[Retina penetration of subconjunctival ranibizumab injection in the rabbit eye].

OBJECTIVE

To investigate whether ranibizumab can penetrate into the retina after subconjunctival injection in a rabbit model.

METHODS

Experimental study. Fifty-six New Zealand rabbits were randomly divided into four groups: control group (3), saline subconjunctival injection group (3), ranibizumab intravitreal injection group (25) and ranibizumab subconjunctival injection group (25). Each rabbit received single injection in right eye. Ranibizumab's location and concentrations in the retina and aqueous humor were determined by immunofluorescence staining and ELISA at 1, 2, 4, 8, 12 weeks after injection. The comparison of ranibizumab concentration data was analyzed by t-test.

RESULTS

The concentrations of aqueous humor in intravitreal injection group, determined by ELISA, were (389.67 ± 22.55), (319.33 ± 17.93), (22.67 ± 3.06), (9.67 ± 1.53) and (7.33 ± 2.18) mg/L at 1, 2, 4, 8, 12 weeks respectively. Concentrations of subconjunctival injection group were (53.67 ± 3.21), (12.67 ± 3.06), (8.33 ± 1.53), (2.66 ± 2.08) mg/L at 1,2,4,8 weeks and had a statistical difference compared with intravitreal injection group at each time point (t = 32.96, 38.39, 7.67, 11.07, P < 0.05). But there was no detection at 12 weeks. Similar in retina immunofluorescence staining results, the ranibizumab positive signals were detected in all the time points except the last one in subconjunctival injection group.

CONCLUSION

Subconjunctival ranibizumab injection may be able to penetrate into retina.