慢性高眼压大鼠外侧膝状体硫氧还蛋白抗氧化系统的变化研究

Study of thioredoxin antioxidative system in lateral geniculate body of chronic intraocular hypertension rat

目的 研究慢性高眼压大鼠外侧膝状体硫氧还蛋白抗氧化系统的动态变化及其可能的分子调控机制.方法 采用烧灼巩膜上静脉诱导高眼压的方法建立大鼠慢性高眼压模型,有眼作为实验眼（实验组）,左眼仅分离静脉但不烧灼,作为假手术眼（假手术组）.高眼压模型大鼠共25只,4只大鼠作为空白对照组.在眼压升高后不同时间点（1、3、7、14、28 d）采用免疫印迹法和RT-PCR方法检测硫氧还蛋白Trx1、Trx2蛋白和mRNA表达以及硫氧还蛋白调控基因Txnip、Sesn2和Srxn1的表达,并按照时间进行分组.在各时间分组组内数据采用配对t检验;在各时间分组组问采用单因素方差分析.结果 大鼠高眼压3d,硫氧还蛋白抗氧化系统中硫氧还蛋白表达灰度值为0.83±0.02,较对照组（1.02±0.04）有所下降,差异具有统计学意义（F=4.871,P=0.005）;14d组,Trx1的mRNA相对表达量0.63 ±0.04,较对照组（0.96±0.03）有所下调,差异具有统计学意义（t=13.647,P＜0.05）;7 d组,上游基因Sesn2 mRNA相对表达量为0.53±0.11,较对照组（0.96±0.03）有所下降（t=13.812,P＜0.05）;7d组和14 d组Srxn1的mRNA相对表达量分别为0.71 ±0.05、0.49±0.03,较对照组（0.97±0.02、0.96 ±0.02）有所下降（7d组t=9.451,P＜0.05; 14 d组t=13.611,P＜0.01）,差异具有统计学意义.抑制基因Txinp mRNA表达分别为1.83±0.04、2.37±0.03,较对照组（1.00 ±0.02、0.95 ±0.03）有所上调,差异具有统计学意义（7 d组t=-7.924,P＜0.05,14 d组t=12.637,P ＜0.01）.结论 慢性高眼压大鼠外侧膝状体存在氧化损伤,且发生氧化损伤时外侧膝状体内Trx系统Trx1、Trx2受多途径抑制发生不同程度表达下调,其上游抑制基因表达上调,上游促进基因表达下调.

Objective To investigate the dynamic changes and molecular mechanisms of thioredoxin system in lateral geniculate body of chronic intraocular hypertension rats.Method Glaucoma model was established by cauterizingrat＇s episclera veins.Right eye is the treatment group,while left eye is the sham operation group,vein of which is just isolated not be cauterized.There were 25 rats in high intraocular pressure group,and 4 rats in control group.The expression of Trx,Trx1,Trx2,Sesn2,Srxn1,Txnip was detected by Western blot and RT-PCRat different time points after intraocular pressure rose （1,3,7,14,28 d）,and were grouped according to the time points.Paired t test was used in the data analysis within each time group and one-way ANOVA was used in the comparisons among different time groups.Result After 3 days of glaucoma induction,the gray-scale value of thioredoxin （0.83 ±0.02） was statistically significant decreased （F =4.871,P =0.005）,compared with the control group （1.02 ± 0.04）.After 14 days,TRX1 related expression level reduced to 0.63 ±0.04,while the control group level was 0.96 ±0.03（t =13.647,P 〈 0.05）.The related expression level of SESN2 was 0.53 ± 0.11,but the control group expression was 0.96 ± 0.03 （t =13.812,P 〈 0.05）.SRXN1 decreased to O.71 ± 0.05 and 0.49 ± 0.03 after 7 days and 14 days respectively,while the expression of control group were 0.97 ±0.02 and 0.96 ±0.02 respectively.（Group 7 d,t =9.451,P 〈 0.05; group 14 d,t =13.611,P 〈 0.01）.On the contrary,expression of TXINP was upregulated to 1.83 ±0.04 and 2.37 ±0.03 respectively,while the expression of control group were 1.00 ±0.02 and,0.95 ± 0.03 （Group 7 d,t =7.924,P 〈0.05;14 d t =12.637,P〈0.01）respectively.Conclusions Oxidative stress existed in lateral geniculate body of chronic intraocular hypertension rat model,and the down-regulated expression of Trx,Trx2 of the Trx system in lateral geniculate body was inhibited by multiple pathways when oxidative damage occurs.The inhibitor genes on up-stream increased while promoting genes diminished.