SPARC基因在角膜碱烧伤中的表达

SPARC gene expressed in corneal alkali injury

目的 动态检测酸性富含胱氨酸分泌型蛋白 (SPA RC)在角膜碱烧伤中的表达 ,为探讨 SPA RC基因在角膜创伤中的作用提供依据。方法 首先建立角膜碱烧伤模型 ,并设角膜物理损伤组为对照组 ,在不同时间段提取各组角膜上皮细胞总RN A。用基因引物进行逆转录 -聚合酶链反应 (RT - PCR )扩增 ,半定量 SPA RC m RN A的表达水平。然后对 PCR扩增结果用限制性内切酶酶切验证。在取角膜上皮之前 ,对受试动物进行裂隙灯检查 ,以判断角膜碱烧伤程度与基因表达的关系。结果 (1)正常角膜上皮细胞可见 SPA RC基因的低表达 ;(2 ) SPA RC在角膜碱烧伤及物理损伤后均见较高水平表达 ,且与正常细胞表达相比较有显著的统计学差异 (P<0 .0 5) ;角膜创伤越严重 ,基因表达水平越高 ;(3 )所检测基因表达结果与显微镜观察角膜水肿、混浊、角膜新生血管等损伤结果呈同步趋势。结论 SPARC在角膜碱烧伤和创伤过程中具有高水平表达。是角膜创伤修复过程中的重要因素。

Objective To evaluate the secreted protein, acidic and rich in cysteine( SPARC) gene expression after cornea alkali injury and to determine whether there is temporal relation between chemokine expression and cornea injury. Methods First, rat models of corneal alkali injury were established. Corneal physic injury and normal nonsurgical eyes served as control specimens. Secondly, The SPARC gene expression by corneal epithelium of each experimental rat was evaluated. Total RNA was extracted from corneal epithelium, followed by the RT-PCR detection. The cDNA was semi-quantified by laser densitometry. Main products of SPARC primer RT-PCR amplification were analyzed by restricted endonuclease digestion. Before above laboratory studies, experimental corneas were examined by slit-lamp .Results (1)There was minimal expression of SPARC in normal corneal epithelium;(2)Overexpression of SPARC was observed in corneal epithelium after corneal alkali injury, there was significant statistical difference between the normal and corneal alkali injury groups ( P <0.05);(3)In the case , the tendency of overexpression in SPARC was correlated with corneal edema, clouding, neovascularization and positive findings of clinical examination. Conclusion Upregulation of SPARC mRNA expression by corneal epithelium is specifically associated with corneal chemical burn and injury.It plays an important effect during corneal wound healing.