Expresstion of the TOLL-like receptor 4 in rat retina with chronic ocular hypertention

Abstract

Background TLR-4 is a natural immunity receptors in immunity,and it plays an important role in the repair of central nervous system damage.But its effect in glaucoma optic nerve injury is unclear.Objective This study was to investigate the expression of TLR-4 in retina with high intraocular pressure(IOP)in genetic and Drotein level and therefore explore the mechanism of TLR-4 on retinal ganglion cells(RGCs)injury. Methods Chronic ocular hypertension models were established in the right eyes of 150 clean purebred Sprague-Dawley rats by cauterizing the 3 sallow sclera veins.IOP was measured before and after 2 h,1 day,3,7,14,28,56 days after operation by PEN Ⅱ TONO-type pen tonometer.The expression of TLR-4 protein in rat retina was detected by immunohistochemistry and Western blot,and expression of TLR-4 mRNA was assayed by real time-PCR.This experimental procedure foliowed the Statement of Association for Research in Vision and Ophthalmology. Results The IOP was elevated in various time points after operation in experimental group,showing significant differences in comparison with control group(P<0.01).The immunohistochemistry revealed that the expression of TLR-4 protein in rat retina with chronic hypertension in 2 h,1 day,3,7,14,28,56 days after operation with the high A298 values in comparison with control eyes(P<0.05-0.01).Increased levels of TLR-4 mRNA in rat retinas were detected by RTPCR in high IOP eyes compared with control eyes in all time points after operation,presenting statistically significant differences between two groups(P<0.05-0.01).Western blot detection displayed the high expression of TLR-4 in retina in high IOP eyes early after operation with statistically significant results between model group and control group (P<0.05-0. 01). Conclusion TLR-4 is up-regulated in rat retina with chronic high IOP,suggesting that TLR-4 plays an immunoregulatory effect in glaucomatous eye. Key words: Intraocular pressure; Retinal ganglion ceils; Toll like receptor-4