International Tomography Center SB RAS, Institutskaya 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia.
Novosibirsk State Regional Clinical Hospital, Nemirovicha-Danchenko 130, Novosibirsk 630087, Russia.
J Photochem Photobiol B. 2017 Aug;173:318-324. doi: 10.1016/j.jphotobiol.2017.06.005. Epub 2017 Jun 3.
The absorption and fluorescence properties of the metabolomic (MET), water-soluble and urea-soluble protein fractions from the middle-age, aged, and cataractous human lenses have been measured. At 280nm and 300nm the major lens absorbers are crystallins, which absorb more than 90% of light in the UV-B region (280-315nm). In middle-aged lenses, the absorption at 360nm is mostly provided by UV filters contained in the MET fraction. With aging, and especially with the cataract development, the absorption of MET fraction in UV-A region (315-400nm) decreases due to the drop of the UV filter concentration, while the absorption of protein fractions increases due to the accumulation of post-translational modifications. Consequently, the contribution of the MET fraction into the total lens absorption at 360nm decays from 63% in middle-aged lenses to 25% in aged lenses to 3% in cataractous lenses. The fluorescence yield of the MET fraction from cataractous lenses also significantly increases. Therefore, the protection of the lens tissue against UV radiation in aged and cataractous lenses weakens: the absorption of UV-A light is mostly provided by modified crystallins and non-UV-filter metabolites, which are photochemically more active than the UV filters. The obtained data indicate that the aged and cataractous human lenses are more vulnerable to UV-A light than the middle-aged lenses.
已经测量了从中年、老年和白内障人晶状体中代谢组学（MET）、水溶性和尿素溶性蛋白质部分的吸收和荧光特性。在 280nm 和 300nm 处，晶状体的主要吸收体是晶体蛋白，它们在 UV-B 区域（280-315nm）吸收超过 90%的光。在中年晶状体中，360nm 处的吸收主要由 MET 部分中包含的 UV 滤光片提供。随着年龄的增长，特别是白内障的发展，由于 UV 滤光片浓度的下降，MET 部分在 UV-A 区域（315-400nm）的吸收减少，而由于翻译后修饰的积累，蛋白质部分的吸收增加。因此，MET 部分在 360nm 处对总晶状体吸收的贡献从中年晶状体的 63%下降到老年晶状体的 25%，再到白内障晶状体的 3%。白内障晶状体中 MET 部分的荧光产率也显著增加。因此，在老年和白内障晶状体中，对晶状体组织的 UV 辐射的保护作用减弱：UV-A 光的吸收主要由修饰的晶体蛋白和非 UV 滤光剂代谢物提供，它们比 UV 滤光剂具有更高的光化学活性。所得数据表明，与中年晶状体相比，老年和白内障人晶状体对 UV-A 光更敏感。
