慢性高眼压状态下大鼠视网膜内神经营养因子表达的变化

Expression of retinal neurotrophin in chronic high intraocular pressure rats

目的检测高眼压状态下大鼠视网膜神经营养因子的表达变化。方法通过烙闭大鼠巩膜上静脉制作慢性高眼压模型,并对模型进行评估。应用免疫组化技术和RT-PCR检测正常大鼠和高眼压下大鼠视网膜上神经营养因子及其受体的表达水平。结果大鼠造模后1d、3d、5d、1周、2周、1个月和2个月的早晨800眼压分别为(14.387±3.527)mmHg(1kPa=7.5mmHg)、(13.833±3.473)mmHg、(13.833±3.473)mmHg、(13.388±3.473)mmHg、(14.350±2.727)mmHg、(15.310±3.495)mmHg、(15.053±3.467)mmHg,升高幅度达到基础眼压的50%以上。高眼压状态下,神经生长因子出现微弱表达,其mRNA水平及受体TrkA表达水平低下;脑源性神经营养因子在造模后2周出现较强阳性表达,并持续到造模后2个月,其mRNA水平短期增高,受体TrkB的mRNA水平降低;神经营养素-3在内核层出现阳性表达增强,mRNA水平逐渐降低,神经营养素-3受体TrkC表达水平随时间延长表达强度逐渐增加,mRNA水平一过性增高;神经营养素-4蛋白和mRNA水平在造模后都出现一过性表达增强;p75的mRNA水平低于正常大鼠。结论神经营养因子及其受体的蛋白和mRNA水平随着高眼压时间变化而相应改变,蛋白与mRNA变化趋势一致,但是神经营养因子及其受体变化的水平趋势不完全一致。

Objective To study the expression of neurotrophin in retina of chro- nic high intraocular（IOP） rats. Methods Three episcleral veins in rat eyes were can- terized to produce chronic high IOP. The neurotrophin and their receptors in retinas were measured by immunohistochemistry and RT-PCR in qualified rats. Results IOP of rats at 8：00 AM at 1 day,3 days,5 days,1 week,2 weeks,1 month and 2 months after modeling were （ 14.387 ± 3.527 ） mmHg （ 1 kPa = 7.5 mmHg）, （ 13. 833 ± 3. 473 ） mmHg, （ 13.833 ± 3.473） mmHg, （ 13. 388 ± 3.473 ） mmI-Ig, （ 14. 350 ± 2.727 ） mmHg, （ 15. 310 ± 3.495 ） mmHg and （ 15. 053 ± 3.467 ） mmHg, which were 50% higher than normal rats. Un- der high IOP,the immunostaining of nerve growth factor were faint,the level of its mR- NA and receptor Trk A were low; Brain-derived neurotrophic factor increased gradually at 2 weeks after modeling and maintained for 2 months,its mRNA transiently increased, expression of Trk B mRNA was low;Neurotrophin-3 was strong positive in inner nuclear layer apparently,but its mRNA decreased gradually; Trk C,as the receptor of NT-3 ,in- creased gradually and its mRNA was high trartsiently;Neurotrophin-4 and its mRNA ex- pressed strongly in a short time; Level of p75 mRNA was lower than normal.Conclusion The mRNA and protein of neurotrophin and their receptors changed with the time change of high IOP,the changes of protein were consistent with that of mRNA,but the changes of neurotroohin is inconsistent with their receptors.