Morphological Observation Of The Effects Of Beavcizumab On Retinal Neovascularization In Rat Models

Objectives To evaluate the efficacy of intravitreal different dosage of Bevacizumab for the treatment of retinal neovascularization in rat models.Methods One hundred and twenty 7-day-old SD rats were divided into eight groups in random that include normal group, hyperxia group, Bevacizumab treatment group, and BSS control group. Seven groups except normal were put into the environment with 75%oxygen for 5 days to establish models of vascular proliferation retinopathy. The three experimental groups were given Bevacizumab by inteavtreal injection at the dose of 1μl, 5μl, 10μl. The other three experimental groups were given BSS by inteavtreal injection at the dose of 1μl, 5μl, 10μl. The last group without any treatment . At the age of 17 days, at which time 3 rats from each group were sacrificed and assessed for retinal neovascularization with injection of Evans Blue. The remaining rats from each groups were killed and assessed for retinal neovaseularization by Hematoxylin and Eosin Staining, retinal neovascularization was quantified by counting Pre-retinal endothelial cells.Results1 Neovascularization counting: In the normal group ,the number of pre-retinal endothelial cells was (1.08±0.38). In groups BSS control and hyperxia ,there are (31.97±0. 26),( 32. 08±0. 31),( 31.59±0.79) and (31. 32±0.61)cells, which showed no significant difference between them(p>0.05), and significant difference in number of pre-retinal endothelial cells was found between normal group and hyperxia group(p<0.01). The number of nucleolus of vascular endothelial cells on the surface of retina were (14.27±1.25) (9.86±0.93) and (6.58±0.87) in the experimental group of Bevacizumab 1μl,5μl and 10μl. There was significant difference between the normal group and Bevacizumab group(p<0.01). Significant difference was also found between three groups treating with Bevacizumab.2 Retinal observation: retinal examination revealed significant retinal neovascular, especially in vitreous cavity, leakage and enlarged non-perfusion regions in the perimeter of the retina in experimental groups of hyperxia and BSS, while normal group had no change. Significant reduced of retinal neovascular was observed in groups with treatment of intravitreal Bevacizumab. Experimental group of 1μl Bevacizumab appears no difference with the naked eyes, and neobascular in vitreous cavity almost disappeared in experimental group of 5μl and 10μl Bevacizumab.3 There was no significant differences in each SD rat's change in weight.4 Irnmunohistochemical staining for factor CD34 proved endotheliocyte to be vessels.Conclusions1 Hyperxia can induce the production of retinal neovascularization in SD rat models.2 Intravitreal injection of Bevacizumab can arrest retinal neovascularization in SD rat models ,and better with the more Bevacizumab.3 There was no other side effect has been found if we used in short term.