Richardson N A, McAvoy J W
Department of Histology and Embryology, University of Sydney, N.S.W., Australia.
Exp Eye Res. 1990 Feb;50(2):203-11. doi: 10.1016/0014-4835(90)90232-j.
Epithelial cells explanted from neonatal rat lenses undergo changes characteristic of fibre differentiation when cultured with neural retina, neural retina-conditioned medium (RCM), or acidic and basic fibroblast growth factor (FGF). In neonates fibre differentiation is marked by cell elongation, the accumulation of alpha-crystallin, and the appearance of beta- and gamma-crystallins. To analyze the fibre differentiation response of lens epithelial cells in later life, we compared the fibre differentiation responses of lens epithelia from 3-, 10- and 21-day- 14-week-, and 6-month-old rats to basic fibroblast growth factor (bFGF). Explants of the central epithelium were used to maintain consistency between ages. Crystallin composition of explants was analyzed by immunofluorescence and ELISA methods. Only explants from 3-day-old rats demonstrated any ability to synthesize gamma-crystallin in response to bFGF. Central lens epithelia explanted from rats up to 14 weeks old accumulated alpha- and beta-crystallins when exposed to bFGF. The onset of crystallin accumulation, however, was increasingly delayed, and the amount of crystallin accumulated by the end of the culture period declined as the age of the donor rat increased. The diminished ability of lens epithelial explants from older rats to undergo fibre specific changes in response to bFGF is also demonstrated in the reduced degree of morphological changes characteristic of fibre differentiation. Cell elongation and multilayering in response to bFGF was observed in explants from 3-day-old rats but was substantially reduced in explants from 14-week-old rats. Explants from 6-month-old rats failed to demonstrate any evidence of morphological change or crystallin accumulation in response to bFGF.(ABSTRACT TRUNCATED AT 250 WORDS)
从新生大鼠晶状体中分离出的上皮细胞，在与神经视网膜、神经视网膜条件培养基（RCM）或酸性和碱性成纤维细胞生长因子（FGF）一起培养时，会经历纤维分化的特征性变化。在新生儿中，纤维分化的标志是细胞伸长、α-晶状体蛋白的积累以及β-和γ-晶状体蛋白的出现。为了分析晶状体上皮细胞在生命后期的纤维分化反应，我们比较了3日龄、10日龄、21日龄、14周龄和6月龄大鼠的晶状体上皮对碱性成纤维细胞生长因子（bFGF）的纤维分化反应。使用中央上皮的外植体以保持不同年龄之间的一致性。通过免疫荧光和ELISA方法分析外植体的晶状体蛋白组成。只有3日龄大鼠的外植体表现出对bFGF有合成γ-晶状体蛋白的能力。从14周龄以下大鼠分离的中央晶状体上皮在暴露于bFGF时会积累α-和β-晶状体蛋白。然而，晶状体蛋白积累的开始越来越延迟，并且随着供体大鼠年龄的增加，培养期结束时积累的晶状体蛋白量下降。老年大鼠晶状体上皮外植体对bFGF发生纤维特异性变化的能力减弱，这也体现在纤维分化特征性形态变化程度的降低上。在3日龄大鼠的外植体中观察到对bFGF的细胞伸长和多层化，但在14周龄大鼠的外植体中显著减少。6月龄大鼠的外植体在暴露于bFGF时未表现出任何形态变化或晶状体蛋白积累的迹象。（摘要截断于250字）
