Objective To observe the retinal toxicity of intravitreal injection of Bevacizumab (Avastin) in albino rabbit eyes at different doses. Methods Sixteen New Zealand albino rabbits，thirty-two eyes were divided into four groups at random. Three groups were prepared for Avastin experiment, named A, B, C. Each group received intravitreal injection of Avastin at dose 1.25 mg/0.05ml，2.5 mg/0.1ml and 6.25 mg/0.25 ml respectively. The other group named D served as a control, and accepted intravitreal injection of 0.9% normal saline 0.1 ml. Then test it by electroretinagram (ERG) after 1, 2 and 4 weeks. In addition, each group was removing two rabbitprime;s eyes to observe the retinal morphology and ultra structure by light microscope and transmission electron microscopy after intravitreal injection avastin 1, 2 and 4 weeks. Results The ERG pattern and amplitude of each group were normal after intravitreal injection Avastin 1, 2 and 4 weeks. （P＞0.05）Between study and control groups, there was no significant difference in retinal morphology which was observed by light microscope at any stage of the study. By electron microscopic observation, retinal ultramicrostructure was no evident retinal toxicity being tested both at group A and B (1.25 mg/0.05 ml and 2.5 mg/0.1 ml). But at group C (6.25 mg/0.25 ml), significant mitochondrial swelling and hydropic changes were seen in the inner segments of photoreceptors. And there was no improvement of the pathological changes in four weeks. Conclusion It is safe that intravitreal injection of Avastin in rabbitprime;s eyes at dose 1.25 mg or 2.5 mg at single time. （Chin J Ocul Fundus Dis，2008，24：193-196）
Objective To observe the effects of structure and function of cornea, chamber angle and retina of varying doses of Bevacizumab which was injected intravitreally in rabbits. Methods Twenty-four New Zealand albino rabbits were divided into three groups randomly, the right eyes in three groups received int ravitreal injection Avastin at dose 1.25 mg，2.5 mg and 5 mg respectively as experimental eye, the left eyes accepted intravitreal injection 0.9% normal saline at the same volume as a control eye. The anterior segment of eye and ocular fundus were examined and intraocular pressure was measured by slit-lamp microscope and direct ophthalmoscope before and after injection. It was tested by Electroretino gram (ERG) before and after injection 1, 4, 8 weeks. At the 8th week, it carried out corneal endothelium counting; then enucleated eyes to observe by the light microscope and transmission electron microscope. Results No statistically significant difference regard to IOP,corneal endothelium counting, a-and b-waves of ERG at any stage of study in every group（P＞0.05）. No obvious change at cornea, chamber angle, retinal structure and retinal ultrastructure in every group under light microscope. Conclusion This study indicated that there is no obvio us toxicity of intravitreal injection with Avastin 1.25~5.0 mg in normal rabbit eyes. （Chin J Ocul Fundus Dis，2008，24：189-192）