准分子激光切削脉络膜制备视网膜神经上皮和色素上皮联合植片

Comparison of Microablation of Choroidal Tissue by LASIK and PTK Mode for Neuroretina RPE Cograft Sheets

目的应用准分子激光微切削脉络膜获得视网膜神经上皮及色素上皮联合移植片。方法将PN1-6广西巴马猪眼球冰浴下祛除巩膜、前节和玻璃体,环钻制成视网膜神经上皮-色素上皮-脉络膜复合体。将复合体脉络膜面向上平铺于直径7mm圆形明胶片上,置于无菌培养皿中。采用准分子激光鹰视酷眼系统,准分子激光角膜原位磨镶术(laserin situkeratomileusis,LASIK)和光治疗性角膜切削术(phototherapeutic keratectomy,PTK)模式发射,切削区域直径为6·5mm。LASIK模式矫正范围-2·64^-4·44D;PTK模式切削深度45~75μm。将切削后的标本浸泡于4%多聚甲醛中固定2~3d,石蜡包埋、切片、HE染色。结果使用LASIK模式矫正-4·44D相当于PTK模式切削深度67μm,可见被切削的脉络膜边缘到达RPE基底膜;而使用LASIK模式矫正-3·00D或PTK模式切削45μm时,都仅能祛除脉络膜主体。在判断切削终点上,PTK模式较LASIK模式容易。结论准分子激光切削脉络膜可获得较好的视网膜神经上皮和色素上皮联合移植片,避免了用酶消化对视网膜神经上皮的破坏。LASIK和PTK模式都可以到达所需切削的脉络膜深度,但PTK模式更适合这种取材方法。切削深度的变化应当考虑固定方法、组织的含水量及个体间脉络膜厚度的变化等因素。

Objective To obtain neuroretina-RPE cograft sheets using excimer laser for microablation of choroidal tissue. Methods Eyes from normal Guangxi Bama pigs postnatal days 1-6 （ PN 1-6） were removed the sclera, the anterior segment and the vitre- ous ,and several 5-7 mm trephined specimens were obtained from peripheral neuroretina-RPE-choroid complex under icebath. To flat mount specimens on Vibratomeas 150μm sheets of 50% gelatin with the choroidal side facing up,and ablate a 6.5ram area by using LASIK and PTK mode of excimer laser. The LASIK mode corrected from - 2.64D to - 4. 44D; FIX mode ablated depth from 45μm to 75μm Specimens were fixed in 4% paraformaldehyde 2-3 days ,embedded in paraffin,serially sectioned and stained with hematoxylin-eosin. Results The LASIK mode ablation might be viewed the ablated edge near the basement membrane of the RPE by correctiou -4.44D, approximately be the PTK mode ablation depth 67 Ixm;but the depth only could ablate the bulking of choroidal tissue by the LASIK mode correcting - 3.00D or the PTK mode ablating 45 Ixm. The PTK mode was easier than the LASIK mode at judgment the ablation endpoint. Conclusions To use excimer laser may obtain better neuroretina-RPE cograft sheets and avoid enzymatical methods damage to neuroretina. Both LASIK and PTK mode may ablate choroidal tissue to the need depth, however,the PTK mode is fitter for this drawing materials method. Various factors for the variability of ablation depth may be considered, including method of fixation, water content of the tissue, interindividual variability in choroidal depth.