兔眼SBK、LASIK、PRK术后角膜转化生长因子β、α-平滑肌肌动蛋白的表达及创口愈合机制的对比研究

Expression of transforming growth factor-β, α-smooth muscle actin and wound healing characteristics of rabbit cornea after sub-Bowmans leratomileusis, photorefractive keratectomy, laser in situ keratomileusis

背景目前对飞秒激光前弹力层下角膜磨镶术（SBK）术后创面愈合的研究较多，关于新型角膜板层刀SBK方面的研究尚少。观察术后早期成纤维细胞的活化程度，可以了解术后不同时间的角膜细胞增生情况。目的检测转化生长因子（TGF-β和α-平滑肌肌动蛋白（α-SMA）的表达，比较SBK、准分子激光屈光性角膜切削术（PRK）和准分子激光角膜原位磨镶术（LASIK）手术后早期角膜细胞增生活化情况以及角膜创面的愈合特点，探讨不同手术方式术后组织愈合机制及生物力学差异。方法新西兰白兔27只，用随机数字表法分为SBK组、LASIK组和PRK组，每组9只，均取右眼为手术眼，左眼为正常对照。于术后7d、1个月、3个月取兔眼角膜，光学显微镜下观察，并行免疫组织化学法检测角膜组织中TGF-β及α-SMA的表达，计数成肌纤维细胞活化数量。结果SBK组术眼角膜瓣创口边缘上皮细胞增生明显，成肌纤维细胞数量增多，术后7d创口周围TGF-β及α-SMA呈阳性表达，1个月达高峰，3个月减弱。与LASIK组相比，SBK组和PRK组TGF-β的表达差异均有统计学意义（SBK组：t=2．226、2．158、2．330，P〈0．05；PRK组：t=4．745、6．524、6．293，P〈0．05）；成纤维细胞数量的差异亦均有统计学意义（SBK组：t=4．439、5．692、4．175，P〈0．05；PRK组：t=6．330、6．723、5．267，P〈0．05）。SBK组各时间点TGF-β的表达量均低于PRK组，差异均有统计学意义（t=4．691、5．527、4．399，P〈0．05）；α-SMA的表达差异亦均有统计学意义（t=9．637、10．282、8．197，P〈O．05）；成纤维细胞数量除3个月时差异无统计学意义外，其余时间点SBK组活化均较PRK组少，差异均有统计学意义（t=5．188、4．529，P〈0．05）。结论与传统LASIK相比，SBK手术的创面活化的成肌纤维细胞、TGF-β和α-SMA表达增多，其愈合反应更强，具有更好的术后生物力学优势，但同PRK相比仍有差距。

Background There are a lot of studies about the wound healing charateristics of cornea after SBK with femtosccond laser. In our study,mechanical microkeratome was preferred for corneal flap. We observed the proliferation of keratocytes by investigating the myoflbroblast （MF） activity. Objective The study was to compare the morphologic and histological changes in the cornea after sub-Bowmans keratomileusis （SBK） with photorefractive keratectomy （PRK） and laser in situ keratomileusis （LASIK） by investigating the express of transforming growth factor-β（TGF-β） and a-smooth muscle actin（c^-SMA） and to investigate the wound healing characteristics of cornea after SBK. Methods Twenty-seven aduh New Zealand white rabbits were randomly assigned into group A, B and C. SBK was performed on the right eyes of each rabbit in group A,LASIK for group B and PRK for group C. All the left eyes were used as the normal control group. Histological examinations by light microscopy were performed on day 7,1 months, 3 months after surgery. The expression of α-SMA and TGF-β and the number of activated MF were assessed by immunohistochemistry. Results In SBK group,corneal epithelium cells proliferation around the wound was seen and the numbers of active fibroblasts were increased after surgery. The expression of α-SMA or TGF-β around the corneal flap and the corneal stroma started at day 7 postoperatively and peaked at 1 months and decreased at 3 months.