Determination of the retinal toxicity of intravitreal colistin in rabbit eyes

Abstract

Purpose

To determine the possible adverse effects and safe dose range of intravitreal colistin, an antibiotic, after its intravitreal application.

Methods

Twenty eyes of 20 adult male and female New Zealand white rabbits were selected. Various concentrations of colistin were prepared. In each rabbit, 0.1 mL of colistin solution or saline solution was injected intravitreally into the right eye. Electroretinographic recordings were taken before and 2 weeks after injection. Histopathological examination was made using a light microscope following enucleation and fixation procedures. In histopathologic cross-sections, the differences between drug-injected eyes and control eyes were evaluated.

Results

Electroretinographic examination showed a decrease of 30% as a significant value in the a and b wave amplitudes of the rabbits that injected 400 µg/0.1 ml and higher concentrations. Histological examination revealed histiocytic infiltration, histiocytic vacuoles, inflammation, and retinal degeneration in rabbit eyes given 400 µg/0.1 ml, 800 µg/0.1 ml, and 1.6 mg/0.1 ml concentrations of colistin.

Conclusion

Based on our findings, the safe concentration of colistin is 0.2 mg/0.1 ml. Administration of 0.4 mg/0.1 ml was associated with cataract development, electrophysiological depression, and pathological changes in retinal layers.

Keywords:

• Colistin
• intravitreal injection
• retinal toxicity
• electroretinography
• endophthalmitis

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Correction

Disclosure statement

The authors report no conflict of interest.

Correction Statement

This article was originally published with errors, which have now been corrected in the online version. Please see Correction (http://dx.doi.org/10.1080/15569527.2022.2113957)