中文摘要：

目的探讨羊膜提取液（AE）对兔PRK术后haze的影响及机制。方法实验研究。36只新西兰白兔（72只眼）用随机数字表法随机分为3个组（实验组、激素组与空白组），构建PRK动物模型，术后实验组滴用AE，激素组滴用0．1％磷酸地塞米松眼液，空白组滴用不含AE的赋形剂眼液。用裂隙灯眼前节照相记录haze的形态，荧光素钠染色观察角膜上皮的修复，TUNEL法观察角膜基质细胞的凋亡，免疫荧光法观察角膜基质细胞仪一SMA的表达。用Kruskal．WallisH检验对haze分级评分进行统计学分析，用方差分析及LSD—t检验进行多组问均数的比较，用Spearman等级相关分析对haze形成与TUNEL阳性细胞及d—SMA表达量进行相关性分析。结果72只兔眼角膜上皮均在PRK术后6d内完全修复，实验组、激素组及空白组角膜上皮平均修复时间分别为（4．12±0．62）、（5．25±0．78）及（4．96±0．73）d，组间比较差异有统计学意义（F=14．144，P〈0．01）。3个组术后l周均开始出现不同程度的haze，3～4周时尤其明显，术后8周减轻。实验组角膜haze程度与激素组和空白组比较，术后l周（H=3．995，12．77；P〈0．05）、4周（H=4．468，9．003；P〈0．01）及8周（H=4．397，5．744；P〈0．05）均较低。术后1周实验组、激素组及空白组TUNEL阳性细胞数分别为（2．2500±0．3750）、（4．5000±0．7500）和（7．1250±0．9063）个／高倍视野，实验组与空白组和激素组比较差异均有统计学意义（t=4．26，8．13；P〈0．01）；术后4周空白组仍有表达，但实验组、激素组未见明显阳性细胞表达；术后8周3个组均未见明显TUNEL阳性细胞表达。术后1—8周，仪一SMA在空白组、激素组的角膜基质浅层均有阳性表达，且2个组术后4周阳性细胞数目较1周增高，术后8周较4周的阳性细胞数目减少。术后1～8周，01．SMA在实验组均为阴性表?

英文摘要：

Objective To investigate the effects and mechanism of amniotic extraction on corneal healing after photorefractive kerateetomy （ PRK）. Methods Experimental Study. Thirty-six New Zealand rabbit corneas were performed with PRK models （ - 10 diopters, 6. 5 mm diameter）. According to random number table, all eyes were divided into three groups, including treated with amniotic extraction, 0. 1% dexamethasone and excipient respectively after operation. Clinical and histoDatholo~ic examinations were taken by slit-lamp microscope and light microscope. Corneal epithelium reparation was observed by fluorescent staining. Corneal stroma cell apoptosis was evaluated by terminal deoxyribonucleotidy transferase- mediated deoxynuridine triphophate nick end labeling （TUNEL） assay. Myofibroblast generation was evaluated by immunofluorescence checking the expression of alpha-smooth muscle actin （a-SMA）. The number of TUNEL and c~-SMA positive cells was analyzed to explore the effects on corneal haze. The haze grading was compared between groups using Kruskal-Wallis H test. Mean values for each experiment were compared between groups using a one-way analysis of variance and LSD-t test. Spearman rank analysis was used to evaluate the correlation between the haze grading and the expression of TUNEL positive cells and c~-SMA. Results The corneas of seventy-two eyes reepithelialized in 6 days after operation. The average epithelium repair time of the AE group was （ 4. 12 ＋ 0. 62 ） d, the dexamethasone group was （ 5.25 -＋ 0. 78） d, and the excipient group was （4. 96 ＋ 0. 73 ） d. The progression of reepithelialization was significantly faster in the AE group than the other two groups （ F = 14. 144, P 〈 0. 01 ）. The haze appeared in the first week after the PRK in all three groups, increased after 3 - 4 weeks, and relieved after 8 weeks. The degree of haze was significantly lower in the AE group than the other two groups in the first week （ Vs. dexamethasone group, H = 3. 995,P 〈 0. 05 ; vs. exci