Abstract
Purpose: :
To determine if elastin is present in the sclera and peripapillary region of the normal mouse eye and if its configuration changes with age or in the glaucomatous mouse.
Methods: :
Ten C57/Bl6 mice at 2 months of age and 10 at 12 months of age, DBA/2J mice at 2 and 14 months of age (10 each) were studied after fixation at 15 mm Hg prior to cryopreservation. Serial cross sections were taken from the optic nerve to the inner retina, including the optic nerve head and stained with the Luna stain or anti-elastin antibodies. The fellow eye of each mouse was fixed and studied for ultrastructure and distribution of elastin.
Results: :
Elastin fibers were identified in the peripapillary sclera, where the fibers were oriented circumferentially into a ring-like structure. The circumferential fiber ring extended up to 100 microns away from the optic nerve head margin. Second, elastin was prominently found in the portion of the sclera adjacent to the choroid but not elsewhere in the sclera. Finally, there is extensive elastin in the dura and conjunctiva. Axial length of DBA/2J mouse eyes was confirmed to increase by 10% in older mice with nerve damage, but their optic nerve head canal was found to be proportionately less enlarged. Qualitative differences between eyes with age and after glaucomatous injury were seen and will be described.
Conclusions: :
This is the first report of elastin in the peripapillary sclera of the mouse, similar in configuration to that seen in human eyes. Coupled with biomechanical inflation studies of mouse eyes that we are performing, these findings will inform modeling and provide explanations of the IOP-induced effects that contribute to glaucoma injury.
Keywords: sclera • extracellular matrix • optic nerve