Laboratory of Eye Histochemistry and Pharmacology, Institute of Experimental Medicine, Center of Excellence, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Photochem Photobiol. 2013 Mar-Apr;89(2):474-82. doi: 10.1111/php.12010. Epub 2012 Nov 28.
Solar UVB radiation evokes photokeratitis, accompanied by increased corneal hydration and changes in corneal transparency, resulting in increased light absorption. Corneal optical properties are disturbed and visual acuity decreased. The aim of this study was to investigate the reversibility of these UVB-induced changes. Rabbit corneas were irradiated with UVB doses of 0.5 J cm(-2) or 1.01 J cm(-2) during 4 days. Some rabbits were sacrificed after the last irradiation and some 2 months later. Corneas were investigated spectrophotometrically for light absorption, and corneal hydration was evaluated by central corneal thickness with an ultrasonic pachymeter. Corneal impression cytologies were examined immunohistochemically for proinflammatory cytokines and malondialdehyde. The increased corneal light absorption, hydration and the staining of immunohistochemical markers found in corneas after irradiation returned to normal values during 2 months in corneas irradiated with the lower UVB dose. In contrast, in corneas irradiated with the higher UVB dose, a moderate but statistically significant increase in corneal light absorption, hydration and positive immunohistochemical stainings remained as residual changes. This was in contrast to normal corneas, where the staining of proinflammatory cytokines as well as malondialdehyde was negative. In conclusion, the reversibility of UVB-induced disturbances was dependent on UVB dose.
太阳紫外线 B（UVB）辐射会引发光性角膜炎，伴随角膜水合作用增加和透明度变化，导致光吸收增加。角膜光学性质受到干扰，视力下降。本研究旨在探讨这些 UVB 诱导变化的可逆性。将兔角膜用 0.5 J/cm²或 1.01 J/cm²的 UVB 剂量照射 4 天。部分兔在最后一次照射后立即处死，部分在 2 个月后处死。用分光光度法检测角膜光吸收，用超声角膜测厚仪测量中央角膜厚度评估角膜水合作用。用免疫组织化学方法检测角膜印迹细胞学中的促炎细胞因子和丙二醛。结果显示，在低剂量 UVB 照射的兔角膜中，照射后增加的角膜光吸收、水合作用和免疫组织化学标记的染色在 2 个月内恢复正常水平。相比之下，在高剂量 UVB 照射的兔角膜中，角膜光吸收、水合作用和阳性免疫组织化学染色仍有中度但统计学上显著的增加，作为残留变化。这与正常角膜形成对比，正常角膜中促炎细胞因子和丙二醛的染色均为阴性。总之，UVB 诱导的干扰的可逆性取决于 UVB 剂量。
