大鼠慢性高眼压模型视神经磷酸化tau蛋白的表达及其意义

目的探讨磷酸化tau蛋白在正常大鼠及慢性高眼压模型视神经的表达及意义。设计实验研究。研究对象Sprague-Dawley（SD）大鼠43只。方法适应性驯养3天,连续测量3天眼压,计算正常值范围,剔除平均眼压高于或低于正常值者,40只大鼠用于高眼压模型制作。右眼为实验眼,左眼为对照眼。结扎实验眼4条巩膜上静脉建立慢性高眼压模型,其中14只在实验过程中死亡,5只眼压始终不升,余下21只术后眼压升高,将其按随机数字表法分为高眼压7天组（10只）和高眼压14天组（11只）。Tono-pen XL眼压计测量术前、术后即刻、3、7、14天麻醉状态下的眼压。术后7天和14天摘取实验眼和对照眼的眼球（带视神经约0.5 cm）,行冰冻切片,免疫组织化学染色检测视神经taupS396]的表达,激光共聚焦显微镜采集图像,Image pro plus6.0图像分析软件对图像进行分析。主要指标眼压,磷酸化tau蛋白的表达（积分光密度）。结果实验眼的平均眼压在术后即刻达到高峰,约为术前的2倍,术后3天约为术前的1.5倍,维持1周后缓慢下降,且与对照眼的眼压比较有显著性差异（P〈0.01）。实验眼和对照眼的视神经均存在taupS396]的表达,术后7天、14天实验眼较对照眼表达显著增多（P〈0.01）并伴有异常聚集现象,实验眼术后14天较术后7天表达减少（P〈0.05）。结论异常过度磷酸化的tau蛋白可能参与了慢性高眼压视网膜神经节细胞轴突的损害过程,青光眼可能具有与神经退行性疾病相似的神经细胞损害机制。

Expression and significance of phosphorylated tau protein in the optic nerve of chronic ocular hypertension rats model

Objective To observe the expression and significance of phosphorylated tau protein in the optic nerve of nomal and chronic ocular hypertension rats model.Design Experimental study.Participants 43 Sprague-Dawley（SD）rats.Methods Three rats whose average intraocular pressure（IOP） was above or below the normal range were excluded after adaptive domestication and succes-sive measurement for 3 days.Chronic ocular hypertension model was established by ligating four episcleral veins in 40 rats.14 rats died during the experiment,the IOP of 5 rats did not elevated.The remaining 21 rats whose IOP was increased were randomly divided into two groups： one group enucleated at 7 days after IOP elevating（10 rats）,and another group enucleated at 14 days after IOP elevat-ing（11rats）.Tono-pen XL tonometer was used to measure IOP at the time before and right now after operation,and also 3 days,7 days,14 days after the operation.The optic nerve samples were harvested for observing the expression of TaupS396]in the normal and model eyes by immunohistochemistry at 7 days or 14 days respectively.The immunohistochemistry image was acquired with laser scan-ning confocal microscopy,then analyzed with Image pro plus 6.0.Main Outcome Measures IOP,the expression of Tau pS396]（inte-grated optical density）.Results The IOP of experimental eyes instantly reached a peak after operation and significantly higher than that of the control group（P0.01）,and then gradually decreased after 7 days.The positive expression of TaupS396]was detected in all the normal and model eyes.Compared with control eyes,the expression of Tau pS396]was increased at 7 days,and decreased at 14 days（P0.05）.Conclusions Abnormal hyperphosphorylation of tau protein may play a role in the axon damage of retinal ganglion cells dur-ing the exposure of chronic ocular hypertension,and glaucoma may share a common mechanism with the damage of neuronal cells in neurodegenerative diseases.