Development of bioactive substance delivery system to the vitreous and retina with biodegradable hydrogels

研究了IFN联合葡聚糖对实验性脉络膜新生血管（CNM）的靶向和抑制作用。干扰素(IFN) β与葡聚糖结合，葡聚糖具有金属螯合，二乙烯三胺五乙酸（DTPA）残基。基于金属配位，在含有Zn^<2+>的水溶液中简单地将IFNβ与dtpa -葡聚糖结合。研究IFNβ对人脐静脉内皮细胞（HUVECs）和牛视网膜色素上皮细胞（BRPECs）增殖的影响。为了评价IFNβ缀合物对HUVECs的活性损失，将其与IFNβ缀合物对HUVECs的作用进行了比较。用含碱性成纤维细胞生长因子的明胶微球在兔视网膜下注射诱导实验性CNV。给CNV家兔静脉注射750万国际单位(MIU)/kg /天的游离IFNβ（持续4周），IFNβ- dtpa -葡聚糖偶联物含有7.5（持续2周）或0.75（持续4周）MIU/kg /天的IFNβ，或生理盐水。通过荧光素血管造影和组织学评价这些物质的作用。为了观察偶联物的积累，采用酶联免疫吸附法测定了IFNβ在CNV组织中的剂量。IFNβ抑制huvec的生长，促进brpec的增殖。该偶联物似乎保留了大约44%的IFNβ活性。虽然两种剂量的ifn β- dtpa -葡聚糖均能抑制兔CNV的进展，但较长时间低剂量的ifn β- dtpa -葡聚糖对CNV的进展具有持续的抑制作用（P<0.05）。组织学研究显示ifn β- dtpa -葡聚糖对CNV的进展有抑制作用。该偶联物延长了IFNβ的血浆半衰期，使IFNβ在家兔体内积累CNV。

Targeting and inhibitory effects of IFN combined with dextran on experimental choroidal neovascularization (CNM) were studied. Interferon (IFN) β was conjugated to dextran, which has metal-chelating, diethylenetriaminepentaacetic acid (DTPA) residues. Based on metal coordination, conjugation of IFNβ with DTPA-dextran resulted from simply mixing both substances in an aqueous solution containing Zn^<2+>. The effects of IFNβ on the proliferation human umbilical vein endothelial cells (HUVECs) and bovine retinal pigment epithelial cells (BRPECs) were evaleated. To evaluate the activity loss of IFNβ by conjugation, the effect of the conjugate on HUVECs was compared with that of IFNβ. Experimental CNV was induced by subretinal injection of gelatin microspheres containing basic fibroblast growth factor in rabbits. The rabbits with CNV were intravenously treated twice weekly with 7.5 million international units (MIU)/kg per day free IFNβ (for 4 weeks), with IFNβ-DTPA-dextran conjugate containing 7.5 (for 2 weeks) or 0.75 (for 4 weeks) MIU/kg per day IFNβ, or with saline. The effects of these substances were evaluated by fluorescein angiography and histology. To observe the accumulation of conjugate, the doses of IFNβ in CNV tissues were measured by enzyme-linked immunosorbent assay. IFNβ inhibited the growth of HUVECs and enhanced the proliferation of BRPECs. The conjugate seemed to preserve approximately 44% of IFNβ activity. Although both doses of IFNβ-DTPA-dextran inhibited progression of CNV in rabbits, longer term administration of a lower dose of IFNβ-DTPA-dextran had a sustained inhibitory effect on progression of CNV (P<0.05). Histologic studies revealed the inhibitory effect of IFNβ-DTPA-dextran on progression of CNV. This conjugate prolonged the plasma half-life of IFNβ and enabled IFNβ to accumulate the CNV in rabbits.