丝裂霉素C和地塞米松防治LASEK术后角膜Haze的对比实验研究

Experimental study on mitomycin C and dexamethasone for preventing Haze after Laser Subepithelial Keratomileusis in rabbits

目的对比丝裂霉素C(mitomycin C,MMC)和地塞米松抑制兔眼准分子激光上皮瓣下角膜磨镶术(LASEK)后角膜上皮下雾状混浊(Haze)的疗效。方法将36只新西兰白兔随机分为三组,即MMC组,地塞米松组和生理盐水对照组,各组双眼均行LASEK。MMC组和生理盐水组分别在术中一次性应用0.02%MMC、生理盐水棉片湿敷术区60s,地塞米松组术后用0.1%的地塞米松眼液滴双眼3个月。术后早期裂隙灯显微镜观察角膜上皮的愈合,1周、1、3个月观察Haze的形成情况,并行角膜光、电镜,增殖细胞核抗原(PCNA)检查,扫描电镜检查MMC组角膜内皮细胞和晶状体。结果术后三组间上皮愈合时间差异无统计学意义(P>0.05);术后1、3个月,MMC组和地塞米松组Haze明显轻于对照组,其中MMC组最轻(P<0.05)。光、电镜及PCNA示:术后不同时期MMC组术区角膜上皮细胞和前基质细胞增殖、细胞外基质的合成均受抑制,纤维排列较整齐;而地塞米松组和生理盐水对照组角膜上皮细胞过度增生,前基质细胞增生活跃,纤维排列紊乱,细胞外基质明显增多,尤以生理盐水对照组显著。三组间均未发现严重眼部并发症。结论 MMC能有效抑制LASEK术后角膜细胞的增殖而减轻Haze,其效果优于地塞米松,且无明显毒副作用,是一种防治角膜Haze的理想药物。

Objective To evaluate the efficacy and safety of mitomycin C（MMC） and dexamethasone for preventing and curing Haze after Laser Subepithelial Keratomileusis（LASEK） in rabbits.Methods 36 New Zealand rabbits underwent bilateral LASEK were randomly divided into 3 groups.During the operation,0.02%MMC and NS were respectively placed on cornea for 1 minute in MMC group and normal sodium（NS） group.And 0.1% dexamethasone eye drops were used in dexamethasone group for 3 months after surgery.Corneal epithelial healing and Haze were observed by slit lamp microscope at the early stage,and the corneas were taken out and examined by light microscope,electron microscope and proliferating cell nuclear antigen（PCNA） at 1 week,1 month and 3 months in three groups after the operation.Corneal endothelia and lens were examined as well by scanning electron microscope in MMC group.Results The healing time of corneal epithelium had no statistical difference（P〉0.05） among 3 groups.At 1 and 3 months after the operation,the corneal Haze was significantly less in MMC group and in dexamethasone group than that in NS group,and the level of Haze was lower in MMC group（P〈0.05）.The excessive proliferation of corneal epithelial cells,the active proliferation of superficial stroma cells,chaotic fiber and over extracellular matrix were detected in ablation area by light microscope,transmission electron microscope and PCNA in NS group and dexamethasone group,and that was more obvious in NS group,whereas the proliferation of corneal epithelium and superficial stroma cells and the synthesis of extracellular matrix were prohibited remarkably in MMC group at different stage after operation,and fibers were in order.Serious complication was not observed in 3 groups.Conclusion MMC can prohibit the proliferation of keratocyte and reduce corneal Haze,and have no obvious side effects.MMC is more effective than dexamethasone on preventing corneal Haze.