Apoptosis and electroretinogram after intravitreal injection of methotrexate in an experimental rabbit model

Abstract

The aim of this study was to explore the changes in electroretinogram of rabbit retina and apoptosis in methotrexate-induced toxicity. Rabbits were divided into 5 groups. Group I served as control in which saline solutions was injected intravitreally. Methotrexate (800 μg, 1.76 μmol) was injected into the vitreous of both eyes of rabbits groups II, III, IV and V by an insulin injector with a 26 gauge needle under general anesthesia. Retinal function was assessed by electroretinogram (ERG) after 2, 4, 10 days and one month then animals were decapitated. The eyes were enucleated and processed for DNA fragmentation studies by gel electrophoresis to retinae and measurement of caspase-3 activities. The results indicated a significant reduction (p ˂ 0.05) in a- and b-wave, a time-dependent appearance of the typical ladder pattern of internucleosomal fragmentation, a characteristic of apoptosis and increase of relative caspase-3 activity after methotrexate intravitreal injection. Methotrexate lead to apoptosis, increase of caspase-3 and affect retinal function.

A comprehensive review of intravitreal immunosuppressants and biologicals used in ophthalmology

“…6 Eman et al showed a significant reduction in a-wave and b-wave on electroretinogram (ERG), raised relative caspase-3 activity and typical ladder pattern of internucleosomal fragmentation on gel electrophoresis (characteristic of apoptosis) on injecting 800 μg/0.1 mL MTX into the vitreous cavity. 7 Single intravitreal injection of 400 and 800 μg of MTX did not show significant anti-inflammatory effects in experimentally induced uveitis in rabbits. 8 However, Deng et al 9 found intravitreal MTX to be better than dexamethasone in reducing inflammation in experimentally induced bacterial endophthalmitis with Staphylococcus epidermidis in rabbits.…”

“…6 Eman et al showed a significant reduction in a-wave and b-wave on electroretinogram (ERG), raised relative caspase-3 activity and typical ladder pattern of internucleosomal fragmentation on gel electrophoresis (characteristic of apoptosis) on injecting 800 μg/0.1 mL MTX into the vitreous cavity. 7…”

Electrophysiological Monitoring of Focal and Entire Retinal Function during Treatment with Intravitreal Methotrexate for Intraocular Lymphoma

“…Repeated injections are considered feasible without retinotoxicity [ 10 ], and OCT studies reveal structural recovery after treatment with ivMTX [ 11 ]. However, an experimental study in rabbits analyzed retinal function by ERG after ivMTX, showing significant reduction of the amplitude of a- and b-waves [ 6 ]. These results suggest that there are possible subclinical complications of ivMTX which can only be assessed by ERG.…”

“…A previous report demonstrated the efficiency of intravitreal injections of methotrexate (ivMTX) in treating IOL [ 5 ]. An experimental study in rabbits revealed the retinal cytotoxicity of ivMTX [ 6 ]. However, few reports have evaluated changes in retinal function after ivMTX administration in humans [ 3 ].…”

Intravitreal Methotrexate

“…They showed that high dose intravitreal MTX results in significant ultrastructural changes in the rabbit retina in varying severities. In another study, Aly and Ebrahim [16] assessed the effect of MTX toxicity on electroretinogram (ERG) and retinal caspase-3 activity which has an executive role in apoptosis of pigment epithelial cell, outer nuclear layer cell, and ganglion cells [17] after injection of a single dose of 800 µg MTX. They showed that intravitreal injection of MTX leads to a significant reduction in a-and b-waves with an increase in caspase-3 activity.…”