma-crystallin accumulated by explants from 3-day-old rats. Explants from 21-day-old rats accumulated no significant gamma-crystallin until day 10 of culture, and at this time the amount was significantly less than that accumulated by explants from younger rats.(ABSTRACT TRUNCATED AT 250 WORDS)