脂质体介导内皮抑素基因转移抑制兔角膜新生血管的研究

目的　探讨阳离子脂质体介导的内皮抑素 (ES)基因转移对角膜新生血管的抑制作用。方法　新西兰大白兔 30只,角膜缝线法制作角膜新生血管模型,按随机数字表法随机分为A、B、C3组。A组:缝线后立即于上方近角膜缘处结膜下注射 150μl阳离子脂质体与ES重组质粒 (含质粒 20μg)的混合液;B组:同样部位注射 150μl阳离子脂质体与空白质粒(含质粒 20μg)的混合液;C组:同样部位注射 150μl生理盐水。分别于缝线后 3、7、14、21和 28d在裂隙灯显微镜下观察各组角膜新生血管的生长情况,并计算角膜新生血管的面积。通过免疫组化方法检测各时相角膜缘及角膜组织中ES目的基因的表达情况。结果　A组角膜新生血管的出现时间为 ( 6 85±0 69 )d,B组为(3 43±0 53)d,C组为(3 14±0 69)d, 3组间比较差异有统计学意义 (F=100 24, P<0 05 ),A组明显晚于其他两组;在缝线后 14、21、28d,A组角膜新生血管的面积均明显小于其他两组,差异有统计学意义(F=72 662, 75 601, 27 729; P均<0 05)。A组于各观察时相均可在上方角膜缘和角膜组织中发现ES阳性表达,以转染 3d时最为明显, 7d时阳性细胞着色有所变浅, 14d时阳性细胞数明显减少, 28d时只偶见阳性表达;各时相下方角膜及角膜缘组织均未见ES阳性表达。B、C两组各时相均未发现ES阳

Inhibition of corneal neovascularization by liposomes mediated plasmid encoding human endostatin

OBJECTIVE: To evaluate the effect of liposomes mediated plasmid encoding endostatin (ES) for inhibiting experimental corneal neovascularization (CNV). METHODS: Thirty New Zealand albino rabbits were sutured on the superior cornea. Animals were randomly divided into 3 groups. Different reagents were injected at each group:liposomes and plasmid encoding human ES complex in the group 1, liposomes and carrier plasmid complex in the group 2 and saline in the group 3. The occurrence and development of CNV were observed by slit-lamp microscope 3, 7, 14, 21 and 28 days after suturing, the size of CNV area was measured and calculated. Immunohistochemistry was used to detect the ES protein expression in cornea and limbus at different time points. RESULTS: The appearance time of CNV was (6.85 +/- 0.69) d in group 1, (3.43 +/- 0.53) d in group 2 and (3.14 +/- 0.69) d in group 3. Significant difference in appearance time of CNV was found between the group 1 and the others (F = 100.24, P < 0.05). No significant difference was found between the group 2 and group 3. The size of CNV areas of group 1 were significantly smaller than that of the groups 2 and 3 at every time point (F = 72.662, 75.601, 27.729; P < 0.05). ES protein expression in group 1 was detected at superior limbus and the cornea, with the highest level of expression at 3 days, gradually decreased after 7 days and had a very small quantity of expression at 28 days. ES protein expression was not detected in the groups 2 and 3. CONCLUSION: Liposomes mediated plasmids encoding ES can be transferred to cornea and limbus tissues by subconjunctival injection, with the highest levels of expression at 3 days posttransfer and can suppress corneal neovascularization at certain degrees.