Anti-scar effect of bevacizumab by multiple-time and high-dose subconjunctival administration following trabeculectomy in rabbits / 中华实验眼科杂志

ABSTRACT

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.