Effect of subconjunctival bevacizumab (Avastin) on experimental corneal neovascularization in guinea pigs.

PURPOSE: To evaluate the effect of subconjunctival bevacizumab (Avastin) on experimental corneal neovascularization in guinea pigs.

METHODS

Forty eyes of 40 guinea pigs were chemically cauterized with 75% silver nitrate and 25% potassium nitrate sticks. Fifteen eyes (group 1) received 2 subconjunctival injections of bevacizumab (0.1 mL, 1.25 mg) simultaneously with cauterization and 3 days later. Fifteen eyes (group 2) received 2 subconjunctival injections of bevacizumab (0.1 mL, 1.25 mg) 3 and 5 days after cauterization. Ten eyes (group 3, control group) received 2 subconjunctival injections of 0.1 mL of balanced salt solution 3 and 5 days after cauterization. After we determined the burn and neovascularization scores for all groups, the animals were killed on the 10th day. The percentages of neovascularization on the surface of the cornea were measured in terms of pixels on digital photographs. The average number of vessels at maximally vascularized areas was determined for each specimen.

RESULTS

Neovascularization score was 1.1 +/- 0.3 in group 1, 2.46 +/- 1.3 in group 2, and 3.5 +/- 0.5 in the control group. The difference was statistically significant (P < 0.001). The area of neovascularization at the cornea surface was 15.6% +/- 10.1% in group 1, 19.74% +/- 11.2% in group 2, and 23.5% +/- 7.4% in the control group (P = 0.194). The average number of neovascular vessels at group 1 was significantly reduced in comparison with group 2 and the control group (P < 0.001).

CONCLUSIONS

Subconjunctival injection of bevacizumab decreases the extent of chemically induced corneal neovascularization in guinea pigs. The antineovascular effect of bevacizumab is higher if the injection is performed simultaneously with the chemical cauterization.