CALCIUM-INDUCED OPACIFICATION AND LOSS OF PROTEIN IN THE ORGAN-CULTURED BOVINE LENS
CALCIUM-INDUCED OPACIFICATION AND LOSS OF PROTEIN IN THE ORGAN-CULTURED BOVINE LENS
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DOI：
10.1016/0014-4835(86)90051-5
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发表时间：
1986-06-01
影响因子：
3.4
通讯作者：
RINK, H
中科院分区：
文献类型：
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作者：
MARCANTONIO, JM;DUNCAN, G;RINK, H
使用牛晶状体的长期器官培养系统来研究渗透应激对晶状体混浊和晶状体蛋白损失的影响。将晶状体在含有L-[U-14C]酪氨酸的对照培养基中预孵育，以便产生标记的晶状体蛋白。研究了这些晶状体蛋白的命运与两种形式的渗透胁迫的关系。在培养基中添加哇巴因或EGTA会引起严重的渗透膨胀和晶状体单价阳离子平衡的紊乱，但只有前一种处理后晶状体钙含量才会增加。渗透压引起的变化仅在钙含量增加的镜片中伴随着透明度和蛋白质的损失。发现混浊和钙增加主要局限于外皮层纤维。随着晶状体钙含量的不断增加，蛋白质的流失也随着时间的推移而增加。通过凝胶过滤和免疫学技术对从培养介质中回收的蛋白质进行表征。第一个检测到的蛋白质是βL-晶状体蛋白，它构成了整个丢失蛋白质的主要部分，尽管在稍后阶段检测到了α-和γ-晶状体蛋白。钙的增加还导致晶状体蛋白聚集的敏感性发生变化，因为在接触哇巴因后，掺入晶状体高分子量 (HM) 部分的 [14C] 酪氨酸增加，但在接触 EGTA 后则没有增加。讨论了这些发现与人类白内障的相关性。
A long-term system of organ culture for bovine lenses was used to investigate the effect of osmotic stress on lens opacification and crystallin loss. Lenses were pre-incubated in control medium containing L-[U-14C]tyrosine so that labelled crystallins were produced. The fate of these crystallins was studied in relation to two forms of osmotic stress. The addition of either ouabain or EGTA to the medium induced severe osmotic swelling and disturbance of the lens monovalent cation balance, but only the former treatment was followed by an increase in lens calcium. The changes due to osmotic stress were accompanied by loss of transparency and protein only in the lenses with increased calcium. Both opacification and increased calcium were found largely to be confined to the outer cortical fibres. Protein loss increased with time as lens calcium continued to increase. The protein recovered from the incubation medium was characterized by gel filtration and immunological techniques. The first protein detected was .beta.L-crystallin, and this formed the major part of the lost protein throughout, although .alpha.- and .gamma.-crystallins were detected at a later stage. Increased calcium also resulted in a change in the susceptibility of the crystallins to aggregation, since there was an increase in [14C]tyrosine incorporated into the lens high-molecular-weight (HM) fraction after exposure to ouabain, but not after exposure to EGTA. The relevance of these findings to human cataract is discussed.