| Objective To investigate the safety of intravitreal injection of bevacizumab in rabbits and observe the efficacy of clinical application.Methods(1)Twenty-four New Zealand albino rabbits were divided into three groups: 1.25mg/0.05 ml group,2.5mg/0.1 ml group,5 mg/0.2 ml group.Each concentration was injected in the right eye and the same volume of sterile balanced saline solution was injected into the contralateral eye of each rabbit.The examinations with slit-lamp biomicroscope and direct ophthalmoscope were performed once daily in a week after injection,then once weekly.Intraocular pressuer(IOP)were measured with Keeler tonometer at 1,2,4,8weeks after injection.Electroretinogram(ERG)were performed before the drug treatment and at 1,4,8 weeks.Corneal endothelium counting were carried out 8 weeks.The enucleated eyes were prepared for histologic evaluation of cornea,chamber angel,retinal and at 8weeks.To analyze the data of intraocular tension,the count of cerato-endothelial cell and ERG by SPSS 11.5,t test and ANOVA were used for statistical analysis of the data.(2)24 eyes of 21 patients with neovascular glaucoma in Tianjin medical university eye center were noted from April 2007 to December 2007.Regression of the iris neovascularization(INV)and IOP were observed after intravitreal injection of bevacizumab.(3)27 eyes of 24 patients with proliferative diabetic retinopathy in Tianjin medical university eye center were noted from April 2007 to December 2007.Regression of the retinal neovascularization(RNV)and intraoperative bleeding were observed after intravitreal injection of bevacizumab,intraoperative electric coagulation were noted,χ~2 test and descriptive statistical method were used for analysis of the data..Results(1)Common observation:there were 2 eyes with subconjunctival hemorrhage and 4 eyes with subconjunctival hydrops in control eyes of three groups;There was 1 eye with subconjunctival hydrops in experimatal eyes of 1.25mg group;There were 1 eye with subconjunctival hemorrhage and subconjunctival hydrops in experimatal eyes of 2.5mg group;No complications was observed in experimatal eyes of 5mg group.(2)IOP:There was no significant difference in IOP in each time point of observation during the course of the study in each group(P＞0.05).(3)ERG:There was no significant difference in a-wave,b-wave amplitude ratio of Experimental eye and control eye among groups(P＞0.05).The waveforms of ERG was normal.(4)Comeal endothelium counting:Endothelium counting between experiment eye and control eye in each group showed no statistically significant differences(P＜0.05).(5)Lightmicroscopy:The Structure of cornea,and chamber angel retinal were normal in all eyes.Electronmicroscopy:Ultrastructure of retina were normal in all eyes.(6)Regression of the INV:The INV regressed completely in 6 eyes(25%)at 1 day after injection,19 eyes(79.2%)at 1 week,23 eyes at 1 month.At 2-3months,the INV recurred in 6eyes.IOP:There was significant difference in intraocular pressure of pre-injection and 2weeks after injection in 14 eyes(P＜0.05).(7)Regression of the RNV:The RNV regressed obviously in 4 eyes withⅣstage PDR no accompany with vitreous hemorrhage at 1 week after injection.Less intraoperative bleeding was observed when vitrectomy were performed.There was significant difference in the ratio of the use of electric coagulation between this study and a large sample,retrospective study in our hospital(P＜0.05)。Conclusion:(1)This study showed that there was no significant ocular toxicity in normal rabbit eyes intravitreally injected Avastin up to 5 mg.Clinically,patients are treated with 1.25mg/0.05ml dose of Avastin and the general vitreous cavity of human is three times that of rabbit,so it is safe for patients.(2)INV regressed rapidly with the treatment of the intravitreal injection of bevacizumab;IOP of most patients can be controlled within normal.It is nesesery to improve the ischemia condition of retina with PRP timely. (3)RNV regressed rapidly with the treatment of the intravitreal injection of bevacizumab;Less intraoperative bleeding was observed when vitrectomy were performed.Intravitreal injection of Bevacizumab can be as a Surgical Adjuvant in the Treatment of PDR.
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