Hightower K, McCready J
Oakland University, Rochester, MI 48063.
Photochem Photobiol. 1993 Dec;58(6):827-30. doi: 10.1111/j.1751-1097.1993.tb04978.x.
Effects on lens physiology of UVB and UVA used separately and sequentially were investigated using 4 week old rabbit lenses in organ culture. Narrowband UVB at 0.3 J/cm2 = joules/lens (1 h exposure) has little effect on sodium and calcium concentrations in the lens interior or transparency of lenses subsequently cultured for 20 h after a 1 h exposure. With an incident energy of 3 J/cm2 of broadband UVB (295-330 nm), lenses become opaque and slightly swollen with significant ion imbalances during culture over a 1 day period. In contrast, lenses exposed to approximately 6-24 J/cm2 of UVA (330-400 nm) remain transparent after 1 day of culture. Extended culture up to 4 days reveals no signs of opacification. Ion homeostasis and normal lens hydration are also maintained in UVA-irradiated lenses. The presence of 95% oxygen during UVA irradiation is also without effect. Broadband UVA irradiation is damaging, however, if lenses are first exposed to subthreshold doses of narrowband UVB (307 +/- 5 nm) irradiation, viz. 0.3 J/cm2. Thus, sequential UVB/UVA irradiation at subthreshold doses causes impaired active cation transport and accumulation of sodium and calcium accompanying lens opacification.
利用4周龄兔晶状体进行器官培养，研究了单独及先后使用UVB和UVA对晶状体生理的影响。0.3 J/cm²（每晶状体焦耳数）的窄带UVB（1小时照射）对晶状体内部的钠和钙浓度以及在1小时照射后随后培养20小时的晶状体透明度几乎没有影响。对于宽带UVB（295 - 330 nm），入射能量为3 J/cm²时，晶状体在1天的培养过程中会变得不透明且略有肿胀，同时伴有明显的离子失衡。相比之下，暴露于约6 - 24 J/cm²的UVA（330 - 400 nm）的晶状体在培养1天后仍保持透明。延长培养至4天未发现浑浊迹象。UVA照射的晶状体也能维持离子稳态和正常的晶状体水合作用。UVA照射期间存在95%的氧气也没有影响。然而，如果晶状体首先暴露于亚阈值剂量的窄带UVB（307 ± 5 nm）照射，即0.3 J/cm²，宽带UVA照射则具有损害作用。因此，亚阈值剂量的UVB/UVA先后照射会导致活性阳离子转运受损以及伴随晶状体浑浊的钠和钙积累。
