Krohne T U, Hunt S, Holz F G
Department of Ophthalmology, University of Bonn, Ernst-Abbe-Str. 2, D-53127 Bonn, Germany.
Br J Ophthalmol. 2009 Jan;93(1):91-5. doi: 10.1136/bjo.2008.145102. Epub 2008 Oct 24.
Translocation of an autologous retinal pigment epithelium (RPE) sheet under the macula is currently under investigation as a treatment for exudative AMD. Excimer laser-assisted RPE sheet translocation (EST) employs intraocular excimer ablation of excess graft choroidal tissue as a measure to enhance RPE sheet functionality. This study assessed potential adverse effects of excimer irradiation on RPE cells in vitro.
Human RPE cells (ARPE-19) received 308 nm XeCl excimer laser treatment or 311-312 nm UV-B irradiation. Cell death was visualised with Trypan Blue and quantified by LDH release assay. Apoptosis was detected by DNA fragmentation assay.
Laser treatment of 0.175-0.25 J/cm(2) resulted in delayed cell death within 48 h. Time course and dose response paralleled the effect of UV-B irradiation. Cytotoxicity was mediated by apoptosis. Human choroid/Bruch membrane tissue sheets covering the cells during laser irradiation reduced cytotoxicity by 87-95%.
Cultured human RPE cells are susceptible to apoptotic cell death induced by 308 nm excimer laser irradiation. Absorption by choroid/Bruch membrane tissue can largely prevent the cytotoxic effect. In clinical application, the residual adverse effect of laser ablation on graft RPE cell viability needs to be outweighed by potential advantageous effects on graft survival and functionality to allow for a sensible application of excimer ablation in RPE translocation surgery.
自体视网膜色素上皮（RPE）片移植至黄斑下目前正作为渗出性年龄相关性黄斑变性（AMD）的一种治疗方法进行研究。准分子激光辅助RPE片移植（EST）采用眼内准分子激光消融多余的移植脉络膜组织，以增强RPE片的功能。本研究评估了准分子激光照射对体外培养的RPE细胞的潜在不良反应。
人RPE细胞（ARPE-19）接受308nm XeCl准分子激光治疗或311 - 312nm UV-B照射。用台盼蓝观察细胞死亡情况，并通过乳酸脱氢酶（LDH）释放试验进行定量。通过DNA片段化试验检测细胞凋亡。
0.175 - 0.25J/cm²的激光治疗导致48小时内细胞死亡延迟。时间进程和剂量反应与UV-B照射的效果相似。细胞毒性是由细胞凋亡介导的。激光照射期间覆盖细胞的人脉络膜/ Bruch膜组织片可使细胞毒性降低87 - 95%。
培养的人RPE细胞易受308nm准分子激光照射诱导的凋亡性细胞死亡影响。脉络膜/ Bruch膜组织的吸收可在很大程度上防止细胞毒性作用。在临床应用中，激光消融对移植RPE细胞活力的残留不良影响需要被对移植存活和功能的潜在有利影响所抵消，以便在RPE移植手术中合理应用准分子激光消融。
