LENS EPITHELIUM - A PRIMARY TARGET OF UVB IRRADIATION
LENS EPITHELIUM - A PRIMARY TARGET OF UVB IRRADIATION
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DOI：
10.1006/exer.1994.1141
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发表时间：
1994-11-01
影响因子：
3.4
通讯作者：
DZIEDZIC, DC
中科院分区：
文献类型：
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作者：
HIGHTOWER, KR;REDDAN, JR;DZIEDZIC, DC
用紫外线照射培养的兔晶状体和培养的兔晶状体上皮细胞，观察紫外线诱发白内障形成过程中晶状体上皮细胞的形态变化与整个晶状体的生理变化。使用了两个UV光谱范围；一个跨度为290到340 nm，被指定为近UV，另一个是较窄的纯UVB区域：303到313 nm，被称为UVB。用全晶状体前表面的任何一种光谱照射，都会引起浑浊和离子稳态的剂量依赖性丧失，这是由全晶状体中的Na+和Ca~(2+)浓度测量的。用Rb-86摄取测定的阳离子泵活性在紫外线照射后的培养过程中继续稳步下降。经UVB照射的晶状体上皮细胞层的整装制片在照射后2小时内出现形态变化，20小时后细胞死亡。在整个晶状体的后部照射后，在3天的培养过程中，晶状体上皮细胞仍然存活，晶状体保持透明，这可能是因为紫外线光子没有到达上皮细胞。后纤维细胞膜和蛋白质对紫外光的吸收不会引起混浊。为了进一步了解晶状体上皮细胞的损伤情况，我们对培养的兔晶状体上皮细胞进行了照射。在培养的细胞中，UVB处理在7天内延缓了生长。第7天存活的细胞外观异常，钾浓度比对照组低约50%，这一发现可能解释了先前报道的UVB辐射导致蛋白质合成减少的原因。总而言之，这些数据表明紫外线白内障是由上皮细胞损伤引起的，包括膜通透性的改变导致晶状体内离子稳态的丧失。
Cultured rabbit lenses and cultured rabbit lens epithelial cells were irradiated with UV to correlate morphological changes in the epithelium with physiological changes in the whole lens during the development of UV-induced cataract. Two UV spectral ranges were utilized; one spanned 290 to 340 nm and was designated near-UV, the other was a narrower, pure UVB region: 303 to 313 nm, designated UVB. Irradiation with either spectrum of the anterior surface of whole lenses caused opacification and a dose-dependent loss of ion homeostasis as measured by Na+ and Ca2+ concentrations in whole lenses. It was determined that cation pump activity, assessed by Rb-86 uptake, continued to decline steadily during culture after UV irradiation. Whole mount preparations of the epithelial cell layer of UVB-irradiated lenses revealed morphological changes within 2 hr of irradiation and cell death after 20 hr. Following posterior irradiation of whole lenses, the epithelial cells remained viable and lenses remained transparent during 3 days of culture, presumably because UV photons did not reach the epithelium. Absorption of UV photons by posterior fiber cell membranes and proteins did not cause opacification. To learn more about the epithelial damage, cultured rabbit lens epithelial cells were irradiated. UVB treatment retarded growth over a 7-day period in cultured cells. The surviving cells at day 7 were abnormal in appearance and the potassium concentration was approximately 50% less than controls, a finding which may explain the previously reported reduction in protein synthesis by UVB irradiation. Collectively, the data suggest that UV cataract is initiated by damage to the epithelium, including a change in membrane permeability Leading to loss of ion homeostasis in the lens.