Retinal atrophy induced by intravitreous colchicine

Area of Science:

• Ophthalmology
• Neuroscience
• Toxicology

Background:

• Colchicine is known to inhibit axoplasmic transport in ganglion cells.
• Previous studies indicated reversible retinal changes in animals with low-dose intravitreal colchicine.

Purpose of the Study:

• To investigate the effects of intravitreal colchicine on monkey retinas.
• To determine the dose-dependent toxicity and morphologic changes induced by colchicine.

Main Methods:

• Ophthalmoscopy, light microscopy, and electron microscopy were used.
• Monkeys received single doses of intravitreal colchicine ranging from 1.0 to 100 micrograms.

Main Results:

• Optic atrophy was observed within 4 weeks after doses of 10 micrograms or more.
• Morphologic changes included neuronal swelling, fibrillogranular material accumulation, organelle displacement, and microtubule loss.
• Plasmalemmal rupture occurred in ganglion cells and photoreceptors at doses as low as 1 microgram, with relative cone cell sparing.

Conclusions:

• Monkey retinas are more sensitive to intravitreal colchicine than those of some lower animals.
• Colchicine induces significant optic nerve and retinal damage, including neuronal cell death and structural alterations.