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目的 探讨准分子激光屈光性角膜切削术 (photorefractivekeratectomy ,PRK)后凋亡机制介导的角膜创伤愈合反应对屈光度数回退和角膜雾状混浊 (haze)的影响 ,以及局部应用锌制剂的药物效果。方法 对 90只新西兰白兔行双眼PRK ,将左眼作为实验眼 ,手术前、后分别给予A组 0 1%地塞米松眼液、B组 0 5 %硫酸锌眼液和C组 0 0 4 %丝裂霉素眼液滴眼 ;右眼作为对照眼。术后定期裂隙灯下观察haze的程度 ,测量角膜的厚度 ,进行光镜和透射电镜观察 ,采用脱氧三磷酸尿苷缺口末端标记法行凋亡细胞检测 ,并进行对比性分析。结果 (1)PRK术后角膜前基质细胞出现凋亡 ,实验眼B组凋亡细胞最少 (P <0 0 1)。 (2 )术后角膜厚度增加 ,前基质细胞增多 ,实验眼haze和增生程度较低 ,其中实验眼B和C组最低 (P <0 0 1)。 (3)术后角膜上皮增生 ,实验眼B组角膜上皮厚度最小(P <0 0 1)。结论 PRK术后屈光度数回退和haze的形成是凋亡机制介导的角膜创伤愈合过程 ,锌制剂可阻止角膜前基质细胞凋亡 ,最大限度减轻反应性过度增生 ,有望成为临床防治haze形成和屈光度数回退的理想药物
Objective To investigate the effect of corneal wound healing reaction on photorefractive keratectomy (PRK) after laser photorefractive keratectomy (PRK) on regression of refraction and corneal haze, as well as the effects of topical application of zinc agents effect. Methods 90 eyes of New Zealand white rabbits underwent PRK. The left eye was used as the experimental eye. Before and after the operation, group A received 0 1% dexamethasone eye drops, group B 0 5% zinc sulfate eye drops and group 0 0 4 % Mitomycin eye drops; right eye as a control eye. The degree of haze was observed under regular slit lamp and the thickness of cornea was measured. The light and transmission electron microscopy were used to observe the apoptosis. The apoptotic cells were detected by gap junction labeling with deoxyribo-triphosphate (UDT) and compared with each other. Results (1) Apoptosis of prekeratal stromal cells was observed after PRK, and the apoptotic cells in the experimental group B were the least (P <0.01). (2) The thickness of cornea increased, the number of anterior stromal cells increased, and the degree of haze and hyperplasia in experimental eyes was lower. The lowest in experimental eyes was in groups B and C (P <0.01). (3) Postoperative corneal epithelial hyperplasia, corneal epithelial thickness in experimental group B was the smallest (P <0.01). Conclusions PRK postoperative refractive index regression and haze formation are apoptotic mechanism-mediated corneal wound healing process. Zinc preparation can prevent pre-keratinocyte apoptosis and minimize reactive hyperplasia, which is expected to become a clinical control haze formation and Refraction of the ideal medicine to roll back