Performing Injection into Orbital Lobe of Superior Lacrimal Gland: A Technique for Inducing Dry Eye Disease in Rabbit Model

The superior lacrimal gland is located laterally above the eyeball. The upper part of this gland is known as the orbital lobe. This lobe exhibits a tubuloalveolar architecture, containing a tubular end that branches into multiple alveoli-shaped sacs.

These sacs are lined by the serous cells that secrete the lacrimal fluid - an aqueous protective secretion. This fluid reaches the lacrimal ducts and flows over the ocular surface to lubricate it. Reduced secretion of this fluid results in dry eye disease, or DED.

To induce DED, place an anesthetized rabbit in the prone position. Apply medial pressure on the eye globe, causing the orbital lobe of the gland to protrude from the posterior incisure in the eye orbit. Advance forceps from the scalp until the protrusion site. Make a small indentation on the scalp to demarcate the needle insertion area.

Take a syringe assembly containing the Concanavalin A, or Con A solution, and insert it perpendicularly until the skull bone. Reorient the needle to reach the orbital lobe and inject the Con A solution into the orbital lobe.

Con A, an immune system activator, induces lymphocyte infiltration in the lacrimal gland. This phenomenon leads to the disintegration of the extracellular matrix network, distorting the gland's tubuloalveolar architecture. Eventually, these changes block the secretion of the lacrimal fluid, producing DED in the rabbit eye.

Apply medial pressure to the globe to cause the orbital superior lacrimal gland to protrude from the posterior incisure. Using closed curved forceps, indent the area until the bony opening in the skull is felt, and apply further modest pressure with forceps to leave an indentation in the skin to serve as the landmark for the needle placement.

Insert a tuberculin syringe equipped with a 27-gauge needle perpendicular to the skin over the indentation mark about a 1/4 inch into the incision, and redirect the needle posteriorly and externally toward the lateral canthus, aiming for the midpoint between the injection site and the bony orbital rim. Once the hub of the needle is reached, slowly inject 0.2 milliliters of a 1,000 microgram solution of conA.