多次大剂量贝伐单抗结膜下注射抗兔眼小梁切除术后瘢痕化研究

背景贝伐单抗是第一个完整长度的人抗血管内皮生长因子（VEGF）单克隆抗体，已作为抑制新生血管的药物而广泛用于眼科临床。然而，作为小梁切除术后抑制伤口及滤过泡的纤维化及抗血管生成的药物，贝伐单抗多次大剂量使用的安全性和有效性尚待评估。目的评估大剂量贝伐单抗结膜下多次注射抗小梁切除滤过术后滤过泡瘢痕化的安全性及有效性。方法采用自身双眼配对的研究设计。对新西兰白兔18只36只眼行小梁切除术滤过手术，动物左眼在术后即刻及术后第3、5、7天于滤过泡结膜下注射25g／L贝伐单抗0．1ml，右眼术后不进行注射作为对照眼。术后间隔2d裂隙灯下观察滤过泡形态并根据Moorefield滤过泡分级系统进行分级。分别于术后第10、20、30天各摘除12只眼球行苏木精一伊红染色评估细胞的性质，用Masson染色评估成纤维细胞化程度，并以抗血管性血友病因子（anti-vWf）免疫组织化学染色评估每组兔眼的血管化程度。结果与对照组相比，贝伐单抗治疗眼的滤过泡大且更为弥漫，术后第7天贝伐单抗治疗组与自身对照组眼滤过泡面积分别为（2．48±0．22）cm。和（1．73±0．27）em。，差异有统计学意义（t=5．194，P〈0．05）。贝伐单抗治疗眼的滤过泡生存天数（21．O¨0±1．56）d与对照组（12．50±1．97）d相比明显延长，差异有统计学意义（P=0．005）。组织学及免疫组织化学分析证实，与对照组相比，在术后20d时，贝伐单抗治疗眼的滤过泡及邻近组织结膜的血管化程度明显减少，2组间vWf阳性染色吸光度值的平均差值为14320．7±4134．9，差异有统计学意义（t=12．275，P〈0．05）；而术后30d时贝伐单抗治疗眼的成纤维细胞沉积明显减少，2组间成纤维细胞阳性染色面积的平均差值为0．27±0．03，差异有统计学意义（t=15．980，P〈0．05）。结论兔眼小梁切除术后多次结膜下注射贝伐单抗可有效地延长滤过泡的生存时间，在术后30d贝伐单抗能减轻滤过泡和邻近结膜组织的血管化程度。此外，贝伐单抗在术后滤过泡及邻近组织血管化的末期可显著抑制成纤维细胞介导的组织增生。

Anti-scar effect of bevacizumab by multiple-time and high-dose subconjunctival administration following trabeculectomy in rabbits

Background Bevacizumab is primarily aimed at pathologic angiogenesis for off-label uses such as the treatment of ocular neovascular disorders.However,as a new anti-fibrotic and anti-angiogenic agent following trabeculectomy,the safety and efficacy of bevacizumab by multiple-time and high-dose subconjunctival injection are still under study.Objective This study was to assess the safety and efficacy of bevacizumab after multiple-time and high-dose subconjunctival injections.Methods Regular trabeculectomy filtration surgery was performed on both eyes of 18 clean New Zealand White rabbits 0.1ml of bevacizumab(25g/L) was subconjunctivally injected intraoperatively and 3,5,7 days postoperatively in the left eyes of rabbits,and no any intervene in the right eyes were as normal controls.Bleb morphology was examined every 2 days and graded based on Moorefield's criteria and compared between the bevacizumab-treated eyes and normal saline(NS) eyes.The animals were sacrificed at 10,20 and 30 days after surgery respectively.The histopathological changes of the blebs were detected by hematoxylin and eosin stain to evaluate the cellular element around the bleb,and Masson stain was used to assess the degree of fibroblast proliferation.The degree of vascularity of bleb was identified by anti-vWf stain.Approval of this protocol was obtained and permitted from People's Hospital Institutional Animal Care and Use Committee of Peking University.The use of experimental animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Compared to the NS-treated eyes,bevacizumab-treated eyes showed the larger and more diffusely elevated blebs with the significant difference(2.48±0.22cm2 versus 1.73±0.27cm2,t=5.194,P＜0.05).The survival time of the filtration bleb in bevacizumab panel was longer in bevacizumab-treated eyes compared to control eyes,showing a significantly difference between them(21.0±1.56 days versus 12.5±1.97 days,t=3.830,P=0.005).Histological and immunohistochemical analysis confirmed that bleb and adjacent conjunctiva vascularity(A value) was significantly less in bevacizumab-treated eyes than that in control eyes at 20 days after surgery with the difference value 14320.7±4134.9(t=12.275,P＜0.05),and fibroblast deposition value was evidently diminished after bevacizumab treatment at 30 days following surgery in comparison with control eyes with the mean difference 0.27±0.03(t=15.980,P＜0.05＝.Conclusion Repeated subconjunctival injection of bevacizumab can effectively prolong the survival time of bleb in a rabbit model of trabeculectomy and limit the degree and area of vascularization in 30 days following surgery.Bevacizumab inhibit fibroblast-meditated tissue formation significantly in the later phase of vascularization after trabeculectomy.