Abstract: ［Abstract］ Objective〖HTSS〗〓Alternative complement pathway plays important roles in the pathogenesis and development of choroidal neovascularization(CNV). Complement factor B(CFB), an essential factor for the alternative complement pathway, has been considered as a target to block the activity of complement. In this study, we aim to investigate the inhibitive effects and the potential mechanism of recombinant CFBsiRNA in the CNV.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Fortyfive Brown Norway rats were randomly divided into: blank control(n=15), subject to no treatment; control group(n=15), which was subject to CNV induction by laser photocoagulation, followed by administration of normal saline(0.5 μL) via caudal vein injection one day before the expression peak of CFB, and test group, which was subject to laser photocoagulation to induce CNV, followed by administration of CFBsiRNA(0.5 μL/75 μg) via caudal vein injection one day before the expression peak of CFB. The injection of normal saline and CFBsiRNA was performed every two days for thrice. Fundus fluorescein angiography(FFA) was performed on day 3, 7, 14, 21, and 28 after laser photocoagulation. Photocoagulation score was determined according to the leakage of the fluorescein, based on which to detect the growth of CNV. Expression of CFB, VEGF, and BFGF in the retina and the choroid was measured using immunohistochemical method.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓FFA showed that the difference of CNV incidence between the experimental group and the experimental group was statistically significant at 7, 14, 21 and 28 days after photocoagulation（P＜005）. In the blank control, the expression of CFB, VEGF, and BFGF in the retina and choroid was comparatively lower as revealed by immunohistochemical method. For the expression of CFB, peak value was obtained 3 days after photocoagulation in the experimental and control group, followed by downregulation of CFB. Low content of CFB was still detected 7 days after photocoagulation, while the expression was stable from day 14 to day 28. In the control group, significant upregulation was observed in the BEGF and BFGF 7-14 days after photocoagulation, and reached the peak value on day 21 after photocoagulation. In the experimental group, downregulation of BFGF and BFGF was noticed on day 14, 21, and 28 after photocoagulation.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Administration of CFBsiRNA via caudal vein inhibits the progression of CNV through prohibiting CFB expression, blocking the alternative complement pathway, and downregulating the expression of VEGF and BFGF in the pathogenesis of CNV.

Key words: choroidal neovascularization, complement factor B, vascular endothelial growth factors