核黄素—紫外线A胶原交联对角膜胶原纤维重塑及生物力学稳定性的影响

发布时间：2018-09-10 11:30

【摘要】：目的以核黄素-紫外线A角膜胶原交联（corneal collagen cross-linking，CXL）术后兔眼角膜基质细胞和胶原纤维作为观察对象，通过了解CXL术后角膜基质细胞和胶原纤维的变化规律，探讨角膜胶原纤维重塑在CXL术后生物力学稳定性的作用；初步评价CXL治疗进展期圆锥角膜的安全性、有效性。 方法1.健康新西兰白兔15只，随机分为3组，右眼行CXL手术，左眼为正常对照，分别于术后1d、7d、4w取兔眼角膜，行HE和a-SMA染色、TUNEL法检测细胞凋亡。2.对CXL术后角膜行苦味酸天狼星红染色和角膜应力-应变测量，记录CXL术后胶原蛋白成分的变化、最大载荷、最大应力和弹性模量。3.选择13例(22只眼)进展期圆锥角膜,接受CXL治疗，于术前和术后1月、3月、6月和12个月复查，检查指标包括视力、角膜地形图、角膜活体共焦镜和角膜内皮计数等。 结果1.正常角膜基质主要为致密结缔组织，角膜基质细胞散在分布于其中。CXL术后1d，术区基质中仅偶见基质细胞，角膜上皮细胞和基质细胞均可见大量凋亡细胞。术后7d，角膜基质细胞水肿、数量减少，角膜基质细胞和上皮细胞凋亡数量均较术后1d减少。术后4w，角膜基本保持正常厚度，角膜基质细胞和上皮细胞凋亡数量显著减少。术后7d和4w，角膜基质见部分细胞a-SMA染色呈阳性。2.正常角膜基质可见分布均匀、以红色为主的I型胶原，其间可见少量纤细、绿色的Ⅲ型胶原；术后7d，Ⅲ型胶原纤维明显增多，且纤维明显变粗；术后4w，Ⅲ型胶原纤维显著增多粗大，与I型胶原间杂分布。CXL术后不同观察时期角膜的弹性模量均较正常对照组增加。CXL术后1d横向比纵向弹性模量增加的量有统计学差异。3.圆锥角膜患者接受CXL术后12个月裸眼视力和最佳矫正视力分别较术前提高0.115±0.158LogMAR单位和0.114±0.218LogMAR单位。术后12个月Kmax值和散光分别较术前降低1.893±3.713D和0.117±1.488D。角膜厚度术后1月时减少27.5±26.8μm，术后12个月时角膜厚度与术前相比无统计学显著性差异。术后角膜内皮、眼压、晶状体和眼底无明显变化。 结论1.CXL术后兔眼角膜基质细胞主要通过凋亡途径明显减少，周围基质细胞通过增殖补充凋亡的基质细胞的丢失，新生基质细胞通过活化形成成肌纤维细胞参与到角膜基质的重塑。2.CXL术后角膜各型胶原比例、分布发生改变，，提示角膜基质胶原纤维发生重塑，CXL可以长期增加角膜的生物力学强度，其效应的维持可能与胶原纤维的重塑有关。3.CXL可以阻止进展期圆锥角膜病变发展，在1年的随访期内可观察到视力和角膜地形图的指标的改善，CXL将是治疗进展期圆锥角膜一个安全有效的方法。
[Abstract]:Objective to investigate the changes of corneal stromal cells and collagen fibers in rabbit eyes after riboflavin-ultraviolet A corneal collagen cross-linking (corneal collagen cross-linking,CXL). To investigate the role of corneal collagen remodeling in biomechanical stability after CXL and to evaluate the safety and efficacy of CXL in the treatment of advanced keratoconus. Method 1. Fifteen healthy New Zealand rabbits were randomly divided into 3 groups. The right eye underwent CXL operation and the left eye was the normal control. The cornea of the rabbits were taken at 1 day, 7 days and 4 weeks after operation. Apoptosis was detected by HE and a-SMA staining with Tunel. Sirius red staining and corneal stress-strain measurement were performed on the cornea after CXL. The changes of collagen composition, maximum load, maximum stress and modulus of elasticity were recorded after CXL. Thirteen cases (22 eyes) of advanced keratoconus were selected and treated with CXL. They were reexamined before and after operation at 1 month, 3 months, 6 months and 12 months. The examination indexes included visual acuity, corneal topography, corneal confocal lens and corneal endothelium count. Result 1. The normal corneal stroma was mainly dense connective tissue. Corneal stromal cells were scattered in the corneal stromal cells. Only stromal cells were occasionally seen in the stroma of the operation area. A large number of apoptotic cells were found in corneal epithelial cells and stromal cells. On the 7th day after operation, the number of corneal stromal cells decreased and the number of corneal stromal cells and epithelial cells apoptosis decreased. After 4 weeks, the corneal thickness remained normal, and the number of corneal stromal cells and epithelial cells apoptosis decreased significantly. At 7 days and 4 weeks after operation, some of the corneal stroma cells were positive for a-SMA staining. The normal corneal stroma was evenly distributed, with a small amount of fine and green type 鈪

本文编号：2234311