Avastin对小鼠角膜新生血管形成和TGF-β1表达的影响

The effect of Avastin on corneal neovascularization and TGF-β1 expression in mice

目的探讨Avastin对小鼠角膜新生血管形成和转化生长因子-β1(transforming growth factor-beta1,TGF-β1)表达的影响。方法制作小鼠角膜碱烧伤模型,随机分为碱烧伤组和Avastin治疗组,碱烧伤组连续两周内每日左氧氟沙星滴眼液滴眼3次,Avastin治疗组连续两周内应用25mg/ml Avastin结膜下隔日注射5μl+每日左氧氟沙星滴眼液滴眼3次,分别于碱烧伤后3d、7d和12d取材。体视显微镜观察角膜新生血管形成情况,应用HE染色法观察角膜组织的损伤情况,采用免疫组化法观察TGF-β1在碱烧伤后不同时间段角膜组织内的表达情况。结果在不同时间段,Avastin治疗组角膜新生血管的形成均少于碱烧伤组。在正常小鼠角膜组织内,TGF-β1表达于角膜上皮层和内皮层。在碱烧伤对照组角膜内,TGF-β1主要表达于角膜上皮细胞和角膜基质内入侵的炎性细胞,在碱烧伤后3d,TGF-β1的表达达到高峰(P<0.05),在碱烧伤后12d,TGF-β1的表达恢复至正常水平。在Avastin治疗组角膜内,各时间段TGF-β1的表达均低于对照组。结论 Avastin能够抑制小鼠碱烧伤后角膜新生血管的形成,其机制可能与下调碱烧伤角膜组织TGF-β1的表达相关。

Objective To investigate the effect and possible mechanism of Avastin on corneal neovascularization, we observed the expression of TGF- β 1 in mice cornea in different stage after alkali burns. Methods The mice models with alkali burned cornea were built by sodium hydroxide. The models were divided into two groups randomly： Alkali burned group（given levofloxacin eyedrops three times a day for two weeks） and Avastin treatment group（injected 25mg/ ml Avastin 5 μl subconjunctivally once every two days as well as levofloxacin three times a day for two weeks）. Corneas were excised at the stages of 3d, 7d and 12d after alkali burns respectively. The corneal neovascularization was evaluated under stereomicroscope. Corneal injury was observed by HE stain. The expression of TGF- β 1 was observed by immunohistochemical stain. Results The corneal neovascularization was decreased in Avastin group than in Alkali burn group. In normal cornea, epithelium and endothelium showed staining of TGF- β 1 protein. In Alkali burned cornea, the expression of TGF- β 1 was detected in infiltrated inflammatory cells, corneal epithelium and endothelium. The expression level of TGF- β 1 increased and peaked at 3d after alkali burns（P〈0.05）, but decreased to normal level at the stage of 12d after alkali burns. In Avastin treatment group, the expression level of TGF- β 1 decreased at different stage comparing with corresponding Alkali burned group. Conclusion The decrease of neovascularization by Avastin in alkali burned mice cornea might be related to inhibiting the expression of TGF- β 1 in cornea after alkali burns.