Avastin和地塞米松在大鼠角膜新生血管中的作用

Effects of avastin and dexamethasone on rat corneal neovascularization

目的探讨眼表应用avastin、地塞米松及联合用药对SD大鼠角膜新生血管(CNV)的作用及机制。方法建立碱烧伤诱导大鼠CNV模型,分为4组:地塞米松组给予质量分数0.1%地塞米松局部点眼;avastin组给予5.0g/Lavastin;联合组给予5.0g/Lavastin+0.1%地塞米松;对照组给予生理盐水。采用裂隙灯观察、免疫组织化学染色等方法观察各组CNV的面积和血管内皮生长因子(VEGF)的表达。结果第6天时,对照组CNV生长接近高峰,血管粗大、密集,交织成网状;地塞米松组和avastin组CNV较短,血管稀疏、细长;联合组CNV较短,血管较稀疏、细小。实验后3、6、12d,3个组CNV面积比较差异均有统计学意义(F=145.659,P=0.000;F=296.370,P=0.000;F=148.008,P=0.000),组间多重比较显示avastin组、地塞米松组及联合组CNV面积均小于对照组,差异均有统计学意义(P<0.01)。Avastin组与地塞米松组间差异无统计学意义(P>0.05)。第7天时,组织病理学检测显示对照组角膜可见大量炎性细胞浸润,基质层大量CNV,胶原纤维排列紊乱;地塞米松组、avastin组角膜基质排列趋于整齐,CNV明显减少,腔小且分布稀疏,未见大量炎性细胞浸润;联合组基质层胶原纤维排列规则,CNV显著减少,炎性细胞浸润较少。免疫组织化学检测提示对照组角膜全层VEGF表达明显增强,其表达部位主要分布在CNV区域和上皮全层。地塞米松组和avastin组CNV密度减低,角膜基质层CNV区域的VEGF表达减少;联合组CNV密度明显减低,VEGF表达微弱。结论 Avastin和地塞米松均能抑制CNV,二者联合用药具有协同作用,可降低CNV和炎性细胞浸润。

Background A variety of factors are related with corneal neovascularization（CNV）,and vascular endothelial growth factor（VEGF） plays the regulative role in the forming process of CNV.Objective This study attempted to investigate the effect of topically administered agents avastin,dexamethasone and drug combination on experimental CNV and its mechanism in rats.Methods CNV animal models were induced by putting the 3 mm filter paper soaked 1 mol/L NaOH solution at the center cornea for 30 seconds in 48 clean SD rats.20 μL of avastin （5 g/L）,20 μL of dexamethasone （0.1%）,avastin＋dexamethasone and 20 μL of 0.9%NaCl were topically applied respectively in 12 models at 5-minute interval for 12 days.The growth of CNV was observed under the slit lamp,and the CNV area was calculated.Hematoxylin-eosin staining of cornea samples was performed for the pathological examination on the seventh day after experiment.Expression of VEGF in CNV was detected by immunohistochemistry.Results In 12 days after experiment,corneal new blood vessels were dense and thicker in 0.9% NaCl solution group,but in 0.1% dexamethasone group and avastin group,the corneal new blood vessels were sparse and thinner.Less corneal new blood vessels were seen in avastin＋dexamethasone group.The area of CNV was smaller in 0.1% dexamethasone group and avastin＋dexamethasone group and avastin group in 3,6 and 12 days after experiment in comparison with 0.9% NaCl solution group （all P0.01）.The area of CNV was significantly decreased in avastin group compared with 0.1% dexamethasone group and avastin＋dexamethasone group in various time points （all P0.01）.No significant difference in CNV area was found between 0.1% dexamethasone group and avastin group （P0.05）.Infiltration of lots of inflammatory cells and vascular canals were seen in 0.9% NaCl solution group,but little of inflammatory cells and vascular canals were in dexamethasone group,avastin group and avastin＋dexamethasone group.Immunohistochemistry revealed that the expression of VEGF was mainly in CNV zone and corneal epithelial layer.Expression of VEGF was more in 0.9% NaCl group compared with dexamethasone group and avastin group,and that in avastin＋dexamethasone group was weaker.Conclusion Topical application of avastin and dexamethasone can inhibit alkali-induced CNV.Avastin and dexamethasone show a synergistic effect in suppressing the expression of VEGF and inflammation cells.