大鼠角膜碱烧伤后黏附分子变化的研究

目的 探讨大鼠角膜碱烧伤后不同时期ICAM-1、VCAM-1和CD44在角膜的表达和分布，了解与角膜碱烧伤病理损害的关系，完善角膜碱烧伤免疫机制的研究。方法 Wistar大鼠80只，制备角膜中度碱烧伤动物模型。分别于角膜碱烧伤后8h、1天、3天、1周、2周、4周、7周处死大鼠，分别采用链酶亲和素-过氧化物酶法（SABC法）和RT-PCR方法检测大鼠角膜局部ICAM-1，VCAM-1和CD44的表达。结果 碱烧伤3天组角膜上皮细胞ICAM-1和VCAM-1呈强阳性，角膜上皮细胞和角膜缘的毛细血管内皮细胞CD44呈中度阳性。2周组角膜上皮细胞ICAM-1表达减弱，基质细胞仍呈强阳性，角膜上皮细胞、基质细胞和基质内新生血管内皮细胞VCAM-1和CD44呈中度表达。碱烧伤3天组ICAM-1和VCAM-1 mRNA表达量增加，差异显著，CD44 mRNA表达量无显著变化。碱烧伤2周组ICAM-1 mRNA量均较3天时明显减少，两者有显著差异（P〈0．01），VCAM-1 mRNA表达量增加，比3天时增多，同正常对照组相比差异极显著（P〈0．001），CD44 mRNA表达量增加，同正常对照组相比差异显著（P〈0．01）。结论 ICAM-1、VCAM-1和CD44在角膜碱烧伤的不同阶段其表达不同。急性期ICAM-1和VCAM-1的抗原表达和mRNA合成增加，说明角膜碱烧伤的炎性反应重，预后差。随病程延长，CD44 mRNA表达量逐渐增加，证明CD44及其配体在角膜碱烧伤的愈合过程中发挥重要作用。

Variety of adhesion molecules following corneal alkali burns in the rat

Objective To observe the expression and distribution of ICAM-1,VCAM-1 and CD44 following alkali burns in the rat cornea and to find out the relationship between adhesion molecules and pathologic reaction of ocular alkali burns.Methods To induce the models of alkali burns in Wistar rat.The animals were sacrificed at 8 h,1 d,3 d,1,2,4 and 7 weeks after burn.The corneas were excised and subjected to immunohistochemical staining by incubating with monoclonal antibodies against ICAM-1,VCAM-1 and CD44 in SABC procedures.Total RNA was isolated from the excised cornea and mRNA level of ICAM-1,VCAM-1,CD44 was detected by RT-PCR.Results The strong expression of ICAM-1 and VCAM-1 and moderate expression of ICAM-1 was observed in the corneal epithelial cells and keratocytes at 3 days.The expression of ICAM-1 at epithelial cells decreased but strong expression of ICAM-1 at keratocytes was still observed at 2 weeks.Moderate expression of VCAM-1 and CD44 was observed in the corneal epithelial cells,keratocytes and limbal vascular endothelial cells at 2 weeks.The mRNA level of ICAM-1 and VCAM1 was increased at 3 days following alkali burns and there was significant difference compared to the control(P<0.01).There was no change in CD44 mRNA level at 3 days.At 2 weeks,the level of ICAM-1 mRNA was lower than that at 3 days(P<0.01),and that of VCAM-1 and CD44 increased significantly.Conclusion The expression of ICAM-1,VCAM-1 and CD44 are different during the alkali burns.It offers an experimental prove to treat the corneal alkali burns by modulating the expression of the adhesion molecules.