色素上皮衍生因子对视网膜X射线损伤的保护作用

Protective effects of pigment epithelium-derived factor against X-ray-induced retinopathy

本文通过体内外实验研究了色素上皮衍生因子(Pigment epithelium-derived factor,PEDF)对X射线引起视网膜损伤的保护作用。通过PEDF受体抑制剂处理和siRNA转染人视网膜色素上皮细胞系ARPE-19来抑制PEDF功能,逆转录荧光定量PCR与ELISA测定siRNA降低PEDF表达的效果,CCK-8实验测定X射线照射后细胞活力的变化,采用小动物放射治疗模拟定位机设左右两野对穿照射小鼠眼部,每野照射10 Gy X射线,总剂量为20 Gy,配制含2 nmol/L PEDF-34(PEDF第44~77位的34个氨基酸片段)的生理盐水溶液,照射后每天滴眼处理小鼠,连续4周,照射8周后取眼球进行苏木素伊红(HE)染色与TUNEL染色,观察视网膜病变和细胞凋亡情况。体外实验表明,预处理PEDF受体抑制剂和降低PEDF表达可增强X射线对ARPE-19细胞的损伤作用,PEDF-34对X射线引起的ARPE-19细胞损伤具有保护作用。小鼠实验表明,20 Gy X射线照射后8周视网膜色素上皮细胞层出现结构异常,外核层含有凋亡细胞,PEDF-34处理组保持了视网膜的正常结构且并无凋亡细胞。本研究提示:PEDF在X射线引起的视网膜辐射损伤中具有保护效果,PEDF-34滴眼可缓解视网膜X射线损伤,为研究防治放射性视网膜病变的新方法提供了实验依据。

The protective effects of pigment epithelium-derived factor(PEDF)against X-ray-induced retinopathy were investigated in vitro and in vivo.The function of PEDF was suppressed using PEDF receptor inhibitors and transfection of siRNA in human retinal pigment epithelium cell line ARPE-19.The decreased expression of PEDF was measured using quantitative fluorescent reverse transcription PCR and ELISA.Cell viability after X-ray exposure was monitored using the CCK-8 method.Both left and right irradiation fields were set up to deliver X-rays to the eyes of mice using a small animal radiotherapy simulation machine.Each field was irradiated with 10 Gy.The total dose was 20 Gy.The saline containing 2 nmol/L PEDF-34,a 34-amino acid fragment at positions 44~77 of the PEDF,was prepared.After irradiation,the mice were treated with eye drops every day for 4 weeks.After 8 weeks,the eyeballs were harvested for HE and TUNEL staining and checked for retinopathy and apoptosis.The results showed that pretreatment via PEDF receptor inhibitors and the reduction of PEDF expression aggravated X-ray-induced cell damage in ARPE-19 cells,while PEDF-34 exerted protective effects against X-ray-induced cell damage.Eight weeks after irradiation with a dose of 20 Gy,the experimental mice demonstrated aberrant morphology in the retinal pigment epithelial cell layer and apoptotic cells in the outer nuclear layer.The PEDF-34-treated group maintained a structurally normal retina and had no apoptotic cells.The current study indicates that PEDF has a protective effect against radiation-induced retinopathy,and the PEDF-34-containing eye drops could alleviate the injury.Our findings may provide an experimental basis for a new treatment approach for radiation retinopathy.