[The expression of heat shock protein 27 in retinal ganglion cells in the rat glaucoma model].Zhonghua Yan Ke Za Zhi. 2005 Jun; 41(6):533-9.ZY
To observe the expression of heat shock protein 27 (HSP27) in retinal ganglion cells in experimental rat glaucoma model and to study the relationship between HSP27 expression and hypertension using serum autoantibodies.
Forty nine Wistar rats were randomly divided into ocular hypertension group, sham control group and normal control group. 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 the controls. Serum immunoreactivity against HSP27 was examined in these three groups by means of enzyme-linked immunosorbent assay (ELISA). Immunohistochemical staining for HSP27 was performed in 49 rats (98 eyes) for studying the distribution of the target gene products in retinal ganglion cells and retinal nerve fiber layer.
Electrocoagulation treatment caused a significant increase of IOP and was maintained for 8 weeks (P < 0.01), which was greater than that in the contralateral eyes, sham control eyes and normal eyes. The baseline IOP was (15.69 +/- 3.20) mm Hg (1 mm Hg = 0.133 kPa). IOP was increased to (27.52 +/- 6.63) mm Hg (3 days after the operation), (31.42 +/- 6.18) mm Hg (1 week after the operation) and stabilized thereafter for 8 weeks. Serum ELISA titers of HSP27 antibody were higher in ocular hypertension group as compared to the control groups in both sham and normal group at 2 weeks after operation (P < 0.01) and 3 weeks after operation (P < 0.05). The expression of HSP27 was significantly enhanced in RGCs with IOP elevated and sustained. It was also significantly increased in retinal nerve fiber layers (RNFL).
Enhanced expression of endogenous HSP27 might play an important role in the development of glaucomatous optic neuropathy.