The Expression Of Heat Shock Protein 27 In Retinal Ganglion Cells In The Rat Glaucoma Model

Objective: To observe the expression of heat shock protein 27 (HSP27) in retinal ganglion cells (RGCs) in experimental rat glaucoma model and study the relationship of HSP27 expression with serum autoantibody. Methods: 49 Wistar rats were divided into the ocular hypertension group , Sham control group and normal control group in random. Intraocular pressure(IOP) was elevated by electrocoagulation of at least 3 episcleral and limbal veins in the right eye of each rat Contralateral eyes were used as controls. Serum immunoreactivity agaist HSP27 was examined in three groups by means of enzyme-linked immunosorbent assay (ELISA). Immunohistochemical staining for HSP27 was performed for 49 rats (98 eyes) in attempt to show the distribution of the target gene products in RGCs and retinal nerve fiber layer (RNFL). Results: Electrocoagulation treatment caused a significant IOP increase. The baseline IOP was 15.69±3.20 mm Hg. 3 days after operation IOP was 27.52 ±6.63 mm Hg; 1 week after operation IOP was 31.42 ± 6.18 mm Hg and stabilized thereafter to 8 weeks. Serum ELISA titers of HSP27 antibody were higher in ocular hypertension groups compared with control groups in both sham and normal groups at 2 weeks after operation(p<0.001); at 3 weeksafter operation(p<0.05). The expression of HSP27 was significantly enhanced in RGCs with IOP elevated and sustained, and it was also more significant in RNFL. Conclusion: The enhanced expression of the endogenous HSP27 might play an important role in glaucomatous optic neuropathy.