Antiscarring effect of intraoperative bevacizumab in experimental glaucoma filtration surgery.

Purpose: To determine the effects of bevacizumab and mitomycin C alone and in combination on intraocular pressure and the scarring process after modified glaucoma filtration surgery in rabbits.

Methods: The rabbits underwent modified glaucoma filtration surgery and were allocated into three groups to receive intraoperative treatment with subconjunctival bevacizumab (group A), mitomycin C and subconjunctival bevacizumab (group B), or mitomycin C (group C). Intraocular pressure was measured immediately preoperatively and on postoperative days 8, 14, 17, 21, 26, and 30. The scarring process was assessed 30 days after surgery by tissue section using hematoxylin and eosin, Masson's trichrome, and picrosirius. Expression of vascular endothelial growth factor (VEGF) was assessed by immunohistochemical analyses. All analyses were performed by a masked observer.

Results: Animals in group A had higher intraocular pressure than those in groups B and C (p<0.01). Intraocular pressure did not differ significantly between groups B and C. The amount of fibrosis was similar with all stains used: group A had the highest level of fibrosis compared with groups B and C (p>0.05). There was less VEGF expression in group A than in groups B and C (p<0.01). Groups B and C did not differ in VEGF expression.

Conclusion: Mean intraocular pressure and fibrosis were lower in animals receiving bevacizumab in combination with mitomycin C but did not differ from values in animals receiving mitomycin C alone. Inhibition of VEGF was greater when bevacizumab was used alone than when bevacizumab was combined with mitomycin C.