重组人角质细胞生长因子-2对兔碱烧伤模型角膜上皮损伤的治疗作用

Therapeutic effects of kertinocyte growth factor-2 on corneal epithelial wound healing in rabbit model of alkali burn

目的:研究外用旋滴重组人角质细胞生长因子-2(KGF-2)对兔碱烧伤模型角膜上皮损伤的治疗作用,为角膜上皮损伤的早期治疗探索新方法。方法:制备兔角膜碱烧伤模型,60只日本大耳白兔随机分为碱烧伤对照组和KGF-2组(25mg·mL-1)(n=30);各组日本大耳白兔于造模后以50μL药物滴眼,每日3次。7和14d裂隙灯观察角膜烧伤面积以及角膜新生血管的形成,MTT法检测角膜上皮细胞活性,免疫组化方法进行病理组织学检查。结果:碱烧伤后7和14d,KGF-2组角膜烧伤面积小于碱烧伤对照组,差异有显著性(P<0.01)。碱烧伤对照组7d角膜新生血管发生率为17.50%,KGF-2组为7.32%;碱烧伤对照组14d角膜新生血管发生率为41.67%,KGF-2组为32.50%。MTT检测结果显示:碱烧伤后7和14d,KGF-2组492nm吸光度与碱烧伤对照组比较差异有显著性(P<0.05或P<0.01)。碱烧伤后7和14d,病理切片HE染色显示:对照组角膜基质水肿,板层纤维排列松散、紊乱,炎症反应反复出现,角膜上皮层变薄,部分脱落,角膜内皮层内侧有大量成纤维细胞增生;KGF-2组碱烧伤后7d,角膜上皮细胞生长良好,基质轻度增厚,无明显的炎症反应;碱烧伤后14d,未出现炎症复发,角膜上皮细胞生长良好,排列整齐,角膜基质仅有轻度增厚。结论:外用旋滴25mg·mL-1KGF-2可加速角膜上皮损伤的恢复,减轻角膜烧伤的各种炎症反应症状;减轻角膜基质水肿和纤维化,同时KGF-2亦表现出显著的抑制角膜新生血管形成的作用;KGF-2有可能成为另一个对角膜上皮损伤具有重要调控作用的生长因子。

Objective To study the therapeutic effect of topically applied keratinocyte growth factor-2（KGF-2）in vivo on corneal epithelial wound in rabbit model of alkali burn and explore new methods of treatment in the early of corneal epithelial wound.Methods A 6 mm diameter epithelial defect was made in the center of rabbit corneas by the alkali-soaked filter paper.A total of 60 Japanese white rabbits were randomly divided into two groups（n=30）：KGF-2 group（25 mg·L-1）and control group.A 50 μL aliquot of 25 mg·L-1 recombinant human KGF-2 was then applied topically three times a day.The same volume of phosphate-buffered saline（PBS）vehicle was applied to the control.Each corneal epithelial defect was subsequently photographed with a slit lamp on day 7 and 14 after burn and was measured by a computer-assisted digitizer.Corneal neovascularization in two groups was observed every day.The viability of corneal epithelial cells was assessed by MTT assay;meanwhile,the corneal epithelium was examined by morphometric and histological analysis.Results There were statistically significant differences in the epithelial defet area on day 7 and 14 between KGF-2 and control groups（p0.01）.The differences in corneal neovascularization（CNV）between KGF-2 and control groups were also evident on day 7 and 14,the average percentages of CNV in KGF-2-group were 7.32% and 32.50%,whereas the rates in control group were 17.50% and 41.67%,respectively.On day 7 and 14 after wounding,there were statistically significant differences in the mean 570 nm absorbances between KGF-2 and control groups（P〈0.05 or P〈0.01）.Histological examination showed that the corneal lesions consisted of stromal edema,keratocyte loss,inflammatory cell infiltration,and CNV.Corneal epithelium cell desquamation,stromal edema and numerous neutrophil infiltrations were present in the corneal stroma in control group.In contrast,the KGF-2 group exhibited no corneal stroma inflammation,only mild stromal edema remained in KGF-2 corneas on day 14 and the significant changes of the re-epithelialization in KGF-2 group were observed.Conclusion Topically applied 25 mg·L-1 KGF-2 can accelerate corneal epithelial wound healing,in contrast to the control,and reduce inflammation,stromal edema,and fibrosis.In addition,it also exhibites significant inhibition on CNV.KGF-2 maybe become another important growth factor in the regulation of corneal epithelial wound healing.