Histologic Changes After Intravitreal Injection of Rapamycin and Bevacizumab in a Porcine Model

Abstract

Purpose: : To verify safety of intravitreal rapamycin, bevacizumab, and combination of both drugs studying histological changes in a porcine model.

Methods: : Eight eyes from a porcine model were included in this histologic study. The eyes were treated with 1ml intravitreal injection of bevacizumab (2.25mg/ml) in group A; intravitreal injection of balanced saline solution for group B (use as control) ; group C injected with 0.5ml of rapamycin (1mg/ml) in addition with a intravitreal injection of bevacizumab, and in group D rapamycin intravitreal injection alone. The eyes were enucleated 21 days after intravitreal injections, then tissue processing and stainig was performed with special dyes including hematoxylin and eosin, and Pearls stain.

Results: : No structural damage was detected or identified at any retinal layer of this porcine model of eyes injected with intravitreal rapamycin, bevacizumab, or even when including both drugs at the same time.

Conclusions: : Rapamycin is safe for intravitreal administration with no structural alterations and damage as reveal in the histologic findings of our study in a porcine model, neverless, we recommend electrofisiology testing and other safety-security evaluation methods before testing this drug intravitreously in humans.

Keywords: drug toxicity/drug effects • retina • clinical laboratory testing