Purchase this article with an account.
H. Tsuruga, H. Murata, M. Aihara, M. Araie; Retinotopy in the Optic Nerve Using CFP-Expressing Transgenic Mouse. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5828.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate topographic localization of the axons in the mouse optic nerve corresponding to the each retinal quadrant.
B6.Cg-TgN(Thy1-CFP)23Jrs mice expressing cyan fluorescent protein (CFP) in RGCs were used. One or three areas of retinal quadrants (superior, inferior, temporal, nasal) of right eyes were destroyed by laser photocoagulation in the mice. After a survival period over 2weeks, the mice were deeply anesthetized with a xylazine/ketamin mixture and transcardially perfused with 4% paraformaldehyde. The eyes with optic nerve and the brains were then enucleated. Frozen cross-sections of optic nerve with 10µm thickness were excised from 0 to 3000µm area from the optic nerve head, and stained with GFAP and DAPI. Fluorescent images of CFP (axon), GFAP (astrocyte), and DAPI (nucleus) were obtained using a fluorescence microscope with appropriate filters.
The degeneration patterns of the axons were easily identified by the expression of CFP indicating retinotopy in the optic nerve. The axons of each retinal quadrant were clustered and orderly changed their position through the optic disc and the anterior portion (0-1000µm) of the optic nerve. At 1000µm, 4 clusters of axons in each retinal quadrant queued up in order of inferior, temporal, superior, nasal and inferior quadrant clusters from the lateral side of the optic nerve. Interestingly, the inferior quadrant axons located at the ventral side at the optic nerve head were divided into two clusters and occupied the lateral and medial sides of the optic nerve at posterior optic nerve. Then, the axons of every retinal quadrant were diffusely distributed at 3000µm from the optic disc and remained ubiquitously dispersed through the optic chiasm and into the optic tract.
We could easily identified topographic localization of the axons corresponding areas of the retinal quadrants in optic pathway using transgenic mice which express CFP in RGCs. Retinal axons were located regularly within 1000um from optic disc, but lost their retinotopic order at the posterior in optic nerve. This study will be useful for investigating retinotopy or optic nerve degeneration in mouse ocular models.
This PDF is available to Subscribers Only