title: Testing toxicity of multiple intravitreal injections of bevacizumab in rabbit eyes.
abstract: OBJECTIVE
  To evaluate the potential toxicity of repeated intravitreal injections of bevacizumab in rabbit eyes.
  
  
  METHODS
  Randomized, placebo-controlled experimental animal study.
  
  
  METHODS
  Fourteen chinchilla rabbits; 12 assigned to the experimental group and 2 assigned to the normal control group.
  
  
  METHODS
  Three sequential, biweekly, intravitreal injections of bevacizumab in doses of 2.5 mg/0.1 mL or 5.0 mg/0.2 mL were performed on each rabbit. Evaluations included intraocular pressure (IOP), aqueous flare, B-scan ultrasound, fundus photography, ultrasound biomicroscopy, electroretinography (ERG), and visually evoked potentials (VEPs) performed at baseline and during the follow-up period. The eyes were enucleated at 1 week and 4 weeks after the last intravitreal injection, and underwent light and electron microscopic evaluations, as well as testing for apoptotic activity.
  
  
  RESULTS
  After intravitreal injections, no changes were found by regular clinical observation and IOP tests. There was no significant difference in the anterior chamber inflammatory activity evaluated by the laser flare meter. No evidence of retinal toxicity was seen after intravitreal bevacizumab at doses of 2.5 and 5.0 mg by either ERG or flash VEPs. Electron microscopy did show the presence of inflammatory cells and some ultrastructural changes in the photoreceptor cells in the 5.0 mg experimental group 1 week after the third injection. Mild to moderate apoptosis of photoreceptors was detected in the 5.0 mg group at the same time.
  
  
  CONCLUSIONS
  The biweekly, multiple intravitreal injections of bevacizumab did not result in evidence of toxicity in regular clinical and functional observations at both 2.5 mg and 5.0 mg doses. The 5.0 mg dose may induce transient inflammation, ultrastructural abnormalities, and apoptosis.
authors.affiliation: Eye Research Institute of Shanghai JiaoTong University, Department of Ophthalmology, Shanghai First People's Hospital of Shanghai Jiaotong University, Shanghai, China.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Xu
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Fenghua
authors.initials: F
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.forename: Wenqiu
authors.initials: W
authors.lastname: Wang
authors.forename: Jin
authors.initials: J
authors.lastname: Qian
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Sun
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000633:toxicity*; D061067:Antibodies, Monoclonal, Humanized; D017209:Apoptosis / Q000187:drug effects; D000068258:Bevacizumab; D004596:Electroretinography / Q000187:drug effects; D005074:Evoked Potentials, Visual / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D007267:Injections; D007429:Intraocular Pressure / Q000187:drug effects; D033401:Microscopy, Acoustic; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000648:ultrastructure; D019233:Retreatment; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors*; D014822:Vitreous Body
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab