鼠青光眼模型视网膜神经节细胞中热休克蛋白27表达的研究

目的探讨热休克蛋白27(HSP27)在鼠青光眼模型视网膜神经节细胞(RGCs)中的表达及其与血清中相应抗体的关系。方法将49只Wistar大鼠随机分为高眼压组(32只鼠)、sham对照(假手术)组(12只鼠)及正常对照组(5只鼠)。电凝鼠巩膜表面至少3组静脉及角膜缘周围血管,减少房水静脉回流,建立鼠青光眼模型。分别于术后1、2、3、4及8周分别处死大鼠。处死前测眼压,抽血2ml,供酶联免疫吸附测定使用,分析视网膜组织内HSP27蛋白抗原产生的血清中相应抗体水平。同时对鼠眼视网膜组织进行石蜡切片,采用免疫组化法检测RGCsHSP27的表达及分布情况,并对检测结果进行统计学分析。结果高眼压组右眼术后眼压明显升高,术后3d眼压(27.52±6.63)mmHg(1mmHg=0.133kPa),术后1周眼压(31.42±6.18)mmHg,此后眼压基本稳定。术后各时间点高眼压组右眼眼压与其术前、左眼及sham组右眼和左眼比较,差异有统计学意义(P<0.01)。血清中抗HSP27抗体滴度在术后1周缓慢升高,2、3周达高峰,此后逐渐下降至接近正常水平。术后2周和3周,高眼压组血清中HSP27抗体含量与sham对照组和正常对照组比较,差异有统计学意义(P<0.01和P<0.05)。RGCs中HSP27阳性表达率在术后各时间点,高眼压组右眼与左眼、sham对照组右眼和左眼及正常对照组右眼和左眼比较,差异有统计学意义(P<0.01)。RGCs中HSP27阳性表达随着眼压升高及高眼压持续时间延长逐渐增强,且视网膜神经纤维层中也出现较明显的HSP27的阳性表达。结论内源性HSP27表达增强可能在青光眼视神经病变中具有重要作用。

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 in experimental rat glaucoma model and to study the relationship between HSP27 expression and hypertension using serum autoantibodies. METHODS: 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. RESULTS: 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). CONCLUSION: Enhanced expression of endogenous HSP27 might play an important role in the development of glaucomatous optic neuropathy.