Abstract:

Objective To investigate the effects of bevacizumab on prevention of corneal neovascularization in a rat model of penetrating keratoplasty, and to evaluate its effect on the survival of corneal grafts. Design Experimental studies. Participants Fifteen F344 rats were used as donor and 30 Lewis rats as recipients. Methods After penetrating keratoplasty, recipients were randomly divided into three groups: control group(GA), bevacizumab group (GB) and dexamethasone group (GC).  A single dose of 40 μl  bevacizumab was injected subconjunctivally in GB at 0, 3, 6 and 9 days after operation. GC were subconjunctivally injected with 20 μl dexamethasone. GA was not treated. Grafts were examined every three day for two weeks by slit-lamp biomicroscopy, the rejection index (RI, edema, opacity, neovessels) and neovessel invasion area (IA) were calculated. After 14 days, the rats were killed and the expression of CD4+ and CD8+ cells in corneal grafts was detected by immunofluorescence. Main Outcome Measures Neovessel invasion area, grafts survival time and cell counting of CD4+ and CD8+. Results Seven days after surgery, IA in GA differed significantly from GB (P=0.00) and GC (P=0.01) , but GB and GC were closed to each other. At Day 7, IA was 22.50±3.67mm2(GA), 14.21±2.79mm2 (GB) and 15.38±0.84mm2(GC) respectively;  at Day 14, IA was 27.96±0.50mm2(GA), 18.76±2.73mm2 (GB) and 23.74±2.14mm2(GC) respectively. The corneal grafts survival in GB and GC was longer than GA (all P=0.000). The corneal grafts survival was 8(GA), 11(GB),13(GC) days respectively. At Day 14, the CD4+, CD8+ cells in GA were higher than GB and GC (all P=0.000). The number of CD4+ cells was 13.2±2.94(GA), 6.14±1.07(GB) and 3.5±1.78(GC) respectively. The number of CD8+ cells was 14.4±2.44(GA), 4.5±1.51(GB) and 3.38±1.68(GC) respectively. Conclusions Subconjunctival administration of bevacizumab may effectively inhibit neovascularization and corneal graft rejection. But bevacizumab is less effective than dexamethasone on inhibiting corneal allograft rejection. (Ophthalmol CHN, 2017, 26: 101-105)

Key words: bevacizumab, penetrating keratoplasty, rejection, rat