色素上皮衍生因子在人晶状体上皮细胞表达的意义

目的:观察色素上皮衍生因子(PEDF)在人晶状体内的分布,探讨人晶状体上皮细胞(LEC)中PEDF表达水平与年龄及白内障发生发展的关系。方法:收集老年性和先天性白内障患者术中所取前囊膜、新鲜眼库眼透明晶状体样品,冰冻切片标本用间接免疫荧光组织化学法检测PEDF蛋白在人晶状体中的分布,前囊膜标本分别用蛋白质免疫印迹(Western-blot)及逆转录聚合酶链反应(RT-PCR)技术检测LEC中PEDF蛋白和基因的表达水平。结果:人晶状体中存在PEDF蛋白,主要分布于前囊下LEC胞浆中。按透明晶状体、轻度白内障、重度白内障及年龄分组分析,人LEC内PEDF基因及蛋白的表达水平在晶状体由透明变混浊、混浊由轻变重的过程中呈下调趋势(P<0.01),且随着机体的衰老显著下降(P<0.01)。结论:人LEC中PEDF表达随晶状体衰老和白内障发生发展显著下调。

Expression of pigment epithelium-derived factor in human lens epithelial cells and its correlated factors

AIM:To observe the expression of pigment epithelium-derived factor (PEDF) in human lens, and discuss the correlation between the level of PEDF in human lens epithelial cells(LEC) and some lens-related pathophysiological conditions.METHODS: Lens anterior capsules attached with LEC were collected from cataract surgeries in patients with senile and congenital cataract. Human clear lens were obtained from eye bank. PEDF expression and location were detected in above frozen sections specimens by indirect immunofluorescence with polyclonal antibodies specific to human PEDF. Anterior lens capsules with LEC were respectively pooled, and grouped as following: clear lens, slight opacity, severe opacity, young and aged. In each group, PEDF protein levels were analyzed by Western-blot,and mRNA levels were determined by RT-PCR.RESULTS: PEDF protein was present in human lens, with mainly cytoplasmic expression in LEC. We firstly revealed the down-regulation of PEDF mRNA and protein levels in LEC, with the appearance and aggravation of senile cataract (P<0.01), and in aged cases as compared with young ones(P<0.01).CONCLUSION: The expression level of PEDF in LEC down-regulates with lens aging,cataract formation and progression.