色素上皮源性因子基因转染对巨噬细胞诱导大鼠增生性玻璃体视网膜病变的抑制作用及其机制

Inhibitory effects of pigment epithelium-derived factor gene transfection on proliferative vitreoretinopath induced by macrophages in rats and its mechanism

目的：探讨玻璃体腔注射色素上皮源性因子（PEDF）基因真核表达载体在增生性玻璃体视网膜病变（PVR）模型眼内的表达及作用，阐明PEDF基因转染对巨噬细胞诱导的鼠增生性玻璃体视网膜病变的抑制作用。方法：采用阳离子脂质体包裹pcDNA3-PEDF，注射到36只SD大鼠玻璃体腔内（每组大鼠的右眼为实验眼，左眼作为阴性对照眼），大鼠分为PVR对照组（仅在玻璃体腔内注射巨噬细胞诱发PVR形成）、盐水对照组（在玻璃体腔内注射生理盐水3d后注射巨噬细胞）和转染组（在玻璃体腔内注射脂质体、pcDNA3-PEDF混合物，3d后注射巨噬细胞），每组12只，应用检眼镜和全视网膜镜观察各组大鼠玻璃体和视网膜情况；HE染色光镜下观察各组大鼠玻璃体、视网膜各层结构和细胞增殖情况。结果：检眼镜和全视网膜镜观察各组大鼠PVR形成情况，玻璃体腔注射巨噬细胞后，与转染组比较，PVR对照组和盐水对照组大鼠可见玻璃体腔内增殖明显。于注射后1周见PVR对照组和盐水对照组开始出现条索样增殖，2～3周时增殖逐渐加重，并开始出现视网膜隆起，4周见全部模型眼均有明显增殖改变，有条索状增殖物牵引网膜，并出现牵拉网脱；转染组大鼠中仅1眼见玻璃体牵拉，视网膜浅脱离，余眼玻璃体无明显混浊，眼底清晰，视网膜平伏。HE染色，转染组大鼠绝大部分实验眼视网膜各层细胞结构清晰，仅发生了视网膜浅脱离的1眼可见视网膜前增殖膜，伴少量炎性细胞浸润；PVR对照组和盐水对照组大鼠玻璃体腔内可见随病程进展的炎症反应，炎症细胞聚集、成纤维细胞增殖、瘢痕形成最终导致眼球萎缩。结论：大鼠玻璃体腔注射转染PEDF可以明显抑制巨噬细胞诱导的PVR形成和发展。

Objective To investigate the expression and function of intravitreal injection of pigment epitheliumderived factor （PEDF） gene eukaryotic expression vector in proliferative vitreoretinopath （PVR） model eye, and to clarify the inhibitory effect of PEDF gene transfection on PVR induced by macrophages in rats. Methods The pcDNA3-PEDF with cationic liposome was injected into vitreous of 36 SD rats （the right eye of each rat as the experimental eye and the left eye as the negative control eye）. The rats were divided into PVR control group （injecting macrophages in the vitreous cavity to induce PVR）, saline control group （injecting macrophages 3 d after intravitreal injection of saline） and transfection group （injecting macrophages 3 d after intravitreal injection of liposome and pcDNA3-PEDF）, and there were 12 rats in each group. Then the ophthalmoscope and fundus pre set lens were used to observe the vitreous and retinal conditions of the rats in each group; the stuctures of the vitreous and retinal layers and the cell proliferation of the specimens of the rats in various groups were detected by HE staining under light microscope. Results The ophthalmoscope and fundus pre-set lens results showed that after intravitreal injection of macrophages, there was more significant vitreous proliferation in PVR control group and saline control group compared with transfection group 1 week after injection, there was vitreous proliferation in PVR control group and saline control group. 2--3 weeks after injection, the proliferation was gradually increased and retina began to detach in PVR control group and saline control group. 4 weeks after injection, there was significant proliferation in all model eyes, and traction retinal detachment occurred in PVR control group and saline control group. Only one eye of the rats in transfection group showed vitreous traction and shallow retinal detachment, and the other eyes were normal. The HE staining and light microscope results showed that the structurs of retina cells of most eyes were clear, only one eye occured shallow retinal detachment with epiretinal membrane proliferation and small amount of inflammatory cell infiltration in transfection group. There was inflammatory response with the progression of the disease, accumulation of inflammatory cells, proliferation of fibroblasts, and formation of eyeball atrophy in PVR control group and saline control group. Conclusion PEDF transfected by intravitreal injection in rats＇ eyes can significantly inhibit the formation and development of PVR induced by macrophages.