摘要
目的 观察大鼠碱烧伤后角膜新生血管 (corneal neovascularization,CNV )的生长及退化过程和角膜中血管内皮生长因子 (vascular endothelial growth factor,VEGF)m RNA的变化 ,探讨两者间的相互作用。方法 建立大鼠角膜碱烧伤新生血管模型 ,利用角膜灌注和照相方法对 CNV进行观察。在不同时间点提取角膜的总 RNA ,并用半定量逆转录聚合酶链式反应 (RT- PCR)检测 VEGF m RNA。应用结膜下注射地塞米松治疗 CNV,并观察其对 VEGF表达的调节作用。结果 大鼠角膜碱烧伤后角膜新生血管的生长过程可分为 3个阶段 :(1)角膜新生血管的初期阶段 (烧伤后 2 d内 ) ;(2 )角膜新生血管的增长阶段 (烧伤后 3～ 10 d) ;(3)新生血管的退化阶段 (烧伤 2周后 )。实验发现 VEGF m RNA在烧伤后 2 4 h达到高峰 ,是正常角膜的 5 .3倍 ;在烧伤后第 4天 ,VEGF m RNA水平为正常时 1倍 ;第 7天时 ,VEGF m RNA下降至正常。地塞米松组 CNV生长与 VEGF m RNA的表达均受到抑制 ,在烧伤后 2 4 h VEGF的表达是正常时的 3.2 4倍 ,抑制率为 38.8% ;烧伤后4 d,较对照组 VEGF的表达下降了 16 .2 % .地塞米松组 CNV面积抑制率分别是对照组的2 1.7% (烧伤后第 4天 )和 2 3.7% (烧伤后第 7天 )。结论 VEGF m RNA的升高及降低同CNV的发生及退?
Objective To observe the changes of vascular endothelial growth factor (VEGF) mRNA and to study the relationship between neovascularization and VEGF in the rat corneal after cautery with sodium hydroxide. Methods In Wistar rats, the model of corneal neovascularization was set up. Corneal angiogenesis was evaluated by the perfusing method and observed with a slit lamp microscope. Total RNA was extracted from whole corneas at different times after cautery, and VEGF mRNA level was determined by reverse transcription polymerase chain reaction (RT PCR). To examine the regulation of VEGF, one group of rats were treated with dexamethasone. Results The neovascular response progresses were in three phases: (1) a latency phase preceding vessel growth(≤2 days after cautery); (2)a proliferation phase between 3 and 14 days; (3) a regressive phase (≥14 days after cautery). In corneas after cautery, VEGF 165 mRNA peaked at 24 hours, a 5.3 fold increase by 24 hours and a 1 fold increase by 4 days, and decreased to the baseline by day 7 after cautery. Dexamethasone inhibited both neovascularization and VEGF transcription. Dexamethasone inhibited 38.8% of cautery induced VEGF upregulation at 24 hours and 16% at 4th day. Dexamethasone inhibited 43.5% of area of cautery induced CNV at 4th day and 65.8% at 7th day after cautery. Conclusion The increase and decrease of VEGF correlate with the proliferation and the regression cautery induced CNV. Dexamethasone' s inhibition of CNV is associated with the inhibition of VEGF upregulation.
出处
《眼科新进展》
CAS
2002年第3期163-165,共3页
Recent Advances in Ophthalmology
基金
北京市自然科学基金资助 (编号 :7992 0 12 )~~
