Background Free-flap Epi-LASIK surgery show a fast epithelial healing and mild trauma responses.Its mechanism is notable. Objective The aim of this study was to compare the corneal epithelial healing response following photorefractive keratectomy(PRK)and flap-free Epi-LASIK surgery. Methods Twelve experimental rabbits were randomly assigned to high cutting group(-10.00 D)and low cutting group(-3.00 D),and 2 normal matched rabbits were used as controls.PRK was performed in lateral eyes and flap-free epipolis laser in situkeratomileusis(Epi-LASIK)surgery was curried out in the fellow eyes.The corneal wound healing response in early stage of post-operation was examined under the slim lamp,and the inflammatory cells infiltration in cornea,basic fibroblast growth factor(bFGF)and nuclear transcription factor(NF-KB)expressions in corneal stroma were detected by hematine-eosin staining and immunohistochemstry in the seventh day after operation. Results The inflammatory reaction was milder in the eyes with Epi-LASIK than ones of PRK under the slim lamp.No significant difierences were found in numbers of inflammatory cells in cornea.expressions of bFGF and NF-κB in corneal stroma between two types of surgeries in low cutting group(P＞0.05).In high cutting group,the numbers of inflammatory cells were(12.25±1.22)/400 field in PRK eyes,and those of free-flap Epi-LASIK eyes were(6.67±0.31)/400 field,showing obvious difference between them(t=-8.87,P＜0.01).Expressions of NF-κB(A value)in cornea were 6.11±1.36 and 41.82±8.7 1 in PRK eyes of low cutting group and high cutting group.and those in free-flap Epi-LASIK were 3.01±0.81 and 11.59±4.55.indicating a drastically increase in PRK eyes(P＜0.05).The expressions of bFGF(A value)in corneal stroma were 33.59±6.98 and 123.68±18.81 in PRK eyes and those in free-flap Epi-LASIK eyes were 69.20±8.85 and 123.68±1 8.81 in low cutting group and high cutting group,presenting a considerably decrease in PRK eyes (P＜0.05).The corneal epithelial healing was faster in free-flap Epi-LASIK eyes than that in PRK eyes.and deeper cutting slowed the healing procedure. Conclusion In low cutting group,healing time of corneal epithelium is close between PRK and flap-free Epi-LASIK.But in high cutting group,epithelial healing is faster and inflammatory reaction is lighter in flap-free Epi-LASIK compared with PRK.%背景去瓣准分子激光角膜上皮瓣下磨镶术(Epi-LASIK)术后上皮愈合快,创伤反应轻,受到眼科医师的关注.但去瓣Epi-LASIK术后上皮愈合的机制一直是目前研究的热点.目的研究兔准分子激光角膜切削术(PRK)和去瓣Epi-LASIK对不同屈光度眼切削术后早期角膜基质中炎性细胞、碱性成纤维细胞生长因子(bFGF)、核转录因子(NF-κB)的表达,探讨两种手术方式在不同切削深度时角膜创伤愈合反应的机制.方法将16只新西兰大白兔按随机数字表法分为高度切削组(-10.00 D)6只、低度切削组(-3.00 D)6只和空白对照组2只.实验组取一侧眼行PRK,对侧眼行去瓣Epi-LASIK,术后每日裂隙灯下观察活体兔角膜愈合情况.术后7 d空气栓塞法处死兔,角膜组织用苏木精-伊红染色和免疫组织化学法检测早期角膜上皮及基质中炎性细胞、bFGF和NF-κB的表达.结果裂隙灯检查表明,去瓣Epi-LASIK手术眼术后炎症反应轻于PRK眼.在低度切削组,2种术式间术后角膜炎性细胞的数量以及NF-κB和bFGF在角膜组织中表达的差异均无统计学意义(P＞0.05),而在高度切削组,PRK手术眼角膜中炎性细胞数量为(12.25 ±1.22)个/400倍视野,明显高于去瓣Epi-LASIK手术眼的(6.67±0.31)个/400倍视野,差异有统计学意义(t=-8.87,P＜0.01).角膜中PRK手术眼NF-κB的表达量(A)分别为6.11±1.36、41.82±8.71,较去瓣Epi-LASIK手术眼的3.01±0.81、11.59±4.55明显增加,而角膜中PRK手术眼bFGF的表达量(A)分别为33.59±6.98、123.68±18.81,较去瓣Epi-LASIK手术眼的69.20±8.85、123.68±18.81降低,差异均有统计学意义(P＜0.05).去瓣Epi-LASIK上皮愈合速度快于PRK组,而随着切削深度的增加,愈合速度减慢.结论在低度切削时,去瓣Epi-LASIK手术眼角膜上皮的愈合速度与PRK手术眼无明显差别,但在高度切削时,去瓣Epi-LASIK术眼角膜上皮的愈合速度稍快于PRK术眼,炎症反应程度轻.
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