角膜损伤后新生血管和神经再生的相互作用研究

Corneal injury is a common cause of blindness in Ophthalmology。Corneal neovascularization secondary to injury can not only change the corneal transparency, but also lead to significant reduction of success rate of corneal transplantation. Corneal nerve injury can induce dry eye and corneal neurotrophic keratitis, and cause neovascularization. At present, most researches eithor focused only on the inhibition of angiogenesis, or focused only on promoting nerve regeneration, less attention had been paid to the relationship between corneal neovascularization and corneal nerve growth. In this sutdy, (1 ) two kinds of animal models are established, i.e. a model with varying degrees of neovascularization after nerve injure, and a model with different degree of nerve regrowth after corneal neovascularization, using a variety of methods, mutual influence of corneal neovascularization and corneal nerve growth, as well as changes on related cytokines, are studied, to reveal the inherent interaction between corneal neovascularization and nerve growth and related molecular mechanism, and ( 2 ) donor cornea pretreatment with antiangiogenic drug are conducted by three ways, to observe the distribution of target drug in the corneal stroma, and by using a corneal neovascularization model, to observe the angiogenesis, nerve growth and expression of related molecules after transplantation, in order to provide scientific basis and new ideas for possible application of donor corneal drug pretreatment in improving success rate of high-risk corneal transplantation operation.

角膜损伤是眼科常见致盲原因。损伤所继发的角膜新生血管不但改变了角膜透明性，同时也导致角膜移植术成功率显著降低。角膜神经损伤不但可诱发干眼和角膜神经营养不良性角膜炎，并引起新生血管生长。目前，相关研究大多或只侧重抑制新生血管，或只侧重促进神经再生，较少关注角膜新生血管和角膜神经生长的相互关系。本课题（1）通过制作两种动物模型，即角膜神经损伤后伴有不同程度新生血管模型和角膜新生血管发生后伴有不同程度神经生长模型，采用多种研究方法，研究角膜新生血管与角膜神经生长的相互影响，及其相关细胞因子改变，揭示角膜新生血管与神经生长之间的内在作用和相关分子机制（2）采用三种方式进行供体角膜抗新生血管药物预处理，观察靶药物在角膜基质中的药物分布，并采用角膜新生血管模型，观察移植术后新生血管和神经生长及相关因子表达，为探讨供体角膜药物预处理在提高高危角膜移植手术成功率中的应用提供新的科学依据和新思路。

角膜盲为眼科主要致盲疾病，角膜损伤为角膜盲的重要原因之一。本研究致力于探寻角膜损伤后新生血管及角膜神经再生的相互关系，并研究抗新生血管药物对角膜移植术后新生血管及移植排斥反应的作用。.内容：1、基质层间切开法建立角膜神经损伤模型，在神经损伤的基础上辅以不同程度的新生血管生长模型，观察角膜新生血管对角膜神经损伤及再生的影响。并通过对CD11b+炎性细胞的研究，初步探索两者之间相互抑制的机理。2、建立低危及高危两种大鼠同种异体角膜移植模型，通过结膜下注射贝伐单抗及植片经贝伐单抗预处理两种用药方式，观察贝伐单抗对角膜移植术后新生血管及免疫排斥反应的作用，评价其对角膜植片存活的疗效及作用机制。.结果：1、诱导角膜新生血管术后1周、2周、4周，角膜新生血管越多、长度越长，角膜神经密度越低，较为稀疏，证实了角膜新生血管抑制角膜神经的修复，证实了两者为相互抑制的关系。2、角膜损伤后，角膜上皮下及基质层CD11b+炎性细胞随角膜新生血管的增多而增加。初步表明，角膜损伤后新生血管通过炎症反应抑制神经的再生。3、通过对角膜植片存活时间、角膜新生血管浸润面积及角膜中CD4+、CD8+免疫细胞的数量的观察，确定结膜下注射贝伐单抗可有效抑制大鼠同种异体穿透性角膜移植术后新生血管的生长，并可能通过此作用延缓移植排斥反应的发生，延长角膜植片存活时间。而植片用贝伐单抗预处理并无明显效果。贝伐单抗抑制移植排斥反应的疗效略逊于传统的激素类药物。.科学意义：通过以上研究，确立了角膜新生血管及角膜神经再生的关系，并初步探索两者之间作用的机制。明确了贝伐单抗对低危及高危角膜移植术后角膜新生血管及免疫排斥反应的作用，为临床上角膜移植排斥的治疗提供相应的科学依据。