Inducing Local Demyelination in the Optic Nerve Using Lysolecithin

Begin with an anesthetized rat and make an incision above the eye orbit.

Dissect the subcutaneous tissue to access the orbital cavity, which contains the optic nerve.

Under a microscope, dissect the conjunctiva, followed by the underlying connective tissue.

Then, retract the surrounding muscles and the gland. Cut the protective layers to expose the optic nerve.

The optic nerve consists of lipid-rich myelinated nerve fibers that transmit electrical signals.

Next, take a pre-assembled glass micropipette filled with lysolecithin, a lipid-disrupting agent, and a dye for visual tracking.

Insert the micropipette into the exposed optic nerve and inject the lysolecithin.

Suture the skin incision and apply antibiotic ointment to prevent infection, then allow the rat to recover.

In the optic nerve, injected lysolecithin disrupts the integrity of the myelin sheath surrounding the nerve fibers.

This results in localized demyelination, reducing signal transmission through the optic nerve.

Prepare the animal for surgery as previously described, and make a 1 to 1.5-centimeter skin incision above the orbit of either eye. With fine iris scissors, open the subcutaneous tissue and access the orbital cavity. Then, under a stereoscope, open the conjunctiva and anterior Tenon's capsule.

Next, retract the extraocular muscles and intraorbital lacrimal glands to expose about 3 millimeters of the optic nerve. Around the optic nerve, use an ophthalmic blade to open the dura and arachnoid mater layers longitudinally, then insert a glass micropipette attached to a Hamilton syringe into the nerve 2 millimeters posterior to the globe.

Over 30 seconds, inject a bolus of lysolecithin with dye. To complete the procedure, suture the skin incision, apply antibiotic ointment to prevent infection, move the animal to a warming pad, and monitor it until it recovers.