Heat shock protein 27 and its role in retinal ganglion cell apoptosis in rat high intraocular pressure model / 中华实验眼科杂志

ABSTRACT

Background Glaucoma is common blinding eye diseases characterized by chronic loss of retinal ganglion cells(RGCs).Currently glaucoma pathogenesis is not completely understood,heat shock protein 27 ( HSP27 )may be associated with the pathogenesis of glaucomatous optic neuropathy. Objective Through the establishment of a rat model of high intraocular pressure,detection of the expression of HSP27 antibody in serum and RGCs apoptosis to investigate the role of HSP27 in RGCs apoptosis. Methods Fifty-one clean Wistar rats were divided into high intraocular pressure group (34 rats)and sham operation group( 17 rats)using a random number table.An animal model of high intraocular pressure was established in the right eye by the application of bipolar underwater electrocoagulation on vein of sclera surface in the experimental group,and rats with conjunctiva incision only without electric coagulation were served as sham operation (control).The intraocular pressure of rats of the both groups including experimental and control rats was measured 1,2,4,6,8 weeks after operation and then the rats were sacrificed.1 ml serum was collected from these rats to determine the concentration of HSP27 antibody.The retinas of the rats were isolated and homogenated for the extraction and analysis of the retinal protein by Western blot.Apoptosis of RGCs were assayed by TUNEL.The use of the experimental animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by Kunming Medical Collegc. Results Intraocular pressure was elevated significantly after modeling and remained a high value during the expcrimental duration,showing a significant difference among the different groups ( F =318.502,P＜0.01 ).However,no significant change in intraocular pressure before and after operation in the sham-operation group ( F =2.076,P ＞ 0.05 ).The serum concentration of HSP27 antibody was increased significantly overtime from 1,2,4,6 to 8 weeks after the surgery applied,with a significant difference among various time points( F =154.221,P＜0.01 ),but no obvious difference was seen in the shamoperation group( F =0.422,P＞0.05 ).Importantly,Apoptosis rate of RGCs in the experimental eyes was significant higher as the time prolong after intraocular elevated(x2=856.12,P＜0.05 ).The positive rate of RGCs apoptosis in the rats with high intraocular pressure group was elevated significantly compared to the rats in the sham operation group(P＜0.05). Conclusions High intraocular pressure induces the expressions of HSP27 in retina and the accumulation of HSP27 antibody in rats serum;the elevated HSP27 is associated with the increased cell death in RGCs.